1,2-epoxycyclohexane

Genetic toxicity: in vivo

Administrative data

Endpoint:

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

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

08/23/1994 (start date)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: A non-GLP study performed to sound scientific principles with a sufficient level of detail to assess the quality of the submitted data.

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Year:

1994

Report date:

1994

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

Deviations:

yes

Remarks:

Deviations from guideline - separation of split dose treatment.

Principles of method if other than guideline:

Deviations from guideline - separation of split dose treatment.
Not mentioned - details on animals and environmental conditions.

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

1,2-epoxycyclohexane

EC Number:

206-007-7

EC Name:

1,2-epoxycyclohexane

Cas Number:

286-20-4

Molecular formula:

C6H10O

IUPAC Name:

7-oxabicyclo[4.1.0]heptane

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): cyclohexene oxide

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male

Details on test animals or test system and environmental conditions:

No further information on test animals and environmental conditions.

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

Corn oil

Details on exposure:

no data

Duration of treatment / exposure:

Injections at 3 and 72 hours.

Frequency of treatment:

Injections at 3 and 72 hours.

Doses / concentrations

Remarks:

Doses / Concentrations:
19.5, 39.06, 78.13, 156.25, 312.5, 625 and 1250 mg/kg
Basis:
nominal conc.

No. of animals per sex per dose:

5 males per dose.

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide
Dose: 10 mg/kg
No. test animals: 5

Examinations

Tissues and cell types examined:

Erythrocytes in the bone marrow of the femurs.

Details of tissue and slide preparation:

- Animals were euthanized by CO2 inhalation and the femurs were removed.
- The bone marrow was flushed from the femurs and spread onto slides.
- The slides were air-dried, fixed, and stained with a fluorescent DNA-specific stain that easily illuminated any micronuclei that may be present.

Evaluation criteria:

- Typically, 2000 polychromatic erythrocytes (PCEs, reticulocytes; immature erythrocytes) were scored per animal for frequency of micronucleated cells in each of test animals.
- In addition, the percentage of PCEs among the total erythrocyte population in the bone marrow was scored for each dose group as an indicator of chemically-induced toxicity.
- In non-treated healthy rats, the %PCE in bone marrow is usually around 50-60%.
- If a chemical interferes with the production of erythrocytes in the bone marrow, then the %PCE in the bone marrow may decline from the typical normal level.
- Conversely, if erythrocyte production is stimulated by chemical exposure, then a higher percentage of immature erythrocytes may be observed.

Statistics:

A formal statistical analysis of the data was performed that includes a trend test, to determine if there was an overall increase across all doses in the frequency of cells containing micronuclei, and a pairwise comparison of each dose group to the corresponding control, to see if any one dose group was statistically different from the control group in frequency of micronucleated cells.

- A positive trend test is one in which the P value is equal to or less than 0.025.
- For the slide-based micronucleus data, the micronucleus frequency in any dose group is considered significantly elevated over the control group if the P value is equal to or less than 0.025 divided by the number of chemical-treatment groups.

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

not examined

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

All test animals died after receiving 625 and 1250 mg/kg of the test material and one animal died after receiving a dose of 312.5 mg/kg.

Any other information on results incl. tables

		Dose	Animal	Polychromatic Erythrocytes
		(mg/kg)	Number	Trend P = 0.638
				No. Examined	Total MN Cells	Percent PCE	MN Cells
							per 1000
Vehicle Control	CRO	0	1219	2000	2	40	1
		0	1250	2000	0	45	0
		0	1261	2000	3	32	1.5
		0	1620	2000	1	48.5	0.5
		0	1689	2000	2	40	1
Average ± SEM						41.10 ± 2.79	0.80 ± 0.25
Test Material		19.5	1150	2000	3	36	1.5
		19.5	1161	2000	3	40	1.5
		19.5	1220	2000	3	36	1.5
		19.5	1289	2000	5	41	2.5
		19.5	1419	2000	3	38.5	1.5
Average ± SEM						38.30 ± 1.02	1.70 ± 0.20
Pairwise P							0.0358
Test Material		39.06	1121	2000	2	42	1
		39.06	1185	2000	1	51.5	0.5
		39.06	1210	2000	1	39	0.5
		39.06	1235	2000	6	57.5	3
		39.06	1284	2000	7	45.5	3.5
Average ± SEM						47.10 ± 3.33	1.70 ± 0.64
Pairwise P							0.0358
Test Material		78.13	1327	2000	1	42.5	0.5
		78.13	1340	2000	5	40	2.5
		78.13	1382	2000	1	35	0.5
		78.13	1385	2000	4	41	2
		78.13	1390	2000	4	36	2
Average ± SEM						38.90 ± 1.45	1.50 ± 0.42
Pairwise P							0.0721
Test Material		156.25	1205	2000	2	35.5	1
		156.25	1207	2000	4	45	2
		156.25	1226	2000	4	49	2
		156.25	1277	2000	2	42.5	1
		156.25	1279	2000	2	47.5	1
Average ± SEM						43.90 ± 2.37	1.40 ± 0.24
Pairwise P							0.1003
Test Chemical		312.5	1181	2000	3	37	1.5
		312.5	1306	2000	1	35.5	0.5
		312.5	1323	2000	2	30	1
		312.5	1426	2000	3	36	1.5
		312.5	1448^d	0	0	0	0
Average ± SEM						34.63 ± 1.57	1.13 ± 0.24
Pairwise P							0.2403
Test Material		625	1320^d	0	0	N/A	0
		625	1362^d	0	0	N/A	0
		625	1364^d	0	0	N/A	0
		625	1371^d	0	0	N/A	0
		625	1383^d	0	0	N/A	0
Average ± SEM						N/A ± N/A	0.00 ± 0.00
Pairwise P							*
Test Chemical		1250	1105^d	0	0	N/A	0
		1250	1307^d	0	0	N/A	0
		1250	1326^d	0	0	N/A	0
		1250	1377^d	0	0	N/A	0
		1250	1379^d	0	0	N/A	0
Average ± SEM						N/A ± N/A	0.00 ± 0.00
Pairwise P							*
Positive Control	CPA	10	1285	2000	28	40	14
		10	1290	2000	25	26.5	12.5
		10	1363	2000	30	31.5	15
		10	1640	2000	26	32	13
		10	1682	2000	28	37	14
Average ± SEM						33.40 ± 2.34	13.70 ± 0.44
Pairwise P							< 0.0001
Abbreviations:
CRO = Corn Oil
d = dead
* = Insufficient animals scored to calculate p-value.
CPA = Cyclophosphamide

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
The genetic toxicity of the test material was determined to be negative in an in vivo micronucleus study conducted in male Fischer 344 rats.

Executive summary:

The genetic toxicity of the test material was determined to be negative in an in vivo micronucleus study. The study was conducted to a protocol which is similar to the standard guideline OECD 475; there were only minor deviations. Five male Fischer 344 rats per dose were exposed to the test material via intraperitoneal injection. The test material was administered up to the level of toxicity. Under the conditions of the test, the genotoxicity of the test material was determined to be negative.