acrylic acid, 3-(trimethoxysilyl)propyl ester

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14th November 1994 - 7th December 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The study was conducted according to an older (1981) version of OECD Test Guideline 474, with only a single dose used at the initial sampling time and only 1000 peripheral erythrocytes scored for micronuclei.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

1981

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian bone marrow chromosome aberration test

Test material

Test material information

1

Reference substance name:

-

EC Number:

419-560-6

EC Name:

-

Cas Number:

4369-14-6

Molecular formula:

C9H18O5Si

IUPAC Name:

3-(trimethoxysilyl)propyl prop-2-enoate

Test material form:

liquid

Test animals

Species:

mouse

Strain:

CD-1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd., Manston, Kent
- Age at study initiation: 5-8 weeks old
- Weight at study initiation: males 22-29 g (males, females 20-24 g
- Assigned to test groups randomly: Yes
- Fasting period before study: Not specified
- Housing: In groups of 5 per sex
- Diet (e.g. ad libitum): Rat and Mouse Expanded diet No. 1, ad libitum
- Water (e.g. ad libitum): Mains drinking water, ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-22
- Humidity (%): 51-53
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: Arachis oil
- Justification for choice of solvent/vehicle: Not specified
- Concentration of test material in vehicle: 100 mg/mL
- Dose volume: 10 mL/kg
- Lot/batch no. (if required): 010699
- Purity: Not specified

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test material was freshly prepared as required as a suspension at the appropriate concentration in arachis oil.

Duration of treatment / exposure:

Single intraperitoneal dose

Frequency of treatment:

Single exposure

Post exposure period:

24, 48 or 72 hours

Doses / concentrations

Dose / conc.:

1 000 mg/kg bw (total dose)

No. of animals per sex per dose:

5M, 5F

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide Monohydrate
- Justification for choice of positive control(s): The substance is known to produce micronuclei under the conditions of the test.
- Route of administration: Oral dose
- Doses / concentrations: Dose 50 mg/kg bw; concentration 5 mg/mL; dose volume 10 mL/kg

Examinations

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:
Based on the findings of a dose range-finding study. The dose tested in the micronucleus test was the maximum tolerated dose.

TREATMENT AND SAMPLING TIMES:
Three groups of 5 male and 5 female mice where each animals was dosed via the intraperitoneal route with the test material at 1000 mg/kg bw. One group of mice was killed at 24 hours following the treatment, the second group was killed at 48 hours and the third at 72 hours post-treatment.

DETAILS OF SLIDE PREPARATION:
Immediately following sacrifice (at 24, 48 and 72 hours), one femur was dissected from each animal, aspirated with foetal calf serum and bone marrow smears prepared following centrifugation and re-suspension. The smears were air-dried, fixed in absolute methanol and stained in May-Grunwald/Giemsa.

METHOD OF ANALYSIS:
Stained bone marrow smears were coded and examined blind using light microscopy at x1000 magnification. The incidence of micronucleated cells per 1000 PCEs (blue stained immature cells) per animal was scored. In addition, the NCEs (pink stained mature cells) associated with 1000 polychromatic erythrocytes were counted; these cells are also scored for incidence of micronuclei. The ratio of NCEs to PCEs was calculated together with appropriate group mean values for males and females separately and combined.

Evaluation criteria:

A positive mutagenic response is demonstrated when a statistically significant increase in the number of micronucleated polychromatic erythrocytes is observed for either the 24, 48 or 72-hour kill times. If these criteria are not demonstrated, then the test material is considered to be non-genotoxic under the conditions of the test. A positive response for bone marrow toxicity is demonstrated when the dose group mean normochromatic to poluchromatic ratio is shown to be statistically significant from the concurrent vehicle control group.

Statistics:

All data were statistically analysed, withg group means, standard deviation, and NCE: PCE ratios calculated and statistical significance determined,

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY:
- Dose range: 400, 800, 1250, 2500 mg/kg bw
- Solubility: Not assessed
- Clinical signs of toxicity in test animals: Clinical signs were observed in animals dosed at and above 1250 mg/kg bw and included lethargy, decreased respiratory rate, laboured respiration, ataxia, pallor of the extremities, ptosis and hunched posture. Premature deaths were seen in one animal dosed at 1250 mg/kg bw and in two animals at 2500 mg/kg bw. Since no clinical signs were seen at 800 mg/kg bw and one premature death seen at 1250 mg/kg bw, the dose level selected as the maximum tolerated dose was 1000 mg/kg bw.
- Evidence of cytotoxicity in tissue analyzed: Not specified
- Rationale for exposure: To determine the suitable dose level for the micronucleus study. The dose level selected should be the maximum tolerated dose level or that which produces some evidence of cytotoxicity up to a maximum dose of 5000 mg/kg bw.
- Harvest times: No tissue harvest performed
- High dose with and without activation: The high dose was 2500 mg/kg bw and metabolic activation was not used in the study.

RESULTS OF DEFINITIVE STUDY:
- Types of structural aberrations for significant dose levels (for Cytogenetic or SCE assay): Not specified
- Induction of micronuclei (for micronucleus assay): There was no statistically significant increase in the frequency of micronucleated PCEs in any of the test material dose groups when compared to the control group.
- Ratio of NCE/PCE (for micronucleus assay): There was no statistically significant change in the NCE/PCE ratio in any of the test material dose groups when compared to their concurrent controls, although the presence of clinical signs indicated that systemic absorption had occurred.
- Appropriateness of dose levels and route: Premature deaths were seen for one animal at 48 hours and two at 72 hours. Clinical signs were seen in the dosed animals and included lethargy, decreased respiratory rate, laboured respiration, ataxia and tiptoe gait.
- Statistical evaluation: No statistically significant changes were seen in the dosed groups.

Applicant's summary and conclusion

Conclusions:

3-(Trimethoxysilyl)propyl acrylate has been tested for its ability to induce micronuclei in vivo in male and female CD-1 mice in a study conducted according to OECD Test Guideline 474 and in compliance with GLP (reliability score 2). There was no statistically significant increase in the frequency of micronucleated PCEs in any of the test material dose groups when compared to the control group. There was no statistically significant change in the NCE/PCE ratio in any of the test material dose groups when compared to their concurrent controls, although the presence of clinical signs indicated that systemic absorption had occurred. Appropriate negative (treatment medium) and positive controls were included and gave expected results. It is concluded that the test substance is negative for the induction of micronuclei under the conditions of this in vivo study.