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Toxicological information

Genetic toxicity: in vivo

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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:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA OTS 798.5395 (In Vivo Mammalian Cytogenics Tests: Erythrocyte Micronucleus Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 4-vinylcyclohexene
- Batch No: #1
- Supplied by: Union Carbide Corporation, Institute, WV, USA
- Analytical purity: 99.8 (supplied), 99.6-99.7% (reanalysis)
- 4-tertbutylcatechol present as inhibitor

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding laboratories (B6C3F1/CrlBR)
- Age at study initiation: approximately 5 weeks
- Weight at study initiation: 16-25 g (males), 13-20 g (females) at approximately 24 days old
- Assigned to test groups randomly: using a computerised, stratified randomisation program
- Fasting period before study: no
- Housing: individually housed in in stainless steel wire-mesh cages (except during exposure)
- Diet: Purina Certified Rodent Chow (chunk) #5002 ad libitum (except during exposure)
- Water: tap water ad libitum (except during exposure)
- Quarantine period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: target 23±2°C
- Humidity: target 55±15%
- Air changes (per hr): no data
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: 26 January 1993 to 28 May 1993

Administration / exposure

Route of administration:
inhalation
Vehicle:
air
Details on exposure:
TYPE OF INHALATION EXPOSURE: whole body

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: stainless steel and glass with a nominal volume of 150 or 300 L
- Method of holding animals in test chamber: within stainless steel cage modules inside the exposure chamber
- System of generation: The exposure chambers operated in a one-pass, flow-through mode. VCH was vaporised by metering VCH into a glass heated flask. The vapour produced was diluted with filtered air to give the desired concentrations for each of the 4 VCH chambers.
- Temperature, humidity, pressure in air chamber: target of 23±2°C, 40-60%, pressure not reported
- Air flow rate: approximately 40 L/min for the 150 l chambers and 60-70 L/min for the 300 L chambers
- Method of particle size determination: not applicable
- Treatment of exhaust air: Passed through a carbon bed prior to venting through a roof exhaust system

TEST ATMOSPHERE
- Brief description of analytical method used: GC-FID (at approximately 30 min intervals throughout exposure)
- Samples taken from breathing zone: yes
Duration of treatment / exposure:
13 week
Frequency of treatment:
6hours/day, 5 days/week
Post exposure period:
approximately 24 hours
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
0, 50, 250, 1000 ppm
Basis:
other: target concentration
Remarks:
Doses / Concentrations:
0, 53 (9.7), 250 (27), 1000 (80) ppm
Basis:
analytical conc.
(SD)
No. of animals per sex per dose:
5
Control animals:
yes, sham-exposed
Positive control(s):
1,3-butadiene
- Route of administration: whole body inhalation
- Doses / concentrations: 1000 ppm
- Analytical purity: 99.9% (composition unchanged over course of study)
- 4-tertbutylcatechol present as inhibitor

Examinations

Tissues and cell types examined:
bone marrow erythrocytes
Details of tissue and slide preparation:
TREATMENT AND SAMPLING TIMES (in addition to information in specific fields): Mice killed by CO2 inhalation and bone marrow smears prepared from the femurs.

DETAILS OF SLIDE PREPARATION: at least 2 slides/animal, fixed in methanol, stained with acridine orange in phosphate buffer (pH7.4)

METHOD OF ANALYSIS: Cell preparations examined with incident light fluorescence microscopy.
Evaluation criteria:
Proportion of PCEs out of 1000 erythrocytes (PCE frequency) and proportion of MN PCEs among 1000 PCEs (MN frequency) determined.
Statistics:
Data transformed using arcsin square root transformation. Normal distribution - parametric methods used, if not - non-parametric methods (Kruskal-Wallis and Mann-Whitney U tests used).

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Vehicle controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Mortality, clinical signs and bodyweight: At 1000 ppm all males and three females died. Tremors and lethargy present in 1 male and 2 females at 50 ppm but no clinical signs at 250 ppm. Statistically significant decrease in bodyweight gain in females at 250 ppm over duration of study.

 

Micronucleus assessment: No statistically significant reductions in PCE frequency nor any increases in MN frequency in any 4-vinylcyclohexene groups compared to controls. There was a statistically significant increase in MN frequency in the positive control group.

 

Mean PCE frequency

Concentration(ppm)

Mean PCE frequency % (SD)

Males

Females

0

55.1 (49.8, 60.3)

59.8 (48.5, 70.6)

50

57.5 (47.8, 66.9)

59.4 (50.4, 68.1)

250

54.9 (49.6, 60.1)

60.2 (53.2, 67.1)

1000

no data

63.2 (47.5, 77.5)

Positive control (1000 ppm 1,3-butadiene)

61.1 (48.1, 73.4)

72.3 (64.8, 79.2)

 

Mean MN PCE frequency

Concentration(ppm)

Mean MN PCE frequency % (SD)

Males

Females

0

0.14 (0.00, 0.50)

0.10 (0.00, 0.35)

50

0.24 (0.12, 0.41)

0.14 (0.01, 0.43)

250

0.33 (0.12, 0.66)

0.23 (0.11, 0.39)

1000

no data

0.19 (0.00, 3.58)

Positive control (1000 ppm 1,3-butadiene)

1.56 (0.24, 3.98)

1.67 (1.29, 2.10)

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
4-vinylcyclohexene did not cause any apparent physiological or toxic effects on the bone marrow or induce chromosomal or spindle damage in the nucleated erythroblast cells.
Executive summary:

In a mouse micronucleus assay, 4-vinylcyclohexene did not cause any apparent physiological or toxic effects on the bone marrow or induce chromosomal or spindle damage in the nucleated erythroblast cells.