1,10-decanediyl bismethacrylate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 20 April to 25 June 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Tetramethylene dimethacrylate

EC Number:

218-218-1

EC Name:

Tetramethylene dimethacrylate

Cas Number:

2082-81-7

Molecular formula:

C12H18O4

IUPAC Name:

butane-1,4-diyl bis(2-methylacrylate)

Test material form:

liquid

Details on test material:

Identity : 1,4-Butanediol dimethacrylate
Appearance: : Yellowish clear liquid
Storage conditions : Room temperature, protected from light

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Italy s.r.l., San Pietro al Natisone (UD), Italy. Animals were bred by Harlan Laboratories Netherland - Kreuzelweg 53, 5961 NM Horst
P.O. Box 6174 NL 5960 AD Horst (Netherlands).
- Age at study initiation: 9 to 10 weeks old (day of allocation)
- Weight at study initiation: (P) Males: 279-280g; Females: 214-216g (day of allocation)
- Fasting period before study: no
- Housing: 5 sex/cage
- Diet (e.g. ad libitum): ad libitum except for clinical pathology
- Water (e.g. ad libitum): ad libitum except for clinical pathology
- Acclimation period: circa 3 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C +/- 2°C
- Humidity (%): 55% +/- 15%
- Air changes (per hr): approximately 15 to 20 air changes per hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: from 26 April (day of allocation) to 25 June 2012

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: daily

DIET PREPARATION
- Rate of preparation of diet (frequency):
- Mixing appropriate amounts with (Type of food):
- Storage temperature of food:

VEHICLE
- Justification for use and choice of vehicle (if other than water): solubility of the test item
- Concentration in vehicle: 20, 60 and 200 mg/mL
- Amount of vehicle (if gavage): 10 mg/mL
- Lot/batch no. (if required):
- Purity:
PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency):
- Mixing appropriate amounts with (Type of food):
- Storage temperature of food:

VEHICLE
- Justification for use and choice of vehicle (if other than water): solubility of test item
- Concentration in vehicle: 20, 60 and 200 mg/mL
- Amount of vehicle (if gavage): 5 mL/kg bw
- Lot/batch no. (if required):
- Purity:

Details on mating procedure:

- M/F ratio per cage: one male to one female
- Length of cohabitation: up to 14 days
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged: single
- Any other deviations from standard protocol:no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Prior to commencement of treatment, analysis was performed to confirm that the proposed formulation procedure was acceptable (check of concentration and homogeneity).
The stability was found to be 24 hours at room temperature in the concentration range of 20 to 200 mg/mL.
Samples of the formulations prepared on Weeks 1 and 6 (when all females were present) were also analysed to check the concentration and homogeneity.
The overall results of the analyses were within the limits of acceptance stated in RTC’s SOPs for concentration (90-110%) and homogeneity (CV <10%).
Chemical analysis was carried out by the Analytical Chemistry Department at RTC according to a validated method (RTC Study No. 90770), in the range from 1.0 to 200 mg/mL. The software used for this activity was the Empower® Pro build No. 2154.

Duration of treatment / exposure:

Males
Animals were dosed once a day, 7 days a week, for 2 consecutive weeks prior to pairing and thereafter through the day before necropsy.
Dose volumes were adjusted once per week for each animal according to the last recorded body weight.

Females
Animals were dosed once a day, 7 days a week, for 2 consecutive weeks prior to pairing and thereafter during pairing (up to Day 40 of pairing for female no. 90760079 which did not mate), post coitum (up to Day 26 for non pregnant females) and post partum periods until Day 3 post partum. Dose volumes were adjusted once per week for each animal according to the last recorded body weight.
During the gestation period, dose volumes were calculated according to individual body weight on Days 0, 7, 14 and 20 post coitum and on Day 1 post partum. Thereafter individual dose volumes remained constant.

Frequency of treatment:

Once a day

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

300 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day

No. of animals per sex per dose:

3 groups of 10 males and 10 females each. A similar constituted control group (Group 1) received the vehicle alone.

Control animals:

yes

Details on study design:

The test item was administered orally by gavage to parental animals at 5 mL/kg body weight.
The dosages, selected in consultation with the Sponsor, were 100, 300 and 1000 mg/kg/day.

Examinations

Parental animals: Observations and examinations:

Mortality

Throughout the study, all animals were checked early in each working day and again in the afternoon. At weekends and Public Holidays a similar procedure was followed except that the final check was carried out at approximately mid-day.

Clinical signs

All clinical signs were recorded for individual animals.
Once before commencement of treatment and at least once daily during the study, each animal was observed and any clinical signs were record.
Observations were performed at the same time interval each day, the interval was selected taking into consideration the presence of post-dose reactions.

Clinical observations (Functional Observation Battery Tests)

Once before commencement of treatment and at least once a week thereafter, each animal was given a detailed clinical examination. Each animal was removed from the home cage and observed in an open arena. The tests included observation of changes in gait and posture, reactivity to handling, presence of clonic or tonic movements, stereotypies or bizarre behaviour and effects on the autonomic nervous system (e.g. lachrymation, piloerection, pupil size, unusual respiratory pattern).
All observations were recorded for individual animals.

Grip strength and sensory reactivity to stimuli

Once during the study, towards the end of treatment, 5 males and 5 females were randomly selected from each group for evaluation of sensory reactivity to stimuli of different modalities (e.g. auditory, visual and proprioceptive stimuli) and for assessment of grip strength. Measurements were performed using a computer generated random order. For males the tests were performed 4 days before necropsy and for females on Day 3 post partum.

Motor activity assessment (MA)

Once during the study, towards the end of treatment, 5 males and 5 females were randomly selected from each group and the motor activity was measured (for approximately 5 minutes) by an automated activity recording device. For males the tests were performed 4 days before necropsy and for females on Day 3 post partum.

Food consumption

The weight of food consumed by each cage of males and females was recorded weekly during the pre-mating period following allocation. The interval between allocation and treatment initiation was less than a full week. Individual food consumption for the females was measured on Days 7, 1 4 and 20 post coitum starting from Day 0 post coitum and on Day 4 post partum starting from Day 1 post partum.

Body weight

Males were weighed on the day of allocation to treatment groups, on the day of treatment commencement, weekly thereafter and at termination.

Females were weighed on the day of allocation to treatment groups, on the day of treatment commencement, weekly thereafter until pairing and on Days 0, 7, 14 and 20 post coitum. Dams were also weighed on Days 1 and 4 post partum.
Body weight measured weekly during the mating phase is not presented in this report but retained and archived as study raw data.
As a part of the sacrificial procedure, samples of blood were withdrawn under isofluorane anaesthesia from the abdominal vena cava from 5 males and 5 females (all females with viable litters with the exception of one not pregnant female of Group 4) randomly selected from each group, under condition of food deprivation.
The blood samples collected were divided into tubes as follows:

EDTA anticoagulant for haematological investigations
Heparin anticoagulant for biochemical tests
Citrate anticoagulant for coagulation tests


The measurements performed on blood samples are listed below:

Haematology

Haematocrit
Haemoglobin
Red blood cell count
Reticulocyte count
Mean red blood cell volume
Mean corpuscular haemoglobin
Mean corpuscular haemoglobin concentration
White blood cell count
Differential leucocyte count - Neutrophils
- Lymphocytes
- Eosinophils
- Basophils
- Monocytes
- Large unstained cells
Platelets

Coagulation tests

Prothrombin time

Clinical chemistry

Alkaline phosphatase
Alanine aminotransferase
Aspartate aminotransferase
Gamma-glutamyltransferase
Urea
Creatinine
Glucose
Triglycerides
Bile acids
Phosphorus
Total bilirubin
Total cholesterol
Total protein
Albumin
Globulin
A/G Ratio
Sodium
Potassium
Calcium
Chloride

Urinalysis (Only males)

At the same time interval as the clinical pathology investigations, individual overnight urine samples were also collected from the same animals under the same conditions. Before starting urine collection, water bottles were removed from each cage and each animal received approximately 10 mL/kg of drinking water by gavage, in order to obtain urine samples suitable for analysis.

Appearance
Volume
Specific gravity
pH
Protein
Glucose
Ketones
Bilirubin
Urobilinogen
Blood

The sediment, obtained from centrifugation at approximately 3000 rpm for 10 minutes, was examined microscopically for:

Epithelial cells
Leucocytes
Erythrocytes
Crystals
Spermatozoa and precursors
Other abnormal components

Oestrous cyclicity (parental animals):

Vaginal smears were taken daily in the morning starting two weeks before pairing until a positive identification of copulation was made.
The vaginal smear data were examined to determine the following:

a) anomalies of the oestrous cycle;
b) pre-coital interval (i.e., the number of nights paired prior to the detection of mating).

Sperm parameters (parental animals):

Parameters examined in [all/P/F1/F2] male parental generations:
testis weight, epididymis weight, morphological evaluation of the seminiferous epithelium (staging of the spermatogenic cycle)

Litter observations:

As soon as possible, after parturition was considered complete (Day 0 or 1 post partum), all pups (live and dead) were counted, sexed and live pups were identified.
Live pups were individually weighed on Days 1 and 4 post partum.
Pups dying during the lactation period were weighed before the despatch to necropsy (these data are not tabulated in this report but archived together with all raw data).
Observation was performed once daily for all litters.

Postmortem examinations (parental animals):

Parental animals were killed by exsanguination under isofluorane anaesthesia.
Pups were euthanised by intraperitoneal injection of Thiopental.

Parental males:
The males were killed after the mating of all females (after 33 days of treatment).

Parental females:
The females with live pups were killed on Day 4 post partum.
One Group 4 female (animal no. 90760079) showing no evidence of copulation was killed after 26 days post coitum from the last day of the mating session.
The females which did not give birth 25 days after positive identification of mating were killed shortly after.

The clinical history of the males and females of the parental generation was studied and a detailed post mortem examination was conducted (including examination of the external surface and orifices).
Changes were noted, the requisite organs weighed and the required tissue samples preserved in fixative and processed for histopathological examination.

Females:
All females were examined also for the following:

a) external and internal abnormalities;
b) number of visible implantation sites (pregnant animals);
c) number of corpora lutea (pregnant animals).

Uteri of females with no visible implantations were immersed in a 20% solution of ammonium sulphide to reveal evidence of implantation.
Organ weights

From all animals completing the scheduled test period, the organs were dissected free of fat and weighed.
The ratios of organ weight to body weight were calculated for each animal.

Tissues fixed and preserved

Samples of all the tissues listed in section 4.5.6 were fixed and preserved in 10% neutral buffered formalin (except testes and epididymides which were fixed in modified Davidson's fluid and preserved in 70% ethyl alcohol).

Histopathological examination

The tissues required for histopathological examination are listed in section 4.5.6. After dehydration and embedding in paraffin wax, sections of the tissues were cut at 5 micrometer thickness and stained with haematoxylin and eosin.
In addition, the testes and epididymides were cut at 2-3 micrometer thickness and stained with Periodic Acid Schiff (PAS). The morphological evaluation of the seminiferous epithelium (staging of spermatogenic cycle) was performed.

In the first instance the examination was restricted as detailed below:

a) Tissues from 5 males and 5 females randomly selected (animals evaluated for clinical pathology) in the control and high dose group.
b) All abnormalities in all groups.

The examination of stomach (both sexes) and liver (only females) was extended to include the remaining 5 males and 5 females (animals not
evaluated for clinical pathology) of the control and high dose group.
In addition, the examination of stomach (both sexes) and liver (only females) was extended to animals of the other dose groups since possible
treatment-related changes were observed in the high dose group.

Postmortem examinations (offspring):

All pups found dead in the cage were examined for external and internal abnormalities. Sex confirmation by gonadal inspection was also performed.
All live pups sacrificed at termination were examined for external abnormalities and sex confirmation by gonadal inspection.

Statistics:

Standard deviations were calculated as appropriate. For continuous variables the significance of the differences amongst group means was assessed by Dunnett’s test or a modified t test, depending on the homogeneity of data.
Statistical analysis of histopathological findings was carried out by means of the non-parametric Kolmogorov-Smirnov test (for stomach and liver).
The non-parametric Kruskal-Wallis analysis of variance was used for the other parameters. Intergroup differences between the control and treated groups were assessed by the non-parametric version of the Williams test.
The criterion for statistical significance was p<0.05 or p<0.01.

Reproductive indices:

Males
Copulatory Index (%)=no. of animals mated/no. of animals paired x 100
Fertility Index (%)=no. of males which induced pregnancy/no. of males paired x 100

Females
Copulatory Index (%)=no. of animals mated/no. of animals paired x 100
Fertility Index (%)=no. of pregnant females/no. of females paired x 100

Males and females
Pre-coital Interval=Mean number of days between pairing and mating

Offspring viability indices:

Pre-implantation loss was calculated as a percentage from the formula:

(No. of corpora lutea - no. of implantations)/No. of corpora lutea x 100

Pre-birth loss was calculated as a percentage from the formula:

(No. of visible implantations - total litter size at birth)/No. of visible implantations x 100

Pup loss at birth was calculated as a percentage from the formula:

(Total litter size - live litter size)/Total litter size x 100

Cumulative pup loss on Day 4 post partum was calculated as a percentage from the formula:

(Total litter size at birth - live litter size at Day 4)/Total litter size at birth x 100

Sex ratios were calculated at birth and on Day 4 post partum and were presented as the percentage of males per litter.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not specified

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight and body weight gain were lower in the high dose group compared to controls throughout the study.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Body weight and body weight gain were lower in the high dose group compared to controls throughout the study.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

The main relevant change was an increased value of bile acids in treated groups compared to controls with clear dose-relation in males.

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Stomach (non-glandular)
The treatment-related change seen in the high dosed animals (1/10 and 5/10, respectively in males and females), consisted of mild diffused hyperplasia of the squamous epithelium in the non-glandural stomach, which was associated with mild thickening (i.e., hyperkerathosis) of the keratin layer. This change was not associated with any indication of inflammation and/or ulceration.

Liver
In 3/10 high dose animals (females), minimal degree of multifocal perilobular hepatocytic vacuolaiton, which is suggested to be consistent with fatty change, was noted. The vacuoles were of mixed type (i.e., micro- and macrovesicular) and no presence of inflammation and/or necrosis was noted.

Histopathological findings: neoplastic:

not examined

Other effects:

not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

effects observed, treatment-related

Description (incidence and severity):

Pre-coital intervals and copulatory index did not show differences between treated and control groups. On the contrary, fertility index was markedly reduced in the high dose group (40% compared to 90% of the control group).

No significant differences were observed in the number of implantation, corpora lutea, total litter size, pre-implantation loss, pre-birth loss and gestation length between control and treated groups.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

Target system / organ toxicity (P0)

Critical effects observed:

no

Results: F1 generation

General toxicity (F1)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Cold to touch and apparently no food intake were the signs noted in pups of the treated groups only.

Dermal irritation (if dermal study):

not specified

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Reduced litter and mean pup weights were found in the high dose group compared to controls.

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

effects observed, treatment-related

Description (incidence and severity):

The percentage of cumulative pup loss on Day 4 post partum starting from the total litter size at birth, was increased in the high dose group. No differences were found in sex ratio between the groups.

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Histopathological findings:

not specified

Other effects:

no effects observed

Description (incidence and severity):

No significant differences were observed in the number of implantation, corpora lutea, total litter size, pre-implantation loss, pre-birth loss and gestation length between control and treated groups.

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

300 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

other: Reduced litter and mean pup weights in high dose group. Percentage of cumulative pup loss on Day 4 post partum starting from the total litter size at birth, increased in high dose group.

Target system / organ toxicity (F1)

Critical effects observed:

no

Overall reproductive toxicity

Reproductive effects observed:

yes

Lowest effective dose / conc.:

1 000 mg/kg bw/day

Treatment related:

yes

Relation to other toxic effects:

reproductive effects as a secondary non-specific consequence of other toxic effects

Dose response relationship:

yes

Relevant for humans:

yes

Any other information on results incl. tables

 Oestrus cycle – Pre-pairing period - Group summary data

 

 STUDY NO.: 90760

 -----------------------------------------------------------------------------------------------------------------------------------

           Group 1              Group 2             Group 3             Group 4

 Animal   Oestrus    Animal   Oestrus   Animal   Oestrus   Animal   Oestrus

 Number   Cycles     Number   Cycles    Number   Cycles    Number   Cycles

 -----------------------------------------------------------------------------------------------------------------------------------

 90760001    2      90760021     3      90760041    3      90760061    2

 90760003    3      90760023     3      90760043    3      90760063    1

 90760005    4      90760025     3      90760045    4      90760065    3

 90760007    2      90760027     2      90760047    3      90760067    2

 90760009    3      90760029     4      90760049    2      90760069    3

 90760011    2      90760031     2      90760051    1      90760071    3

 90760013    2      90760033     1      90760053    1      90760073    1

 90760015    0      90760035     2      90760055    2      90760075    4

 90760017    4      90760037     2      90760057    3      90760077    2

 90760019    2      90760039     3      90760059    3      90760079    3

 

  Mean     2.4                  2.5                 2.5                 2.4

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 Note: The number of oestrus cycles is based on the number of non sequential days the dams were in oestrus.

Reproductive performance

Reproductive parameters of males - Summary

 

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                              Group              1          2         3          4

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   Copulatory Index%                    100.0     100.0      100.0      90.0

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   Fertility Index%                       90.0      90.0      100.0      40.0

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Reproductive parameters of females - Summary

-----------------------------------------------------------------------------------------------------------------------------------

                              Group              1          2         3          4

-----------------------------------------------------------------------------------------------------------------------------------

 

   Copulatory Index%                    100.0     100.0      100.0      90.0

-----------------------------------------------------------------------------------------------------------------------------------

 

   Fertility Index%                           90.0      90.0      100.0      40.0

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Applicant's summary and conclusion

Conclusions:

On the basis of the results obtained in the study, the NOAEL (No Observed Adverse Effect Level) for reproduction/developmental toxicity could be considered 300 mg/kg/day.
The pronounced reduction of body weight gain of the premating animals indicates that the reduced reproduction success is likely a secondary effect of general systemic toxicity resulting in a poor condition of the parent females.

Executive summary:

In a Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test according to OECD Guideline 422 (22 March 1996) 1,4-Butanediol dimethacrylate was administered to 10 Hsd: Sprague Dawley SD rats/sex/dose orally by gavage at dose levels of 0 (control), 100, 300 and 1000 mg/kg bw/d. The treatment schedule included 2 weeks before pairing, during pairing, post coitum and post partum periods up to day 3 post partum. Animals were administered for approximately 5 and 8 weeks for males and females, respectively.

 

No mortality occurred in the study. A total of 8 females were found not pregnant at necropsy: one each in the control and low dose groups and 6 in the high dose group.
The number of females with live pups on Day 4 post-partum were: 9 in the control group, 9 in the low dose group, 10 in the mid-dose group and 4 in the high dose group.
No clinical signs of toxicological significance were reported.

Body weight and body weight gain were lower in the high dose group compared to controls throughout the study.
Food consumption was reduced in the high dose group compared to controls.No relevant differences were noted in all parameters investigated between control and treated groups.
No changes of toxicological significance were found.
The main relevant change was an increased value of bile acids in treated groups compared tocontrols with a clear dose-relation in males.
No changes were recorded in urinalysis.
Measurements of oestrus cycle, pre-coital intervals and copulatory index did not show differences between treated and control groups. On the contrary, fertility index was markedly reduced in the high dose group (40% compared to 90% of the control group).
No significant differences were observed in the number of implantation, corpora lutea, total litter size, pre-implantation loss, pre-birth loss and gestation length between control and treated groups.
Reduced litter and mean pup weights were found in the high dose group compared to controls. The percentage of cumulative pup loss on Day 4 post partum starting from the total litter size at birth, was increased in the high dose group.
No differences were found in sex ratio between the groups.
Small pups were generally observed in all groups including the control group. Cold to touch and apparently no food intake were the signs noted in pups of the treated groups only.
No relevant differences were recorded in decedent pups between the groups.
No abnormalities were observed in pups sacrificed at term.
Terminal body weight was lower in the high dose group compared to controls and this difference was statistically significant in females.
Statistically significant higher kidneys weight was observed in high dose males and females
compared to controls. In addition, thymus weight was significantly decreased in high dose males.
No treatment-related changes were noted at macroscopic examination.
Treatment-related findings at microscpopic observations were limited to the high dosed animals and were seen in the stomach of both sexes and in the liver of the females only.Stomach (non-glandular)
The treatment-related change seen in the high dosed animals (1/10 and 5/10, respectively in males and females), consisted of mild diffused hyperplasia of the squamous epithelium in the non-glandural stomach, which was associated with mild thickening (i.e., hyperkerathosis) of the keratin layer. This change was not associated with any indication of inflammation and/orulceration.
In 3/10 high dose animals (females), minimal degree of multifocal perilobular hepatocytic vacuolaiton, which is suggested to be consistent with fatty change, was noted. The vacuoles were of mixed type (i.e., micro- and macrovesicular) and no presence of inflammation and/ornecrosis was noted.
Evaluation of the spermatogenic cycle did not show differences between the groups. Regular layering in the germinal epithelium was noted.

 

Conclusions

On the basis of the results obtained in the study, the NOAEL (No Observed Adverse Effect Level) for both general toxicity and reproduction/developmental toxicity could be considered 300 mg/kg/day for males and females. The pronounced reduction of body weight gain of the premating animals indicates that the reduced reproduction success is likely a secondary effect of general systemic toxicity resulting in a poor condition of the parent females.