Propiononitrile

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:

10th September 1984 - 12th September 1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1985

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

Deviations:

not specified

GLP compliance:

yes

Type of assay:

mammalian bone marrow chromosome aberration test

Test material

Specific details on test material used for the study:

Purity: 90% (adjusted to 100% for dosing purposes).
Appearance: Brown liquid.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Sprague-Dawley male and female rats were purchased from Charles River Breeding Laboratories (~46-51 days old) and allowed to acclimatise for 19 days prior to the experiment. Animals were housed individually in cages, with water and food available ad libitum. Animals were maintained in 12 hours light and dark cycle, with relative humidity levels monitored throughout the study. Animals were health checked and weights recorded pre-dosing and at 22 and 46 hours, just prior to administration of colchicine. Observations of clinical signs of toxicity were recorded twice daily. Animals were sacrificed by carbon dioxide asphyxiation.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

Corn oil

Details on exposure:

The substance was administered via oral gavage.

Duration of treatment / exposure:

Single dose followed by sacrifice at 6, 24 and 48 hours post-exposure.

Frequency of treatment:

Single dose

Post exposure period:

6, 24 and 48 hours

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

100 mg/kg bw/day (nominal)

Remarks:

Male rats

Doses / concentrations 3

Dose / conc.:

200 mg/kg bw/day (nominal)

Remarks:

Female rats

No. of animals per sex per dose:

5

Control animals:

yes

Positive control(s):

Cyclophosphamide

Examinations

Tissues and cell types examined:

Bone marrow cells

Details of tissue and slide preparation:

50 metaphase cells were examined from each rat

Evaluation criteria:

Number and types of chromosomal aberrations, mitotic index, chromosome number per metaphase, and location of each metaphase with chromosomal damage.

Statistics:

The mean mitotic indices, mean chromosome numbers, percent aberrant cells and the mean number of aberrations per cell for each group were statistically compared using the Kruskal-Wallis non-parametrical analysis of variance and nonparametric pairwise group comparisons.
Body weight data was analysed by analysis if variance (ANOVA).
All tests were evaluated at the one-tailed confidence interval (P 0.05).

Results and discussion

Test results

Test results 1

Key result

Sex:

male

Genotoxicity:

negative

Toxicity:

yes

Remarks:

Weight loss at 48 h, depressed activity, red stains on nose/eyes, wheezing, urine stains on coat and soft feces.

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Sex:

female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

Three females died prior to sacrifice after the administered dose of 200 mg/kg. Weight loss at 24 and 48 h, depressed activity, red stains on nose/eyes, wheezing, urine stains on coat and soft feces.

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

There was no significant increase in the frequency of chromosomal aberrations compared to the control values was seen in the groups administered with the substance.

There were no statistically significant differences between the mean chromosome numbers of the test group and the vehicle control.

There were no statistically significant differences between the mean mitotic indices of the test group and the vehicle control animals.

Cytogenic analysis. Summary of Aberration data- 6 hour sacrifice.

Group number	Treatment	Number of animals analysed/group	Number of metaphases analysed/group	Number of aberrant cells/group	% Aberrant cells/group	Statistical significance	Toatal number of aberrations/group	Mean aberrations/cell	Statistical significance
1	Corn oil	10	500	1	0.20	-	1	0.002	-
3	100 mg/kg (male)	5	250	1	0.40	NS	1	0.004	NS
4	200 mg/kg (female)	5	250	1	0.40	NS	1	0.004	NS

Cytogenic analysis. Summary of Aberration data- 24 hour sacrifice.

Group number	Treatment	Number of animals analysed/group	Number of metaphases analysed/group	Number of aberrant cells/group	% Aberrant cells/group	Statistical significance	Toatal number of aberrations/group	Mean aberrations/cell	Statistical significance
1	Corn oil	10	475	0	0.00	-	0	0.000	-
2	Cyclophosphamide (40 mg/kg)	10	192	49	25.52	S	269	1.40	S
3	100 mg/kg (male)	5	250	1	0.40	NS	1	0.004	NS
4	200 mg/kg (female)	5	250	1	0.40	NS	1	0.004	NS

Cytogenic analysis. Summary of Aberration data- 48 hour sacrifice.

Group number	Treatment	Number of animals analysed/group	Number of metaphases analysed/group	Number of aberrant cells/group	% Aberrant cells/group	Statistical significance	Toatal number of aberrations/group	Mean aberrations/cell	Statistical significance
1	Corn oil	10	500	0	0.00	-	0	0.000	-
3	100 mg/kg (male)	5	232	0	0.00	-	0	0.000	-
4	200 mg/kg (female)	2	100	0	0.00	-	0	0.000	-

Chromosome number- 6 hour sacrifice.

Group number	Mean chromosome number	Standard deviation	Statistical significance
1. Corn oil	41.81	0.53	NS
3. 100 mg/kg (male)	41.80	0.038	NS
4. 200 mg/kg (female)	41.77	0.054	NS

Chromosome number- 24 hour sacrifice.

Group number	Mean chromosome number	Standard deviation	Statistical significance
1. Corn oil	41.75	0.43	-
2. Cyclophosphamide (40 mg/kg)	41.63	0.193	NS
3. 100 mg/kg (male)	41.74	0.086	NS
4. 200 mg/kg (female)	41.78	0.055	NS

Chromosome number- 48 hour sacrifice.

Group number	Mean chromosome number	Standard deviation	Statistical significance
1. Corn oil	41.83	0.073	-
3. 100 mg/kg (male)	41.84	0.030	NS
4. 200 mg/kg (female)	41.83	0.071	NS

Mitotic index- 6 hour sacrifice.

Group number	Mean mitotic index	Standard deviation	Statistical significance
1. Corn oil	1.24	0.692	-
3. 100 mg/kg (male)	0.52	0.335	NS
4. 200 mg/kg (female)	1.20	0.648	NS

Mitotic index- 24 hour sacrifice.

Group number	Mean mitotic index	Standard deviation	Statistical significance
1. Corn oil	1.20	0.754	-
2. Cyclophosphamide (40 mg/kg)	0.28	0.193	S
3. 100 mg/kg (male)	1.60	0.400	NS
4. 200 mg/kg (female)	1.72	1.942	NS

Mitotic index- 48 hour sacrifice.

Group number	Mean mitotic index	Standard deviation	Statistical significance
1. Corn oil	2.48	1.734	-
3. 100 mg/kg (male)	2.40	1.744	NS
4. 200 mg/kg (female)	1.30	0.141	NS

S = significant;

NS = not significant.

Applicant's summary and conclusion

Conclusions:

The substance is considered not to be clastogenic.

Executive summary:

The substance was evaluated for clastogenic potential as measured by increases in numerical and structural chromosome aberrations in bone marrow cells in rats. A single dose of the substance was administered by oral gavage to two groups of 15 male rats each at levels of 0 and 100 mg/kg bw and two groups of 15 female rats each at levels of 0 and 200 mg/kg bw. Five males and five females from each group were scheduled to be sacrificed at approximately 6, 24 and 48 hours post-dosing. The results show that no statistically significant increases in the frequency of chromosomal aberrations compared to control values were observed following exposure to the substance. No statistically significant differences were seen between the mean chromosomal numbers and the mean mitotic indices of the test groups and the vehicle controls. Therefore, under the conditions of this study, the substance is considered not to be clastogenic.