Ethylene dimethacrylate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well conducted study, carried out by Nippon Bioresearch Inc.Hashima Laboratory (Japan).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Combined Repeated Dose and Reproductive / Developmental Toxicity Screening Test (Precursor Protocol of GL 422)

Deviations:

yes

Remarks:

older version of method that did not contain the functional observational battery

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxyethyl methacrylate

EC Number:

212-782-2

EC Name:

2-hydroxyethyl methacrylate

Cas Number:

868-77-9

Molecular formula:

C6H10O3

IUPAC Name:

2-hydroxyethyl methacrylate

Details on test material:

- Purity: 97.6 %

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan
- Age at study initiation: 10 weeks
- Weight at study initiation: male 341~380 g; the female was 232~256 g.
- Housing: suspended, stainless steel cage; 5/cage until breeding, then divided into separate rearing cages.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 day quarantine; 7 day acclimation

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ~ 24 ℃
- Humidity (%): 40 to 70%
- Photoperiod (hrs dark / hrs light): 12 hour light / 12 hour dark

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: dissolved in water

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: 14 days
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged (how): separate rearing cages

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

Exposure period: Males, 49 days; Females, from 14 days before mating to day 3 of lactation
Premating exposure period (males): 14 days
Premating exposure period (females): 14 days
Duration of test: Male, 50 days; Females, day 4 of lactation

Frequency of treatment:

Once daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (vehicle), 30, 100, 300, 1000 mg/kg/day
Basis:

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

Post-exposure period: Male, 50 days; Females, day 4 of lactation
- Dose selection rationale: based on range-finding
- Rationale for animal assignment (if not random): random

Positive control:

not applicable

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily
- Cage side observations checked : general condition and mortality; estrus and abnormal labor conditions in females

BODY WEIGHT: Yes
- Time schedule for examinations: twice per week in males; before mating, twice a week during the mating period, 0, 7 ,14 and 21 days duirng pregnancy, during the feeding period was measured 0 and 4 days in females

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): one week prior to mating, then twice a week; additionally, in females, days 2,9,16 and 21 of pregnancy, four days over the feeding period.
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: day after treatment
- Anaesthetic used for blood collection: Yes; sodium pentobarbital
- Animals fasted: No data
- How many animals: No data
- Parameters checked in table [No.1] were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day after treatment
- Animals fasted: No data
- How many animals: No data
- Parameters checked in table [No.2] were examined.

URINALYSIS: No

Oestrous cyclicity (parental animals):

Once daily from the dosing start date until successful mating was observed.

Sperm parameters (parental animals):

Parameters examined in P male parental generations:
testis weight, epididymis weight

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; possible cause of death was not determined for pups born or found dead

Postmortem examinations (parental animals):

Terminal kill: Males, day 50; Females, day 4 of lactation

GROSS PATHOLOGY: Yes; Thymus, liver, kidney, testis and epididymis weight in males and ovary in females was measured after removal, adrenal gland, brain, heart and spleen and 10% neutral buffered formalin solution (However, testicular and epididymal fluid Buan) was fixed. Post-mortem examination of feamles who did not give birth to Day 25 of pregnancy. Number of corpora lutea and the number of implantation scars in females.

HISTOPATHOLOGY: Yes; Paraffin-embedded specimens were prepared. Control group and 1000 mg / kg group of heart, liver, spleen, thymus, kidney, testis and epididymis in males ovary in females, adrenal and brain for the Preparation HE staining of tissue was examined histologically. In males, 1000 mg / kg in the kidney was considered to indicate a difference in the number of abnormal animals in the test group compared with the control group; 30, 100 and 300 mg / kg group were similarly examined. In females, 1000 mg / kg differences in the brain was considered to indicate an abnormal number of animals in the test group than the control group and changes in adrenal cases and 30, 100, 300 mg / kg group were similarly examined.

Statistics:

Newborn screening as a unit has an average of one litter.
Weight (the parent animals, babies), food consumption, number of estrus, days mating, pregnancy [Day delivery (feeding 0) - date confirmed mating, the number of implantation scars, the number of birth control mobilize (number of babies stillborn baby + ), the number of newborn, number of children born dead, birth rate [(number of birth control mobilize / number of implantation scars) × 100], rate of production of child [(number of infant feeding 0 days / number of implantation scars) × 100], corpus number, implantation rates [(number of implantation scars / number of corpora lutea) × 100], fertility [(number of infant feeding 0 day / mobilize all of birth control) × 100], feeding baby number four day, feeding 4 day survival rate [(number of infant feeding 4 days / 0 Number of infant feeding day) × 100], unusual occurrence rate [(number of children with abnormal/ number of newborns) × 100], sex ratio (male / female), organ weights ( including the relative weight), results of blood tests, blood biochemistry test results for the mean and standard deviation were calculated for each group.
Significant difference test, Bartlett's test and the homoscedasticity of Law, analysis of variance, Dunnett method. Kruskal-Wallis test.
Copulation rate [(number of established animal mating / number of live animals) × 100], fertility [(number of female fertility / Establishment of animal mating) × 100], the birth rate [(number of female newborns / number of female fertility) × 100] is, χ ^ 2 using the test.
Cochran • Armitage was carried out using a test of dose-response trend test.

Reproductive indices:

Copulation rate [(number of established animal mating / number of live animals) × 100], fertility [(number of female fertility / Establishment of animal mating) × 100], pregnancy [Day delivery (feeding 0) - date confirmed mating, birth rate [(number of birth control mobilize / number of implantation scars) × 100], rate of production of child [(number of infant feeding 0 days / number of implantation scars) × 100], implantation rates [(number of implantation scars / number of corpora lutea) × 100], fertility [(number of infant feeding 0 day / mobilize all of birth control) × 100]

Offspring viability indices:

the birth rate [(number of female newborns / number of female fertility) × 100], unusual occurrence rate [(number of children with abnormal/ number of newborns) × 100], feeding 4 day survival rate [(number of infant feeding 4 days / 0 Number of infant feeding day) × 100]

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

effects observed, treatment-related

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Details on results (P0)

Detail:[Males]
1) General condition: With the survival animals, no death and no moribund  were found for 30, 100 and 300 mg/kg/day groups. At 1000 mg/kg/day, one  death on day 20 of dosing was seen and abnormality wasn't seen except for  salivation until the previous day.  With the dead animals, no abnormality  was found for 30, 100 and 300 mg/kg/day groups.  At 1000 mg/kg/day,  salivation was seen in about 1 to 30-minutes after dosing from day 3. 2) Body weight: No significant difference from control group was seen in  30, 100, and 300 mg/kg/day groups. At 1000 mg/kg/day, the significant low  value was recorded during day 18 to day 25 of dosing andduring day 32 to  day 50 of dosing.
3) Food consumption: At 30 and 300 mg/kg/day, no significant difference  from control was seen. At 100 mg/kg/day, the significant high values were  seen on day 31. but no dose-related changes were obserbed.At 1000  mg/kg/day, the statistically significant low values were recorded on day  13, 31 and during day 38 to day 45. 
4) Hematological examination: No significant difference from control  group was seen for all groups up to 1000 mg/kg/day dose.
5) Blood chemical examination: At 30 and 300 mg/kg/day,the significant  high value in BUN were seen. As the difference was very small, this was  not considered as the adverse effect of HEMA dosing.  At 100 mg/kg/day, a  higher value of BUN but not statistically signifficant difference from  control was recorded. At 1000 mg/kg/day, the significant high values were  recorded in BUN, K, Cl,I-phosphorous and Triglyceride. 
6) Autopsy: No abnormalitywas found for 30 and 100 mg/kg groups. In the  300 mg/kg group, the albedo spot in the kidney of the unilateral in the 1  animal and, the atrophy of the testiculus of the bilaterality and  softening were observed in the 1 animal. In the 1000 mg/kg group, the  dark-red of the thymus gland in the 1 animal and the hypertrophy of the  kidney of bilaterality in the 1 animal were observed. 
7) Weight oforgans: At 30 mg/kg/day, no significant difference from  control group in absolute and relative weight was seen for all organs. At  100 and 300 mg/kg/day, the significant high value was recorded in the  absolute weight of kidneys. At 1000 mg/kg/day, the statistically  significant high values were recorded in the relative weight of liver and  kidneys.
8) Histopathological examination: At 1000 mg/kg/day in the survival  animals, the dilatation of renal tubule in 3 animals in the kidney and  the dilatation of collecting tubules in 2 animals were observed. But, all  these changes were just slight. And the dilatation of renal tubule has a  significant difference but no dose-related changes.  As for the  dilatation of collecting tubules, it has no significant difference but  increase tendency. In the other group, there were hemorrhage of thymus  gland, microgranuloma of the heart, microgranuloma of the liver and  hepatocyte vacuolar degeneration of the centrilobular, renal basophilic  tubules, eosinophilic corpuscle in proximal tubule, cyst, diffusive  mineral deposition and neutrophilic infiltration. But it was judged with  the incidental change, because they were whether it equivalently seems  even in the control group or small number animals. And no abnormality was  observed in spleen, adrenal, testiculus and brain in the control and 1000  mg/kg group. In animal of death of the 1000 mg/kg group, there were  hemorrhage of the thymus gland, edema of the lung, autolysis of adrenal  and lung and thymus gland with the deadanimal of 1000 mg/kg group. As for  those degrees, all were just slight. In the adrenal with the abnormality  in the autopsy, no change which suggested hypertrophy was seen.   
[Females]
1) General condition: With the existence animales, no death and no  moribund were seen for 30, 100 and 300 mg/kg/day groups. At 1000  mg/kg/day, three death on day 6 of dosing, one death on day 12 of dosing  and one death on day 17 of dosing were seen. Salivation, decrease in  locomotor activity, adoption of a prone position, acrimation, soiled fur,  hypothermia, bradypnea were seen at 1000 mg/kg. With the death animals,  no abnormality was found for 30, 100 and300 mg/kg/day groups.  At 1000  mg/kg/day, salivation was seen in about 1 to 30-minutes after dosing from  day 3.
2) Body weight: Before mating period, no significant difference from control  group was seen at 30, 100 and 300 mg/kg/day. At 1000 mg/kg/day, the  significant lower values were recorded on day 4 and 5 of dosing. During  gestation period, no significant difference from control groups was seen  in 30, 300 and 1000 mg/kg/day groups. At 100 mg/kg/day, the significant  high values were recorded on day 21 of gestation,  but no dose-related  changes were observed. During lactation period, no significant difference  from control groups was seen in 300 and 1000 mg/kg/day groups. At 30 and  100 mg/kg/day, the significant high values were recorded on day 4 of  lactation, but no dose-related changes were obserbed.
3) Food consumption:  Before mating period, no significant difference from control group was  seen at 30, 100 and 300 mg/kg/day. At 1000 mg/kg/day, the significant low  value from control group was recorded on day 3, 6 and 13 of dosing. During  gestation period, no significant difference from control groups was seen  in 30 and 300 mg/kg/day groups. At 100 and 1000 mg/kg/day, the  significant high value from control group was recorded on day 16 of  gestation, but no dose-related changes were observed. During lactation  period, no significant difference from control groups was seen.
4) Weight of organs: At 30 mg/kg/day, no significant difference from  control group in absolute and relative weight was seen for all organs. At  100 mg/kg/day,the significant high value was recorded in the absolute  weight of kidneys. At 1000 mg/kg/day, the significant high values were  recorded in the relative and absolute weight of kidneys. 
5) Histopathological examination: Though at 1000 mg/kg/day survival  groups, neutrophilic infiltration (unilateral ) to medulla and papilla  mammae part in the kidney were observed in the 1 animal, the degree was  slight. Though extensive softening of the medulla oblongata in the brain  was observed in the 1 example at 1000 mg/kg group, the degree was slight.   In dead 6 animals of the 1000 mg/kg group, there were the edema in 1  animal in the lung, the atrophy in 1 animal in the thymus gland, the  atrophy in 5 animals and the atrophy of a Malpighian body in 1 animals in  the spleen, the hyperplasia of zona fasciculata in 3 animals and the  autolysis in 1 animal in the the adrenal and the erosion in 1 animal in  the small intestinal mucosa. The degrees of the atrophy in the thymus  gland and the atrophy of a Malpighian body were moderate, but the others  were slight.  All the changes are noted related agonism. No changes which  suggested, though the hypertrophy of the adrenal in 2 animals, dark-red  of the glandular stomach mucosa in 2 animals and dark-red of the  intestinum tenue were observed as abnormal in the autopsy of the 1000  mg/kg group.

There were no effects of the test substance on the estrus frequency, copulation index, number of conceiving days, fertility index, length of gestation, number of corpora lutea or gestation index.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: highest dose tested

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Details on results (F1)

There were no effects of the test substance on the number of live pups born, birth index, number of dead pups, number of pups born, delivery index, live birth index, sex ratio, viability index, external anomalies, body weight or necropsy findings.

Effect levels (F1)

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

>= 1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: highest dose tested

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

An OECD 422 study was conducted with rats by gavage at doses of 0, 30, 100, 300 and 1000 mg/kg. The NOAEL for reproductive/developmental toxicity and is considered to be greater than 1000 mg/kg.

Executive summary:

2-Hydroxyethyl methacrylate was studied for oral toxicity in rats in an OECD combined repeat dose and reproductive/developmental toxicity screening test at doses of 0, 30, 100, 300 and 1000 mg/kg/day.

There were no effects of the test substance on the estrus frequency, copulation index, number of conceiving days, fertility index, length of gestation, number of corpora lutea or gestation index.

There were no effects of the test substance on the number of live pups born, birth index, number of dead pups, number of pups born, delivery index, live birth index, sex ratio, viability index, external anomalies, body weight or necropsy findings.

Therefore, the NOAELs for reproductive/developmental toxicity are considered to be >/=1000 mg/kg/day for reproductin in both males and females and as well as for development of pups.