Sodium acrylate

Toxicity to reproduction

Administrative data

Endpoint:

one-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Reference 2

Reference Type:

publication

Title:

Subchronic and Reproductive Toxicology Studies on Acrylic Acid in the Drinking Water of the Rat.

Author:

DePass LR et al.

Year:

1983

Bibliographic source:

Drug and Chemical Toxicology 6: 1-20

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]

Principles of method if other than guideline:

10 male and 20 female rats per group were administered acrylic acid at dosage goals of 0, 83, 250 and 750 mg/kg bw/day in drinking water. At the end of 13 weeks, the male and female rats from each group were mated one male to two females for a 15-day period. Females were introduced into male cages. Rats ware assigned to treatment groups using a computer generated random number scheme. The F0 generation rats were sacrificed after weaning of the F1 generation and were approximately 194 days old at the time of sacrifice. The F1 generation rats were sacrificed at 21 days of age. Treatment effects were determined by statistical comparison of mortality, body weight change, food and water consumption, organ weight change and histological evaluation of tissues from sacrificed animals.

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Acrylic acid

EC Number:

201-177-9

EC Name:

Acrylic acid

Cas Number:

79-10-7

Molecular formula:

C3H4O2

IUPAC Name:

acrylic acid

Specific details on test material used for the study:

- Name of test material (as cited in study report): Acrylic acid
- Analytical purity: 97.8%
- Lot No.: 42-19

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Microbiological Associates, Inc., Walkersville, MD.
- Age at study initiation: (P): 41 days
- Weight at study initiation: (P) Males: 111-139 g; Females: 85-118 g
- Housing: During mating, two females were placed in a cage with one male; at this time all rats received acrylic acid at the concentration in the water for the respective female groups. Fifteen days after the first mating, cohabitation was discontinued and the individual females were placed in plastic cages fitted with wire rod metal tops. Ab-sorb-dri hardwood chips were used for bedding in the plastic cages.
- Diet (ad libitum): Zeigler Brothers NIH-07
- Water (ad libitum): Tap water

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Photoperiod (hrs dark / hrs light): no data

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

water

Details on mating procedure:

- M/F ratio per cage: 1/2
- Length of cohabitation: 15 days
- After successful mating each pregnant female was caged (how): Fifteen days after the first mating, cohabitation was discontinued and the individual females were placed in plastic cages fitted with wire rod metal tops.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability of aqueous solutions of acrylic acid was determined using a gas chromatographic procedure. The mean dosage levels attained were quite close to the dosage goals for each group. The mean overall dosages of acrylic acid were 0.73, 0.25 and 0.085 g/kg bw/day for males and 0.72, 0.25 and 0.083 g/kg bw/day for females.

Duration of treatment / exposure:

Exposure period: 13 weeks
before the mating and afterwards during the gestation and lactation periods.
Premating exposure period (males): 13 weeks
Premating exposure period (females): 13 weeks
Duration of test: approx. 6 months

Frequency of treatment:

continuously

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

83 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

250 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

750 mg/kg bw/day (nominal)

No. of animals per sex per dose:

10 males and 20 females

Control animals:

yes, concurrent vehicle

Positive control:

none

Examinations

Parental animals: Observations and examinations:

DETAILED CLINICAL OBSERVATIONS:
Daily observation for clinical signs

BODY WEIGHT:
Individual body weights for each F0 animal were determined weekly.

FOOD CONSUMPTION:
The food consumption rate was recorded weekly. Fresh diet was added to the jars every week.

WATER CONSUMPTION:
The water consumption rate was recorded weekly. Fresh solutions were prepared each week, with the percentage of acrylic acid in the water (X) adjusted to maintain a relatively constant dosage level (K) in g/kg according to formula:

X = 100 KW / G

Where X and K are explained above:
W = predicted mean body weight, kg
G = mean water consumption, mL

Oestrous cyclicity (parental animals):

not examinated

Sperm parameters (parental animals):

not examinated

Litter observations:

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, physical or behavioural abnormalities.

Postmortem examinations (parental animals):

SACRIFICE
Five male and five female rats, randomly selected from each dosage level of the F0 parents, were anesthetized with methoxyflurane and sacrificed by severing the brachial vesseis to permit exsanguination.

GROSS NECROPSY
- All sacrificed rats were given a complete gross necropsy examination and organ weights were recorded for the liver, kidneys, heart, spleen, brain and testes.

HISTOPATHOLOGY / ORGAN WEIGHTS
The following tissues were taken and fixed in 10% neutral buffered formalin, processed for paraf in embedding, sectioned at 5 microns and stained with hematoxylin and eosin on all high dose and control animals. Only those tissues with gross lesions were examined microscopically from the intermediate and low level animals.
Pituitary, thyroids, parathyroids, adrenals, heart, thymus, spleen, testes, epididymides, kidneys, urinary bladder, tongue, submandibular salivary gland, esophagus, stomach, duodenum, colon, mesenteric lymph node, nasal cavity, trachea, lungs, ovaries, oviduct, liver, pancreas, brain, eyes, skin, mammary gland, sternum, any lesions.

Postmortem examinations (offspring):

SACRIFICE
Five male and five female rats, randomly selected from each dosage level of the F1 weanlings, were anesthetized with methoxyflurane and sacrificed by severing the brachial vesseis to permit exsanguination.

GROSS NECROPSY
- All sacrificed rats were given a complete gross necropsy examination and organ weights were recorded for the liver, kidneys, heart, spleen, brain and testes.

HISTOPATHOLOGY / ORGAN WEIGHTS
The following tissues were taken and fixed in 10% neutral buffered formalin, processed for paraf in embedding, sectioned at 5 microns and stained with hematoxylin and eosin on all high dose and control animals. Only those tissues with gross lesions were examined microscopically from the intermediate and low level animals.
Pituitary, thyroids, parathyroids, adrenals, heart, thymus, spleen, testes, epididymides, kidneys, urinary bladder, tongue, submandibular salivary gland, esophagus, stomach, duodenum, colon, mesenteric lymph node, nasal cavity, trachea, lungs, ovaries, oviduct, liver, pancreas, brain, eyes, skin, mammary gland, sternum, any lesions.

Statistics:

For every experimental parameter or index measured, the results of each of the three test levels were compared with the control group. To evaluate the statistical significance of possible changes in continuous data, the analysis of variance (ANOVA) validated by Bartlett's test for homogeneity of variance, was used. Individual mean differences were identified by Duncan's multiple range test when indicated by a significant F value for ANOV. In the case of heterogeneous variances, as indicated by Bartlett's test, the paired group F test, and either the Cochran or the Student t-test were used to identify significant differences. Enumerative data were evaluated statistically by NXR Chi Square test; differences between groups were delineated by Fisher's Exact test. Non-parametric data were compared by a distribution-free multiple comparison method. The fiducial limit of 0.05 was employed as the critical level of difference not attributable to chance

Reproductive indices:

The following reproductive parameters were evaluated statistically:
1. Fertility index - the proportion of females that were pregnant of the number that were mated or the proportion of the males shown to be fertile of the number that were mated.
2. Gestation Index - the proportion of pregnancies that resulted in litters with live pups.
3. Gestation Survival Index - the proportion of newborn pups that were alive at birth.
4. Pups born alive per litter.
5. Days from mating to litter.

Offspring viability indices:

The following reproductive parameters were evaluated statistically:
1. 5-Day Survival Index - the proportion of liveborn that survived 5 days.
2. 21-Day Survival Index - the proportion of pups retained on day 5 that survived 21 days.
3. Pups weaned per pups alive at birth.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Description (incidence and severity):

There were no significant abnormal clinical signs observed.

Mortality:

no mortality observed

Description (incidence):

No deaths occurred during the study.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight gain was depressed markedly for both sexes at the high dosage level. This effect was statistically highly significant in these groups throughout the study. At the highest dosage level there were effects on diet and water consumption, body weight gain and organ weights (liver, kidneys, spleen, testes, brain). At the intermediate dosage level, a decrease in water consumption was noted for both sexes. Body weight gain was reduced while liver and kidney weights (absolute and/or relative) were increased for the female rats. At the lowest dosage level, absolute liver and kidney weights and relative liver weights were increased for the females. These changes were possibly chemically induced.

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:

no effects observed

Description (incidence and severity):

Histopathological examination revealed no treatment-related lesions associated with the ingestion of acrylic acid.

Other effects:

effects observed, treatment-related

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, treatment-related

Description (incidence and severity):

At the highest dose, a numerical reduction of the fertility (male and female) and gestation indices, pups born alive and pups weaned was observed.

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Effect level:

83 mg/kg bw/day

Sex:

male/female

Basis for effect level:

body weight and weight gain

organ weights and organ / body weight ratios

2

Key result

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day

Sex:

male/female

Basis for effect level:

reproductive performance

Target system / organ toxicity (P0)

Critical effects observed:

not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Description (incidence and severity):

There were no significant abnormal clinical signs observed. There were no consistent findings in the spontaneous death of neonatal rats.

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

The effects at the highest dosage level of the parent generation were similar to those observed for the highest dosage level of the progeny. Here also, there were effects on body weight gain and organ weights (liver, heart, kidneys, brain, spleen).

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no gross lesions which could be attributed to treatment with acrylic acid.

Histopathological findings:

no effects observed

Description (incidence and severity):

Histopathological examination revealed no treatment-related lesions associated with the ingestion of acrylic acid.

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

250 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: Pup body and organ weights; number of pups born alive and pups weaned

Target system / organ toxicity (F1)

Critical effects observed:

not specified

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Mean body weight changes (g)

Week of treatment	0 mg/kg/bw/d		83 mg/kg/bw/d		250 mg/kg/bw/d		750 mg/kg/bw/d
	male	female	male	female	male	female	male	female
Mean bw at day 0	124.5	99.4	124.0	101.3	125.3	102.4	121.4	99.0
1	29.8	12.7^x	28.6	14.2	31.2	13.8^x	24.1^a	10.6^a
2	62.2	26.8	56.8	27.6	63.1	23.5^a	51.3^b	21.4^c
3	89.2	37.6	83.4	38.1	91.7	36.6	75.7^b	30.0^c
4	112.2	47.6	106.5	46.7	111.1	45.4	93.6^b	36.9^c
5	130.3	55.6	126.7	55.8	128.6	52.5	106.7^b	41.6^c
6	145.3	63.6	142.2	63.8	141.8	58.6^a	119.0^c	47.2^c
7	159.5	69.4	154.2	70.3	153.0	63.6^a	127.8^c	49.8^c
8	171.8	73.3	167.7	74.1	162.6	67.1^a	125.6^c	52.1^c
9	181.1	75.9	176.4	77.2	170.1	69.2^a	131.6^c	53.0^c
10	191.4	79.9	187.6	81.0	180.0	73.3^a	139.2^c	55.2^c
11	200.1	82.4	194.9	83.3	185.4	74.5^b	142.8^c	57.4^c
12	205.2	84.4	200.6	86.0	191.7	78.0^a	144.7^c	58.6^c

^a0.05>p>0.01

^b0.01>P>0.001

^cP<0.001

^xOne clinically ill rat excluded from statistical evaluation of body weight gain.

Reproductive Performance

Parameter	Dose (mg/kg/bw/d)
	0	83	250	750
Fertility index (males)^a	80	100	80	60
Fertility index (female)^b	50	95	75	45
Gestation index^c	100	100	100	89
Gestation survival index^d	100	100	100	100
5-Day survival index^e	100	100	100	100
21-Day survival index^f	100	100	100	100
Pups born alive/Litter^g	6	8	9	4
Pups weaned/Pups alive at birth (100)^g	100	100	100	42

 ^aLitters sired per males mated x 100

^bDeliveries per females mated x 100

^cLitters with live pups/total pregnancies x 100

^dPups born viable/total pups delivered x 100, median per litter

^ePups viable at day 5/pups born viable x 100, median per litter

^fPups viable on day 21/pupe retained at day 5 x 100, median per litter

^gMedians