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Description of key information

A two-year feeding study was conducted in rats with MON 13900 in rats. The NOEL was 5 ppm (0.26 mg/kg bw/day) for males and 100 ppm (6.03 mg/kg bw/day) for females.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records
Reference
Endpoint:
repeated dose toxicity: oral
Remarks:
combined repeated dose and carcinogenicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From Aug 1, 1991 to Aug 10, 1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the EPA OPP 83-5 Guideline in compliance with GLP.
Qualifier:
according to
Guideline:
other: EPA OPP 83-5 (Combined Chronic Toxicity / Carcinogenicity)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
no
Species:
rat
Strain:
other: Sprague Dawley (CD)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles fiver Laboratory, Portage, MI
- Age at study initiation: Approx 7 week
- Weight at study initiation: 194 g (males), 183 g (females)
- Housing: Individual stainless steel cages with wire mesh bottoms suspended over paper bedding
- Diet (e.g. ad libitum): PMI Feeds, Inc., Certified rodent Diet #5002,ad libitum
- Water: Ad libitum
Route of administration:
oral: feed
Vehicle:
other: Dietary admixture
Details on oral exposure:
Method of Mixing: The neat test substance was mixed thoroughly with the basal diet using high speed mixers to make a premix from which all dietary levels were made by mixing with appropriate amounts of basal diet.
Diet Storage: After preparation, diets were stored refrigerated and/or kept in the animal room until the time of feeding.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Methods: The neat test substance was analyzed by gas chromatography using a nitrogen phosphorous detector or flame ionization. Dietary mixtures of the test material were analyzed by gas chromatography using an electron capture detector.
Stability of neat test substance: The neat test substances was analyzed near the beginning of the study, at Months 6, 12, 18 and after the last diets for the study were prepared.
Diet mixture stability: At the beginning of the study, samples from the 5, 2000 and 2500 ppm dietary levels were kept at room temperature (open container, 6 or 7 d and 14 d) or frozen (closed container, 35 d) and analyzed. Dietary stability analyses were repeated after the end of the study.
Homogeneity of diet: Duplicate samples from the top, middle and bottom of the mixer of the 5, 2000 and 2500 ppm diets were analyzed at the start of the study and repeated in the second year of the study
Dietary level verification: All diets from the first and third weeks of the study were analyzed, and at least one level per week was analyzed thereafter.
Duration of treatment / exposure:
24 months
Frequency of treatment:
Ad libitum

Remarks:
Doses / Concentrations:
0, 5, 100, 1000, and 2000 (females)/2500 (males) ppm
Basis:
nominal in diet
Remarks:
Doses / Concentrations:
0.26, 5.05, 51.75, and 128.90 mg/kg bw/day for males and 0.29, 6.03, 61.04, and 125.04 mg/kg bw/day for females
Basis:
actual ingested
No. of animals per sex per dose:
72/sex/dose

Control animals:
yes, plain diet
Details on study design:
Animals were observed twice a day for mortality, moribundity and noteworthy signs of toxicity. Body weights and food consumption were determined weekly for the first 13 weeks and at least every four weeks thereafter. Samples were collected at Months 3, 6, 12, 18 and 24 (termination) for hematology, serum chemistry and urine analyses. Ten animals/sex level were sacrificed by design at Month 12. After 24 months all survivors were euthanized, and gross necropsies were performed. Selected tissues were weighed at the scheduled sacrifices. Approx 40 tissues were retained and examined microscopically from all animals at the control and three highest dietary levels. Liver, testes, seminal vesicles and thymus from males and liver from females were examined at the lowest level.
Observations and examinations performed and frequency:
Mortality, Moribundity: Twice daily (AM and PM)
Detailed clinical signs: Once weekly
Body-weight: Prior to randomization, once weekly for the first 13 weeks; at least every 4 weeks thereafter
Food consumption: Weekly for the first 13 weeks; at least every 4 weeks thereafter
Ophthalmic examinations: Prior to study start, all animals prior at 12 and 24 months (control and high dose only)
Sacrifice and pathology:
Clinical pathology:
-Frequency: 3, 6, 12, 18 and 24 months (termination)
-Number of animals: 10/sex/level
-Blood collection method: Orbital sinus, 3, 6 and 18 months from halothane-anesthetized rats. Posterior vena cava of CO2-anesthetized rats, 12 and 24 months. Fasted rats
-Hematology: Hematocrit, hemoglobin, red blood cell count, total and differential white blood cell count, red cell ratios (MCV, MCH, MCHC), platelet count, reticulocyte count. Activated partial thromboplastin time (ATPPT) at 12 and 24 months only.
-Blood chemistry: Alanine aminotransferase, aspartate aminotransferase, albumin, alkaline phosphatase, blood urea nitrogen, calcium, chloride, cholesterol, creatine phosphokinase, creatinine, direct bilirubin, gamma glutamyl transferase, glucose, globulin, potassium, phosphorus, sodium, total bilirubin, total protein.
Urine collection method: Urine collection trays for approx 18 h semiquantitative analyses of most parameters.
-Urinalysis: Bilirubin, pH, specific gravity, blood, appearance, glucose, ketones, protein, urobilinogen, volume, microscopic sediment
-Gross pathology: Sacrificed by CO2 anesthesia and exsanguination
-Interim sacrifice: 12 months: 10/sex/group
-Terminal sacrifice: 24 months: all survivors
-Animal examined: All
-Organ weighted: Adrenals, brain, kidneys, liver, thyroids and testes at schedule sacrifices
-Tissue retained: Adrenals, aorta, brain, caecum, colon, duodenum, epididymides, esophagus, eyes, femur with tibio-femoral joint, gross lesions (with possible histopathology correlates), heart, ileum, jejunum, kidneys, liver, lung (with mainstem bronchi), lymph nodes (mesenteric and submaxillary),
masses, muscle (quadriceps femoris), nerve (sciatic), ovaries, pancreas, parathyroids, pituitary, prostate, rectum, salivary gland (submaxillary), seminal vesicles, skin (with mammary tissue), spinal cord (cervical, thorax, lumbar), spleen, sternum (with marrow), stomach, testes, thymus, thyroids, trachea, urinary bladder and uterus (corpus and cervix)
-Fixatives: Eyes-5% neutral buffered formalin/0.5% glutaraldehyde; Remaining tissues-10% neutral buffered formalin
Histopathogy: All retained tissues from all males and females at the control and three highest dietary levels. Livers from all rats. Seminal vesicles, testes and thymus from all males.
Statistics:
-Dunnett’s multiple comparison test (two-tailed): In life body weights, cumulative body weight changes and food consumption data, and urinalysis (specific gravity, pH and volume) data
-EHL decision-tree analysis (two-tailed) tests for normality and homogeneity of variances [Bartiett’s Test], utilizing either parametric [Dunnett’s Test and Linear digression] or nonparametric [Kruskal-Wallis, Jonckheere’s and/or Mann-Whitney Tests] routines to detect differences and analyze for trend. EHL decision-tree analysis (two-tailed): Hematology and blood chemistry data, terminal body weights, absolute organ weights, and organ/body weight and organ/brain weight ratios.
- Fisher’s exact test (one-tailed) with Bonferroni inequality procedure: Incidence of microscopic lesions.
-Grubbs’ test was used to detect outliers in the organ weight data.
- Mortality data (two-tailed): Analyzed by SAS (Statistical Analysis System, statistical analysis, Cary, North Carolina)
- Peto analysis: select histopathologic lesions
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
effects observed, treatment-related
Ophthalmological findings:
no effects observed
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
no effects observed
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
effects observed, treatment-related
Details on results:
Clinical signs and mortality: There were no treatment related effects observed on mortality or clinical signs. Survival at study termination was 48, 39, 51, 41 and 38% in males and 29, 24, 34, 30 and 38% in females from the 0, 5, 100, 1000 and 2000/2500 ppm dietary levels, respectively.

Body weight: Effects on body weight were limited to both sexes from the 1000 and 2000/2500 ppm dietary levels. Mean body weight gain (Day 0-727) was reduced in both sexes from these dietary levels (76% and 71% of control mean values for males and females, respectively, from the 2000/2500 ppm groups; 80% and 88% of control mean values for males and females, respectively, from the 1000 ppm group).

Food consumption: Consistent treatment related effects on food consumption were observed in males only from the 2500 ppm dietary level; reductions in food consumption (85% of the control mean value) were observed for this sex throughout the study. Transient reductions (86% of control mean values) in food consumption were observed for females, and both sexes from the 2000 and 1000 ppm dietary levels, respectively, during the first 3 months of the study.

Ophthalmological examination: No treatment-related effects observed.

Haematology, clinical chemistry and urinalysis: Treatment related effects on haematology parameters were limited to both sexes from the 2000/2500 ppm dietary level. Slight statistically significant reductions in RBC counts, haemaglobin and hematocrit (≥82% of control mean values) were observed for males and females during the last 6 months and, during the first year of the study, respectively. A slight decrease (≥94% of the control mean value) in MCV and/or, increase in MCHC and PLT counts (≤114% and ≤141% of control mean values, respectively) was observed in females after 3 months of administration. Treatment-related effects on clinical chemistry parameters were limited to both sexes from the 1000 and 2000/2500 ppm dietary levels. Gamma-GT, direct and total bilirubin, and cholesterol were increased and, ALT/SGPT was decreased in both sexes from the 2000/2500 ppm dietary level after 6 months of administration. BUN was increased in females from the 2000 ppm dietary level at study termination. With the exception of total bilirubin and cholesterol (males) and, direct bilirubin (females) similar effects were observed on these parameters in both sexes from the 1000 ppm dietary level. No treatment related effects were observed on urinalysis parameters.

Gross pathology: Treatment-related increases in mean absolute ant/or relative (to body or brain) weights generally occurred at the two highest levels in both males and females. Increased relative brain weights at termination in the two highest level groups of males and/or females resulted from the decreased terminal body weights. Decreases in the absolute adrenal weights and/or adrenal/brain weights in high level males and females were considered treatment related and were generally statistically significant at one or both of the schedule sacrifice intervals. There were notable increases in the absolute and relative liver weights at the two highest levels as well as increased absolute liver weights and liverbody weight ratios in the 100 ppm group males at the terminal sacrifice. Absolute and relative kidney weights of males in the three highest dietary groups were increased. Kidney weights of females in the 2000 ppm group the 1000 ppm group as well as kidney ratios in these groups were also elevated. These effects on kidneys were attributed to treatment. Mean testes body weight ratios in the 2500 and 1000 pm group were increased at one or both sacrifice-intervals. Mean absolute testes weights of males from the two lowest level groups were decreased compared to control. The increases in relative testicular weights at 2500 and 1000 ppm were considered secondary to decreased body weights and not indicative of a toxic effect on the testes. Treatment-related alterations of the liver, kidney and stomach were observed at necropsy. in the liver, there was an increased incidence of red/purple/black foci in the highest level group of males and in the two highest levels of females. There was also a higher incidence of liver masses/noddes at the 2500 ppm level in males and at the 2000 and 1000 ppm level in females and of cysts in the highest level males and females. In the kidneys, gross enlargement was seen at the 2500 ppm level in males and granular/ pitted surfaces observed at the 2000 and 1000 ppm level in females. A slight increase in the incidence of ulcerated foci in the stomach occurred in males in the 2500 and 1000 ppm groups.

Microscopic pathology: Treatment-related effects on the kidney were increases in incidence of brown pigment in the tubular epithelial cells of males in the 2500 and 1000 ppm groups and 2000 ppm group females. Nephropathy was increased in females from the 2000 and 1000 ppm groups. In the liver, increased incidences of hepatocellar carcinoma occurred in females from the 2000 and 1000 ppm groups, and hepatocelldar adenomas and combined adenomas/carcinomas were seen in males from the 2500 ppm group and females born the two highest levels. A bile duct adenoma was observed in one male from each of the 2500 and 1000 ppm groups. Various non-neoplastic lesions including eosinophilic focus, portal inflammation: portal pigment deposition, bile duct hyperplasia/fibrosis, cystic bile ducts, cystic degeneration, telangiectasis, sinus dilatation and oval/stem cell hyerplasia were significantly increased in males and/or females horn the highest level as well as occasionally from the 1000 ppm level. Squamous mucosa hyperplasia and inflammation of the stomach were increased at the two highest levels in males and/or females. There was an increase in the combined incidence of all squamous cell tumors of the (fore) stomach (benign squamous cell papilloma and malignant squamous cell carcinomas) at 2500 ppm in males. One malignant squamous cell carcinoma was also seen in one male at 1000 ppm and one female at 2000 ppm. A benign squamous cell papilloma occurred in one female at 2000 ppm. In the testes, interstitial cell tumors and interstitial cell hyperplasia were increased at the 2500 and 1000 ppm levels. In the lung, there was a non-statistically significant increase in the incidenceof alveolar lining cell hyperplasia in high level males and females and 1000 ppm level females. One occurrence of bronchoalveolar adenoma in each of the highest level male and female groups and one bronchoalveolar carcinomain a 2000 ppm females was observed.
Dose descriptor:
NOEL
Remarks:
(chronic toxicity)
Effect level:
0.26 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: Effects on body weight, and clinical pathology, organ weight and/or gross and microscopic pathology alterations in the liver, stomach and to a lesser extent, kidneys and testes at higher doses
Dose descriptor:
NOEL
Remarks:
(Chronic toxicity)
Effect level:
6.03 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: Effects on body weight, and clinical pathology, organ weight and/or gross and microscopic pathology alterations in the liver, stomach and to a lesser extent, kidneys and testes at higher doses
Dose descriptor:
dose level: (Carcinogenecity)
Effect level:
0.26 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Hyperplastic and/or neoplastic changes were observed in the liver and stomach of male and female rats and in the testes of male rats at the higher doses.
Critical effects observed:
not specified

Discussion:

Chronic Toxicity: The pattern of systemic toxicity observed in this study indicates that the liver, stomach and to a lesser extent kidneys and testis were the primary target organs for chronic toxicity. In the liver, effects on blood chemistry, such as increased gamma-GT, total and/or direct bilirubin and cholesterol were associated with liver pathology. Liver weights were increased in both sexes at the two highest levels and in males at 100 ppm. Discolored liver foci were observed at gross necropsy with increased frequency in females at 2000 and 1000 ppm. In the stomach of male rats, squamous cell inflammation and hyperplasia in the forestomach were increased at 2500 and 1000 ppm, the two highest levels. Squamous cell erosion/ulceration was increased at the highest level, but the increase was not statistically significant. In female rats, only squamous cell hyperplasia was significantly increased at the 2000 ppm level. In the kidneys, increases in kidney weights in males and females at 2500/2000 and 1000 ppm were considered treatment related and were associated with gross and/or microscopic pathology. Brown pigment accumulation was observed in the kidneys of males in the 2500 ppm and 1000 ppm groups and females in the 2000 ppm group. The incidence of nephropathy was increases in females at 2000 and 1000 ppm. Increased BUN levels in females at the two highest levels were considered secondary to the nephropathy. At 100 ppm in males increased organ weights were not associated with gross or microscopic alterations, but were considered a toxic effect. In the testes of male rats, interstitial cell hyperplasia was significantly increased at 2500 ppm and was increased but not statistically significantat 1000 ppm.

Neoplasia: Histopathologic neoplastic lesions which occurred in the liver and testes were considered treatment-related effects at the 1000 ppm levels in males and/or females.

Liver: The historical control incidence for hepatocellular adenomas is 7% (0-18% range) in males rats and 690 (0-23% range) in female rats in this laboratory. For combined adenomas/carcinomas the historical incidence is 9% (range:0-22%) in males and 8% (range:2-25%) in females. Although the changes in the liver were statistically significant compared with concurrent controls in males at the highest level and in females at the two highest dietary levels, the incidence observed in the present study are at, or only barely above the historical control incidence of these lesions, representing only a weak oncogenic effect at best. There was no statistically significant increase in neoplasia (adenomas and carcinomas separately or combined) in livers from rats fed diets at or below the 1000 ppm level in males or at or below the 100 ppm level in females.

Stomach: Squamous cell carcinomas, squamous papillomas adenocarcinomas were observed in males and/or females and pyloric at the highest dietary level (2500 ppm males and 2000 ppm females) with a single squamous cell carcinoma at the 1000 ppm level in male rats. While the incidence of the tumors were very low (maximum of 3 squamous cell carcinomas in high level males) and were not statistically significant (Fisher’s Exact Test), these tumors are generally not seen in control CD rats in this laboratory. Therefore, the tumors are significant. The pyloric adenocarcinoma is not treatment and considered biologically clearly associated with treatment.

Testes: At both the 2500 and 1000 ppm dietary levels, the incidence of benign interstitial cell tumors was not significantly increased when analyzed using the Bonferroni procedure, but the overall incidence did show a significant trend among groups by Peto analysis and the historical control range in this laboratory is 2 to 6%. The changes at the 2500 and 1000 ppm levels were considered to be biological significant.

Conclusions:
Under the test conditions, the NOEL for chronic toxicity was 5 ppm (0.26 mg/kg bw/day) for male rats and 100 ppm (6.03 mg/kg bw/day) for female rats.
Executive summary:

A two-year feeding study was conducted in rats to evaluate the carcinogenic potential of MON 13900 according to the EPA Guideline OPP 83-5 in compliance with GLP.

Five groups of 72 male and 72 female CD rats were administered diets containing test substance at target concentrations of 0, 5, 100, 1,000, and 2,000 (females)/2,500 (males) ppm for up to 24 months. The study averages for consumption of test substance were 0.26, 5.05, 51.75, and 128.90 mg/kg bw/day for males and 0.29, 6.03, 61.04, and 125.04 mg/kg bw/day for females, respectively. Dietary concentrations were confirmed periodically. There were no treatment related effects observed on mortality or clinical signs. Mean bodyweight gain was reduced in both sexes at 1,000 and 2,000/2,500 ppm (76% and 71% of control mean values for males and females, respectively, from the 2000/2500 ppm groups; 80% and 88% of control mean values for males and females, respectively, from the 1000 ppm group). Consistent treatment-related effects on food consumption were observed in males only at 2500 ppm; reductions in food consumption (85% of the control mean value) were observed for this sex throughout the study. Transient reductions (86% of control mean values) in food consumption were observed for females and both sexes from the 2000 and 1000 ppm dietary levels, respectively, during the first 3 months of the study.  Treatment-related effects on haematology parameters were limited to the 2,000/2,500 ppm dietary level. Slight statistically significant reductions in red blood cell counts, haemaglobin and hematocrit (≥ 82% of control mean values) were observed for males and females during the last 6 months and during the first year of the study, respectively. A slight decrease (≥ 94% of the control mean value) in MCV and/or, increase in MCHC and PLT counts (≤ 114% and ≤ 141% of control mean values, respectively) was observed in females after 3 months of administration. Treatment-related effects on clinical chemistry parameters were limited to the 1,000 and 2,000/2,500 ppm dietary levels. Gamma-GT, direct and total bilirubin, and cholesterol were increased and, ALT/SGPT was decreased in both sexes at 2,000/2,500 ppm after 6 months of administration. BUN was increased in females at 2,000 ppm at study termination. With the exception of total bilirubin and cholesterol (males) and direct bilirubin (females), similar effects were observed on these parameters in both sexes from the 1,000 ppm dietary level. No treatment-related effects were observed on urinalysis parameters. Treatment-related increases in mean absolute ant/or relative (to body or brain) weights generally occurred at the two highest levels in both males and females. Increased relative brain weights at termination in the two highest level groups of males and/or females resulted from the decreased terminal body weights. Decreases in the absolute adrenal weights and/or adrenal/brain weights in high level males and females were considered treatment related and were generally statistically significant at one or both of the schedule sacrifice intervals. There were notable increases in the absolute and relative liver weights at the two highest levels as well as increased absolute liver weights and liverbody weight ratios in the 100 ppm group males at the terminal sacrifice. Absolute and relative kidney weights of males in the three highest dietary groups were increased. Kidney weights of females at 2,000 and 1000 ppm as well as kidney ratios in these groups were also elevated. These effects on kidneys were attributed to treatment. Mean testes body weight ratios in the 2,500 and 1,000 pm group were increased at one or both sacrifice intervals. Mean absolute testes weights of males from the two lowest level groups were decreased compared to control. The increases in relative testicular weights at 2,500 and 1,000 ppm were considered secondary to decreased body weights and not indicative of a toxic effect on the testes. Treatment-related alterations of the liver, kidney and stomach were observed at necropsy. In the liver, there was an increased incidence of red/purple/black foci in the highest level group of males and in the two highest levels of females. There was also a higher incidence of liver masses/nodes at 2,500 ppm in males and at 2,000 and 1000 ppm in females and of cysts in the highest level males and females. In the kidneys, gross enlargement was seen at 2,500 ppm in males and granular/ pitted surfaces observed at 2,000 and 1,000 in females. A slight increase in the incidence of ulcerated foci in the stomach occurred in males at 2,500 and 1,000 ppm. Treatment-related effects on the kidney were increases in incidence of brown pigment in the tubular epithelial cells of males at 2,500 and 1,000 ppm and 2,000 ppm females. Nephropathy was increased in females as of 1,000 ppm. In the liver, increased incidences of hepatocellar carcinoma occurred in females as of 1,000 ppm and hepatocelldar adenomas and combined adenomas/carcinomas were seen in males at 2,500 ppm and females at the two highest levels. A bile duct adenoma was observed in one male at 2,500 and 1,000 ppm. Various non-neoplastic lesions including eosinophilic focus, portal inflammation: portal pigment deposition, bile duct hyperplasia/fibrosis, cystic bile ducts, cystic degeneration, telangiectasis, sinus dilatation and oval/stem cell hyperplasia were significantly increased in males and/or females at the highest level as well as occasionally at 1,000 ppm. Squamous mucosa hyperplasia and inflammation of the stomach were increased at the two highest levels in males and/or females. There was an increase in the combined incidence of all squamous cell tumors of the (fore) stomach (benign squamous cell papilloma and malignant squamous cell carcinomas) at 2,500 ppm in males. One malignant squamous cell carcinoma was also seen in one male at 1,000 ppm and one female at 2,000 ppm. A benign squamous cell papilloma occurred in one female at 2,000 ppm. In the testes, interstitial cell tumors and interstitial cell hyperplasia were increased at 2,500 and 1,000 ppm. In the lung, there was a non-statistically significant increase in the incidence of alveolar lining cell hyperplasia in high level males and females and 1,000 ppm level females. One occurrence of bronchoalveolar adenoma in each of the highest level male and female groups and one bronchoalveolar carcinoma in a 2000 ppm females was observed. Overall, the test substance is considered to have demonstrated significant chronic toxicity and oncogenic effects at dietary concentrations of 2,500 (128.90 mg/kg bw/day) in male rats, at 2,000 (125.04 mg/kg bw/day) in female rats and in males and females at 1,000 ppm (51.75 and 61.04 mg/kg bw/day, respectively). Treatment related increases in liver and kidney weights in males (chronic toxicity) were the only effects noted at 100 ppm (5.05 mg/kg bw/day).

In conclusion, the NOEL for chronic toxicity was 5 ppm (0.26 mg/kg bw/day) for male rats and 100 ppm (6.03 mg/kg bw/day) for female rats.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
0.26 mg/kg bw/day
Study duration:
chronic
Species:
rat
Quality of whole database:
Good quality database

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records
Reference
Endpoint:
repeated dose toxicity: inhalation
Data waiving:
other justification
Justification for data waiving:
other:
Critical effects observed:
not specified
Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Link to relevant study records
Reference
Endpoint:
repeated dose toxicity: inhalation
Data waiving:
other justification
Justification for data waiving:
other:
Critical effects observed:
not specified
Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records
Reference
Endpoint:
short-term repeated dose toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the EPA Guideline OPP 82-2 in compliance with GLP.
Qualifier:
according to
Guideline:
EPA OPP 82-2 (Repeated Dose Dermal Toxicity -21/28 Days)
Deviations:
no
GLP compliance:
yes
Limit test:
no
Species:
other: Albino rat
Strain:
other: Sprague-Dawley (CD)
Sex:
male/female
Details on test animals and environmental conditions:
Source: Charles River Breeding Laboratory, Portage, MI
Sex and numbers: Males, 32; females, 32
Age at study start: Approx 8 wk
Weight range at study start: Males-90.3-329.9 g; females-178.9-209.1 g
All rats were housed one per cage. Information on the temperature and humidity of the animal room was not provided. However, the study authors stated that animal housing and husbandry were in accordance with the provisions of the “Guide to the Care and Use of Laboratory Animals.” Animals were identified by an individual eartag and a barcoded cage card. The animal room was supplied daily with 12 h of light. The rats were acclimated to laboratory conditions for approx 27 d prior to dosing. Purina Certified Rodent Chow #5002 and tap water were provided ad libitum throughout the predose and dosing periods. Rats were assigned into groups according to weight via computer-generated randomization.
Type of coverage:
occlusive
Vehicle:
unchanged (no vehicle)
Details on exposure:
Neat test substance was dermally applied under occlusion to a shaved area (approx 25 cm2) on each animal’s back. The shaved area comprised approximately 10% of the total body surface. The shaved area was covered with a gauze patch and occlusive dressing.
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
21 d
Frequency of treatment:
6 h/d, 5 d/wk
Remarks:
Doses / Concentrations:
25, 250, and 1000 mg/kg bw/day
Basis:
nominal per unit area
No. of animals per sex per dose:
8/sex/dose
Control animals:
yes, concurrent no treatment
Details on study design:
- Dose selection rationale: Based on a previous range-finding study; the range-finding study reported no observed effect level (NOELs) of 500 mg/kg bw/day for males and 1000 mg/kg bw/day for females. The low observed effect level (LOEL) for males was 750 mg/kg bw/day based on a dose-related increase in the incidence of liver foci; a LOEL was not established for females. Liver foci were observed during the macroscopic pathology examination.
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily for mortality and moribundity

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Twice daily for clinical signs of toxicity

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: Throughout the study period

BODY WEIGHT AND FOOD CONSUMPTION: Yes
- Time schedule for examinations: Once weekly

HAEMATOLOGY: Yes

CLINICAL CHEMISTRY: Yes

URINALYSIS: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
Clinical signs:
no effects observed
Dermal irritation:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Haematological findings:
no effects observed
Clinical biochemistry findings:
effects observed, treatment-related
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
General observations: No mortalities occurred during the study. There were no treatment-related signs of dermal irritation or clinical indications of systemic toxicity. No effects were observed on body weight or food consumption.

Haematology and clinical chemistry: There were no alterations in haematological parameters that were considered toxicologically significant. Blood urea nitrogen (BUN) was slightly, but significantly increased (128% of control mean value) in females from the 1000 mg/kg/day group.

Gross pathology, organ weights and histopathology: No treatment-related changes in gross pathology, organ weights or histopathology were observed
Dose descriptor:
NOEL
Remarks:
For local effects
Effect level:
> 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Dose descriptor:
NOEL
Remarks:
For systemic effects
Effect level:
250 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Dose descriptor:
NOEL
Remarks:
For systemic effects
Effect level:
> 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Critical effects observed:
not specified
Conclusions:
Under the test conditions, the NOEL of MON 13900 for the local effects was > 1,000 mg/kg bw/day for males and females. The NOEL for systemic toxicity was determined to be 250 mg/kg bw/day for females and > 1,000 mg/kg bw /day for males.



Executive summary:

A study was conducted to evaluate the subchronic toxic effects of MON 13900 when administered by the dermal route in Sprague-Dawley rats. The study was performed according to the EPA Guideline OPP 82-2 in compliance with GLP.

 

The test substance was administered dermally to three groups of rats at dose levels of 25, 250 and 1,000 mg/kg bw/day. No mortalities occurred during the study. There were no treatment-related signs of dermal irritation or clinical indications of systemic toxicity. No effects were observed on body weight or food consumption. There were no alterations in haematological parameters that were considered toxicologically significant. Blood urea nitrogen (BUN) was slightly, but significantly increased (128% of control mean value) in females from the 1,000 mg/kg bw/day group. No treatment-related changes in gross pathology, organ weights or histopathology were observed.

 

Under the test conditions, the NOEL of the test substance for the local effects was > 1,000 mg/kg bw/day for males and females. The NOEL for systemic toxicity was determined to be 250 mg/kg bw/day for females and > 1,000 mg/kg bw /day for males.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEL
250 mg/kg bw/day
Study duration:
subchronic
Species:
rat
Quality of whole database:
Good quality database

Additional information

A two-year feeding study was conducted in rats to evaluate the oral repeated dose toxicity of MON 13900 according to the EPA Guideline OPP 83-5 in compliance with GLP. Five groups of 72 male and 72 female CD rats were administered diets containing test substance at target concentrations of 0, 5, 100, 1,000, and 2,000 (females)/2,500 (males) ppm for up to 24 months. The study averages for consumption of test substance were 0.26, 5.05, 51.75, and 128.90 mg/kg bw/day for males and 0.29, 6.03, 61.04, and 125.04 mg/kg bw/day for females, respectively. Dietary concentrations were confirmed periodically.

There were no treatment related effects observed on mortality or clinical signs. Mean bodyweight gain was reduced in both sexes at 1,000 and 2,000/2,500. Consistent treatment-related effects on food consumption were observed in males only at 2500 ppm; reductions in food consumption were observed for this sex throughout the study. Transient reductions in food consumption were observed for females and both sexes from the 2000 and 1000 ppm dietary levels, respectively, during the first 3 months of the study.  Treatment-related effects on haematology parameters were limited to the 2,000/2,500 ppm dietary level. Slight statistically significant reductions in red blood cell counts, haemaglobin and hematocrit were observed for males and females during the last 6 months and during the first year of the study, respectively. A slight decrease in MCV and/or increase in MCHC and PLT counts was observed in females after 3 months of administration. Treatment-related effects on clinical chemistry parameters were limited to the 1,000 and 2,000/2,500 ppm dietary levels. Gamma-GT, direct and total bilirubin, and cholesterol were increased and, ALT/SGPT was decreased in both sexes at 2,000/2,500 ppm after 6 months of administration. BUN was increased in females at 2,000 ppm at study termination. With the exception of total bilirubin and cholesterol (males) and direct bilirubin (females), similar effects were observed on these parameters in both sexes from the 1,000 ppm dietary level. No treatment-related effects were observed on urinalysis parameters. Treatment-related increases in mean absolute ant/or relative (to body or brain) weights generally occurred at the two highest levels in both males and females. Increased relative brain weights at termination in the two highest level groups of males and/or females resulted from the decreased terminal body weights. Decreases in the absolute adrenal weights and/or adrenal/brain weights in high level males and females were considered treatment related and were generally statistically significant at one or both of the schedule sacrifice intervals. There were notable increases in the absolute and relative liver weights at the two highest levels as well as increased absolute liver weights and liverbody weight ratios in the 100 ppm group males at the terminal sacrifice. Absolute and relative kidney weights of males in the three highest dietary groups were increased. Kidney weights of females at 2,000 and 1000 ppm as well as kidney ratios in these groups were also elevated. These effects on kidneys were attributed to treatment. Mean testes body weight ratios in the 2,500 and 1,000 pm group were increased at one or both sacrifice intervals. Mean absolute testes weights of males from the two lowest level groups were decreased compared to control. The increases in relative testicular weights at 2,500 and 1,000 ppm were considered secondary to decreased body weights and not indicative of a toxic effect on the testes. Treatment-related alterations of the liver, kidney and stomach were observed at necropsy. In the liver, there was an increased incidence of red/purple/black foci in the highest level group of males and in the two highest levels of females. There was also a higher incidence of liver masses/nodes at 2,500 ppm in males and at 2,000 and 1000 ppm in females and of cysts in the highest level males and females. In the kidneys, gross enlargement was seen at 2,500 ppm in males and granular/ pitted surfaces observed at 2,000 and 1,000 in females. A slight increase in the incidence of ulcerated foci in the stomach occurred in males at 2,500 and 1,000 ppm. Treatment-related effects on the kidney were increases in incidence of brown pigment in the tubular epithelial cells of males at 2,500 and 1,000 ppm and 2,000 ppm females. Nephropathy was increased in females as of 1,000 ppm. In the liver, increased incidences of hepatocellar carcinoma occurred in females as of 1,000 ppm and hepatocelldar adenomas and combined adenomas/carcinomas were seen in males at 2,500 ppm and females at the two highest levels. A bile duct adenoma was observed in one male at 2,500 and 1,000 ppm. Various non-neoplastic lesions including eosinophilic focus, portal inflammation: portal pigment deposition, bile duct hyperplasia/fibrosis, cystic bile ducts, cystic degeneration, telangiectasis, sinus dilatation and oval/stem cell hyperplasia were significantly increased in males and/or females at the highest level as well as occasionally at 1,000 ppm. Squamous mucosa hyperplasia and inflammation of the stomach were increased at the two highest levels in males and/or females. There was an increase in the combined incidence of all squamous cell tumors of the (fore) stomach (benign squamous cell papilloma and malignant squamous cell carcinomas) at 2,500 ppm in males. One malignant squamous cell carcinoma was also seen in one male at 1,000 ppm and one female at 2,000 ppm. A benign squamous cell papilloma occurred in one female at 2,000 ppm. In the testes, interstitial cell tumors and interstitial cell hyperplasia were increased at 2,500 and 1,000 ppm. In the lung, there was a non-statistically significant increase in the incidence of alveolar lining cell hyperplasia in high level males and females and 1,000 ppm level females. One occurrence of bronchoalveolar adenoma in each of the highest level male and female groups and one bronchoalveolar carcinoma in a 2000 ppm female was observed.

Overall, the test substance is considered to have demonstrated chronic toxicity and oncogenic effects at dietary concentrations of 2,500 (128.90 mg/kg bw/day) in male rats, at 2,000 (125.04 mg/kg bw/day) in female rats and in males and females at 1,000 ppm (51.75 and 61.04 mg/kg bw/day, respectively). Treatment-related increases in liver and kidney weights in males (chronic toxicity) were the only effects noted at 100 ppm (5.05 mg/kg bw/day). In conclusion, the NOEL for chronic toxicity was 5 ppm (0.26 mg/kg bw/day) for male rats and 100 ppm (6.03 mg/kg bw/day) for female rats.

In accordance with Annex IX Column 2 of REACH, the repeated dose toxicity study by inhalation does not need to be conducted as exposure of humans via inhalation is unlikely. MON 13900 is applied only once per year at low doses in the form of a liquid formulation and application is done by trained professionals using appropriate risk management measures.

A study was conducted to evaluate the subchronic toxic effects of MON 13900 when administered by the dermal route in Sprague-Dawley rats according to the EPA Guideline OPP 82-2 in compliance with GLP. The test substance was administered dermally to three groups of rats at dose levels of 25, 250 and 1,000 mg/kg bw/day for 21 days. No mortalities occurred during the study. There were no treatment-related signs of dermal irritation or clinical indications of systemic toxicity. No effects were observed on body weight or food consumption. There were no alterations in haematological parameters that were considered toxicologically significant. Blood urea nitrogen (BUN) was slightly, but significantly increased in females from the 1,000 mg/kg bw/day group. No treatment-related changes in gross pathology, organ weights or histopathology were observed. Under the test conditions, the NOEL of the test substance for the local effects was > 1,000 mg/kg bw/day for males and females. The NOEL for systemic toxicity was determined to be 250 mg/kg bw/day for females and > 1,000 mg/kg bw /day for males.


Repeated dose toxicity: via oral route - systemic effects (target organ) digestive: liver

Justification for classification or non-classification

Based on the available repeated dose toxicity data, MON 13900 does not qualify for classification according to EC (67/548/EEC) or CLP (EC 1272/2008) criteria.