2-methylglutaronitrile

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

other information

Study period:

No data

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Relevant methodological deficiencies: cytotoxicity not studied, administrated volume was higher than recommended, animals were sacrificed 6 hoursafter the last administration instead of 18-24 hours. Purity and composition not stated.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

yes

Remarks:

: the cytotoxicity is not studied, administrated volume was higher than recommended, animals were sacrificed 6 hours after the last administration instead of 18-24 hours

Principles of method if other than guideline:

Method: described in Boller and Schmid (1970) and Schmid (1975)

GLP compliance:

no

Remarks:

The study was performed before the GLP statement

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

2-methylglutaronitrile

EC Number:

224-923-5

EC Name:

2-methylglutaronitrile

Cas Number:

4553-62-2

Molecular formula:

C6H8N2

IUPAC Name:

2-methylpentanedinitrile

Details on test material:

- Name of test material (as cited in study report): methylglutaronitrile technique
- Physical state: colourless liquid

Test animals

Species:

mouse

Strain:

Swiss

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Carworth Farm Lane-Petter
- Age at study initiation: no data
- Weight at study initiation: 25-30 g
- Assigned to test groups randomly: no
- Fasting period before study: no
- Housing: no data
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
No data

IN-LIFE DATES: no data

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: soluble in water
- Concentration of test material in vehicle: 0.4 and 2 µL/mL
- Amount of vehicle (if gavage or dermal): no data

Details on exposure:

No details

Duration of treatment / exposure:

30 hours

Frequency of treatment:

2 administrations (at 0 and 24 hour)

Post exposure period:

6 hours

Doses / concentrations

Remarks:

Doses / Concentrations:
2 x 0.01 mL/kg bw and 2 x 0.05 mL/kg bw
Basis:
nominal conc.

No. of animals per sex per dose:

10 males per dose

Control animals:

yes, concurrent vehicle

Positive control(s):

Methyl-Methanesulfonate (MMS)
- Justification for choice of positive control(s): MMS is a recognised clastogenic substance
- Route of administration: oral (gavage)
- Doses / concentrations: 2 x 65 mg/kg/bw

Examinations

Tissues and cell types examined:

bone marrow (2000 polychromatic erythrocytes per animal)

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION:
Based on a preliminary study.

DETAILS OF SLIDE PREPARATION:
Bone marrow was collected in calf embryo serum. After centrifugation, the pellet was homogenized, applied to a slide and coloured with May Grünwald-Giemsa.

METHOD OF ANALYSIS:
1000 polychromatic erythrocytes were counted by 2 persons and a mean  value was calculated.

Evaluation criteria:

% of polychromatic erythrocytes with micronuclei

Statistics:

The % of polychromatic erythrocytes with micronuclei in the control and treated groups were compared with the Student t-test.

Results and discussion

Test results

Sex:

male

Genotoxicity:

ambiguous

Toxicity:

not examined

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range:  0,5 mL/kg bw, 0,1 mL/kg bw
- Clinical signs of toxicity in test animals: At 0,5 mL/kg bw,  5/5 animals died 1 hour after the administration. At 0,1 mL/kg, 5/5 animals died 2 hours after the administration. 2x0,05 mL/kg bw is chosen as the highest dose for the definitive study.

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): see Table 7.6.2/1
- Ratio of PCE/NCE (for Micronucleus assay): no data
- Appropriateness of dose levels and route: no data
- Statistical evaluation: no statistically significant increase in the  number of micronuclei was observed in the treated animals.

Any other information on results incl. tables

Table 7.6.2/1: Results of in vivo micronucleus test with methylglutaronitrile technique

Group	Dose	No. of mice	% polychromatic erythrocytes with micronuclei
Control (water)	0	10	0.13 ± 0.05
Methylglutaronitrile technique	2 x 0.01 mL/kg bw	10	0.09 ± 0.02
Methylglutaronitrile technique	2 x 0.05 mL/kg bw	13*	0.11 ± 0.05
Methyl-methanesulfonate	2 x 65 mg/kg bw	10	2.87 ± 0.69

*: At this dose, 3/13 animals died (2 animals 1h after the first administration and 1 animal few minutes after the second administration. This animal was already prostrated at the time of administration).

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): other: Unconclusive
Under the test conditions, no conclusion can be established.

Executive summary:

In a Swiss CFLP mouse bone marrow micronucleus assay, 10 males/dose were treated by oral gavage with methylglutaronitrile technique (purity unknown - see section 1.2) at doses of 2 x 0.01 and 2 x 0.05 mL/kg bw. Bone marrow cells were harvested at 6 hours post-treatment. The vehicle was water.

 

Methylglutaronitrile technique was tested at an adequate dose (based on a preliminary study results). The positive control induced the appropriate response.

Only the percentage of micronuclei in polychromatic erythrocytes is determined and no effects were seen after treatment. However, there is no information concerning proportion of immature erythrocytes among total erythrocytes and the accessibility of the product to the bone marrow. The cytotoxicity of the product is missing. There are several other deviations. Therefore no conclusion can be established based on this study (Kr:3).