Allyl methacrylate

Toxicity to reproduction

Administrative data

Endpoint:

two-generation reproductive toxicity

Remarks:

based on test type (migrated information)

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Peer-reviewed publication suitable for assessment; Allyl methacrylate will be hydrolyzed into allyl alcohol and methacrylic acid. Acrolein is a major toxic metabolite of allyl alcohol and therewith of allyl methacrylate

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1992

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Acrylaldehyde

EC Number:

203-453-4

EC Name:

Acrylaldehyde

Cas Number:

107-02-8

Molecular formula:

C3H4O

IUPAC Name:

acrylaldehyde

Test material form:

other: liquid

Details on test material:

Supplier: Baker Performance Chemicals, Houston, Texas.
Purity:> 96 % (stabilized with 0.25 hydroquinone)
Water content approximately 3 %.

Test animals

Species:

rat

Strain:

other: Crl:CD (SD)BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

- Source: Charles River Breeding Labs., Inc.
- Age at study initiation: 58 days
- Weight at study initiation: Males: 278-375 g; Females: 187-251 g
- Housing: 1-2 rats/sex/cage. All adult rats were housed in suspended stainless-steel cages above absorbent paper liners. Cages were changed every other week and cage pan liners were changed three times a week. During the cohabiting period (maximum period of 21 days), male and female rats of the same dosage group were housed together (1:1). No later that day 14 of presumed gestation, female rats were transferred to a nesting box (1 female per nesting box). During the 21-day postpartum period, each dam was housed in a common nesting box. Nesting boxes contained Bed-o'cobs bedding which was changed three times a week.
- Diet (e.g. ad libitum): certified rodent chow 5002 in meal form ad libitum
- Water (e.g. ad libitum): reverse osmosis membrane treated water (with up to 1 ppm chlorine) ad libitum.
- Acclimation period: 2 weeks

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

Solutions of Acrolein were prepared daily with deionized water. These were analyzed prior to dosing using a spectrophotometer and found to be within 1% of the desired concentration. The stability of Acrolein in deionized water at concentrations of 0.2 and 1.2 mg/ml were investigated at 6 hours after preparation. A loss of 7% and 4% for the low-dose and high-dose, respectively, was observed

Details on mating procedure:

Male/Female ratio per cage: 1:1
Duration of cohabitation: 21 days
Proof of mating: vaginal plug or sperm in vaginal smear referred to as day 0 of presumed gestation.
If pairing was not successful after 14 days, replacement of first male by another male with proven fertility from the same dosage group. After successful conception, each pregnant female was individually housed.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical verification of doses was carried with a Cary 118 twin beam spectrophotometer set at 211 nm.

Duration of treatment / exposure:

For F0 females: 96 - 130 daily doses
For F0 males: 93 - 94 daily doses
For F1 females: 104 - 149 daily doses
For F1 males: 106 - 125 daily doses

Frequency of treatment:

daily.

Details on study schedule:

All rats (male and female) were dosed with the test item Acrolein at 0, 1, 3 and 6 mg/kg at a volume of 5 ml/kg for 70 days. After the dosing period, rats within the same dosage group were housed together at a ratio of 1 male rat to 1 female rat for a minimum period of 14 days. Female rats that had not mated within the 14-day period were housed with a different male rat from the same dosage group for an additional 7 days. Copulatory plugs or spermatozoa in vaginal smears are observation was regarded as day 0 of the presumed gestation period. All female rats received their respective daily dose of Acrolein throughout cohabitation, gestation and lactation; this continued for all female rats until either day 25 of presumed gestation (for females who failed to deliver offspring) or day 21 of lactation (for females that successfully delivered offspring). F0 males were given daily doses up until the scheduled termination date.

F1 pups (40/sex from as many litters as possible/group, at least 1M + 1F/litter where possible) were selected for continuation of the study on day 21 of lactation. These pups received doses beginning on day 21 postpartum. F1 Female rats that had not mated within the 14-day period were housed with a different male rat from the same dosage group for an additional 7 days. When copulatory plugs or spermatozoa in vaginal smears are observed, this was regarded as day 0 of the presumed gestation period. All female rats received their respective daily dose of Acrolein throughout cohabitation, gestation and lactation; this continued for all female rats until either day 25 of presumed gestation (for females delivering no offspring) or day 21 of lactation (for females which successfully delivered offspring). F1 males were given daily doses up until the scheduled termination date.

F2 pups were not directly dosed with Acrolein (but may have been indirectly exposed).

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

1 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

3 mg/kg bw/day (actual dose received)

Doses / concentrations 4

Dose / conc.:

6 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

30

Control animals:

yes

Details on study design:

A range-finding study was carried out with 6 groups of 16 rats (8 male, 8 female). All rats were dosed 7 days prior to cohabitation up to day 25 of presumed gestation or day 4 post partum. At the higher doses (10, 15 and 20 mg/kg), widespread mortality were observed. At doses of 5 mg/kg, clinical signs (including excess salivation, reduced motor activity and respiratory difficulty) were observed. No effect on mating or fertility parameters was seen at 2.5 mg/kg/day. Based on the results of the range-finding study, doses of 0, 1, 3, and 6 mg/kg were used in the main study.

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice a day during study period

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Twice a day

BODY WEIGHT: Yes
- Time schedule for examinations: daily during dosage period.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- For males, this was recorded weekly (except during cohabitation - was recorded but not tabulated) For females, food consumption was recorded weekly prior to cohabitation on days 0, 6, 12, 15, 20 and/or 25 of presumed gestation; in addition on days 1, 4, 7, 10, 14, 16, 18 and 21 of lactation.

OTHER:
For all F0 and F1 female rats:
- The nursing behaviour, caring of pups and other dam-pup interactions were observed on a daily basis, any abnormal maternal behaviour was recorded.
- mating performance was assessed daily during the cohabitation period, confirmed by observed delivery of offspring, confirmed mating date or implantation site at necropsy.
- The duration of gestation and pup viability was assessed.
- Those that did not deliver offspring were killed on day 25 of presumed gestation and examined for implantation sites and gross lesions.

Necropsies were conducted on any deceased F0 and F1 rats.

Oestrous cyclicity (parental animals):

The oestrous cycle was assessed during the cohabitation period (maximum: 21 days) up until the presumed begin of gestation.

Litter observations:

STANDARDIZATION OF LITTERS
-Performed on day 4 postpartum: yes
-If yes, maximum of 10 pups/litter (5/sex/litter as nearly as possible); excess pups were removed
PARAMETERS EXAMINED
The following parameters were examined in F1 / F2 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities.

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; cause of death was determined for pups born or found dead.

Postmortem examinations (parental animals):

SACRIFICE
- Maternal animals: All surviving maternal animals on day 21 of lactation (for females that successfully delivered offspring) or day 25 of presumed gestation period (for females without offspring).

GROSS NECROPSY AND HISTOPATHOLOGY
- Gross necropsy and histopathology was performed on the following organs:
testes, seminal vesicles, epididymides, prostate, ovaries uterus, vagina, kidneys, lungs heart, liver, spleen, stomach, thyroid, pituitary glands, adrenal glands, spinal cord and brain.

Postmortem examinations (offspring):

SACRIFICE
The F1 offspring not selected as parental animals and all F2 offspring were sacrificed on day 21 post partum

GROSS NECROPSY AND HISTOPATHOLOGY
- Gross necropsy and histopathology was carried out on testes, seminal vesicles, epididymidis, prostate, ovaries uterus, vagina, kidneys, lungs heart, liver, spleen, stomach, thyroid, pituitary glands, adrenal glands, spinal cord and brain.

Statistics:

Parental, maternal, and pup incidence data3 were analyzed using the variance test for homogeneity of the binomial distribution (Snedecor and Cochran, 1967).
Body weights and feed consumption data, organ weight data, and litter averages for pup body weight and percentage male pups were analyzed using Bartlett's test of homogeneity of variances (Sokal and Rohif, 1969) and the
analysis of variance (Snedecor and Cochran, 1967), when appropriate [i.e., Bartlett's test was not significant (p > 0.05)]. If the analysis of variance was significant (p ,,;;; 0.05), Dunnett's test (Dunnett, 1955) was used to identify
the statistical significance of the individual groups. If the analysis of variance was not appropriate [i.e., Bartlett's test was significant (p ,,;;; 0.05)), the Kruskal-Wallis test (Sokal and Rohif, 1969) was used. If there were greater than 75% ties, then Fisher's exact test was used (Siegel, 1956). In cases where the Kruskal-Wallis test was statistically significant (p,,;;; 0.05), Dunn's method of multiple comparisons (Dunn, 1964) was used to identify the statistical
significance of the individual groups.
Count data obtained at natural delivery were evaluated by the KruskalWallis test (Sokal and Rohlf, 1969). In cases where statistical significance occurred (p,,;;; 0.05), Dunn's method of multiple comparisons (Dunn, 1964)
was used to identify the statistical significance of the individual groups.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

In both P and F1 parental generations, at the high dose level, the following significant clinical effects were observed: rales, gasping, hyperpnoea and irregular breathing. Other clinical effects observed (although not always significant) include, chromorhinorhea, yellow/red-brown perioral substance, bradypnoea, alopecia, excess salivation, abdominal distension, red/brown urine, soft/liquid stools or none at all, paleness, cold to the touch, emaciated appearance and head tilt.

Mortality:

mortality observed, treatment-related

Description (incidence):

At 6 mg/kg/day, P and F1 mortality was increased in both sexes (statistically significant except for P males).

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In P and F1 generation males in the highest dose group, a significant decrease in weight gain was observed throughout the study . Highest dose F0 females also showed a decrease in body weight gain during the premating, gestation and lactation periods. High-dose F1 females also showed some significant decreases in premating body weight.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food consumption in the P and F1 generation males was reduced in the first 3 weeks of the study, but then increased throughout the remainder of the study (increased significantly compared to the control group). A similar effect was also seen with F0 and F1 females in the premating period.

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

In P and F1 high-dose males, F1 females and F1 mid-dose females lesions observed were hyperplasia/hyperkeratosis of the forestomach mucosa, increases of erosion(s), ulcer(s) and haemorrhage of the glandular mucosa and focal hyperplasia of the glandular mucosa. Increases in submucosal inflammation and edema with mononuclear-cell infiltrates were also seen in areas of erosion and ulcers. No effects were seen in reproductive organs

Other effects:

not examined

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Description (incidence and severity):

Administration of doses of acrolein as high as 6 mg/kg/day for 70 consecutive days did not affect the mating performance of either the F0 or F1 generation male rats.
Fertility indices (pregnant rats/rats mated) were similar across all groups. The slight reduction in the fertility index for the high-dose F, males (80.0 versus 88.0% for controls)
is not considered to be related to treatment since it is not statistically significant relative to the control group. There is no dose-response relationship, and the value is within the range for historical controls.4 Similarly, no effects on reproductive
performance were noted for either F0 and Fi female rats. Fertility indices for F0 female rats were also within the ranges observed for controls.

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
At 6 mg/kg/day, P and F1 mortality was increased in both sexes (statistically significant except for P males). In both P and F1 parental generations, at the high dose level, the following significant clinical effects were observed: rales, gasping, hyperpnoea and irregular breathing. Other clinical effects observed (although not always significant) include, chromorhinorhea, yellow/red-brown perioral substance, bradypnoea, alopecia, excess salivation, abdominal distension, red/brown urine, soft/liquid stools or none at all, paleness, cold to the touch, emaciated appearance and head tilt.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
In P and F1 generation males in the highest dose group, a significant decrease in weight gain was observed throughout the study . Highest dose F0 females also showed a decrease in body weight gain during the premating, gestation and lactation periods. High-dose F1 females also showed some
significant decreases in premating body weight.

Food consumption in the P and F1 generation males was reduced in the first 3 weeks of the study, but then increased throughout the remainder of the study (increased significantly compared to the control group). A similar effect was also seen with F0 and F1 females in the premating period.

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
No effect

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
No effects on P and F1 generation male rats. However in F0 females, the reduced F1 pup body weights (high dose group) during the lactation period could be regarded as a reproductive effect but in conclusion this was not considered as a selective reproductive effect of acrolein.

ORGAN WEIGHTS (PARENTAL ANIMALS)
No effects

GROSS PATHOLOGY (PARENTAL ANIMALS)
In P and F1 high-dose males, F1 females and F1 mid-dose females glandular and forestomach lesions were observed.

HISTOPATHOLOGY (PARENTAL ANIMALS)
In P and F1 high-dose males, F1 females and F1 mid-dose females lesions observed were hyperplasia/hyperkeratosis of the forestomach mucosa, increases of erosion(s), ulcer(s) and haemorrhage of the glandular mucosa and focal hyperplasia of the glandular mucosa. Increases in submucosal inflammation and edema with mononuclear-cell infiltrates were also seen in areas of erosion and ulcers. No effects were seen in reproductive organs

Effect levels (P0)

1

Dose descriptor:

NOAEL

Effect level:

1 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: paternal (F0 and F1) based on stomach lesion and decreased body wheight gains

2

Dose descriptor:

NOAEL

Effect level:

> 6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: no reproductive effects were observed

Remarks on result:

other: Generation: P and F1 (migrated information)

3

Key result

Dose descriptor:

NOAEL

Effect level:

6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Reduction in body weights for F1 during lactation period at 6 mg/kg, but not considered as a selective reproductive effect of acrolein

Remarks on result:

other: Generation: P and F1 (migrated information)

Target system / organ toxicity (P0)

Key result

Critical effects observed:

no

Results: P1 (second parental generation)

General toxicity (P1)

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Results: F1 generation

General toxicity (F1)

Clinical signs:

not specified

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Details on results (F1)

VIABILITY (OFFSPRING)
No effects
BODY WEIGHT (OFFSPRING)
F1 pup weights were significantly reduced in the high-dose group.
GROSS PATHOLOGY (OFFSPRING)
No effects
HISTOPATHOLOGY (OFFSPRING)
No effects

Effect levels (F1)

1

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: paternal (F0 and F1) based on stomach lesion and decreased body wheight gains

2

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Reduced bodyweights during lactation at 6 mg/kg/day, not considered as a selective reproductive effect of acrolein

Target system / organ toxicity (F1)

Key result

Critical effects observed:

no

Overall reproductive toxicity

Key result

Reproductive effects observed:

no

Any other information on results incl. tables

Allyl methacrylate will be hydrolyzed into allyl alcohol and methacrylic acid. Acrolein is a major toxic metabolite of allyl alcohol and therewith of allyl methacrylate.

Molecular weights:

Allyl methacrylate: 126.16 g/mole

Acrolein: 56.06 g/mole

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study, the overall reproductive NOAEL is 3 mg/kg/d.

Executive summary:

In a 2 -generation reproduction study in rats, acrolein was administered to 30 animals (Crl:CD (SD)BR strain) per sex and dose group by oral gavage at dose levels of 0, 1, 3 or 6 mg/kg for 70 days in a dosing volume of 5 ml/kg.

In both P and F1 parental generations, at the high dose level, mortality was increased and various clinical signs were observed (hyperpnoea, irregular breathing and other, minor signs). No impairment of reproductive performance on P and F1 generation male rats were observed.

However for F0 females (of the high dose group) reduced F1 pup body weights during the lactation period was not considered as a selective reproductive effect of acrolein.

No significant changes in reproductive organs were seen.

Histopathology findings in P and F1 high-dose males, F1 females and F1 mid-dose females were hyperplasia/hyperkeratosis of the forestomach mucosa, increases of erosions, ulcers and redness of the glandular mucosa and focal hyperplasia of the glandular mucosa. Increases in submucosal inflammation and edema with mononuclear-cell infiltrates were also seen in areas of erosion and ulcers.  Parental NOAEL was 1 mg/kg/day (based on erosions of glandular mucosa and hyperplasia/hyperkreatosis of the forestomach).

Male parental and F1 reproductive NOAEL was > 6 mg/kg/day, female parental and F1 reproductive NOAEL was 6 mg/kg/day and also male and female offspring NOAEL is 6 mg/kg/day as slight reduced body weight gains during lactation are not considered as reproductive effects in this study.