spirodiclofen (ISO);3-(2,4-dichlorophenyl)-2-oxo-1-oxaspiro[4.5]dec-3-en-4-yl 2,2-dimethylbutyrate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: 92/69/EEC

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5395 (In Vivo Mammalian Cytogenetics Tests: Erythrocyte Micronucleus Assay)

Version / remarks:

not specified

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian erythrocyte micronucleus test

Test material

Test material information

1

Reference substance name:

3-(3,5-Dichlorophenyl)-2-oxo-1-oxaspiro[4.5]dec-3-en-4-yl 2,2-dimethylbutanoate

Cas Number:

148477-71-8

Molecular formula:

C21H24Cl2O4

IUPAC Name:

3-(3,5-Dichlorophenyl)-2-oxo-1-oxaspiro[4.5]dec-3-en-4-yl 2,2-dimethylbutanoate

Test material form:

not specified

Test animals

Species:

mouse

Strain:

NMRI

Details on species / strain selection:

Standard laboratory species/strain

Sex:

male/female

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

0.5% aqueous Cremophor emulsion

Details on exposure:

Male and female mice received a single intraperitoneal administration of 800 mg/kg bw.

Duration of treatment / exposure:

Single intraperitoneal injection, with sampling at 16, 24 and 48 hours.

Frequency of treatment:

Single dose

Post exposure period:

The femoral marrow of groups was prepared 16, 24 and 48 hours after administration. Negative and positive controls were sacrificed 24 hours after administration.

Doses / concentrations

Dose / conc.:

800 mg/kg bw/day (actual dose received)

Remarks:

intraperitoneal administration

No. of animals per sex per dose:

20/sex

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide served as positive control; the dose was 20 mg/kg bw ip.

Examinations

Tissues and cell types examined:

Femoral bone marrow: polychromatic erythrocytes (PCEs)

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:

After single intraperitoneal administration of 800 mg/kg bw, mice showed the following signs until sacrifice: apathy, roughened fur, spasm and eyelids stuck together. Their feeding behaviour
was normal. One of forty treated animals died during the test period. No symptoms were recorded for the control groups. No animals died in these groups.

The ratio of polychromatic to normochromatic erythrocytes was clearly altered by treatment with spirodiclofen at all time points.

No biologically or statistically significant variations existed between the negative control and the groups treated intraperitoneally with 800 mg/kg bw spirodiclofen with respect to the
incidence of micronucleated polychromatic erythrocytes.

Any other information on results incl. tables

Summary of the mouse bone marrow micronucleus assay with spirodiclofen

Group	Time point
	16h		24h		48h
	NCE:PCE^1	MnPCE^2	NCE:PCE^1	MnPCE^2	NCE:PCE^1	MnPCE^2
Vehicle control	-	-	942	1.8	-	-
800 mg/kg bw	2501	1.4	2166	1.9	2035	1.9
Positive control	-	-	913	16.4	-	-

¹ number of NCEs per 1000 PCEs

² number of micronuclei/1000 PCEs

Applicant's summary and conclusion

Conclusions:

This study showed no evidence of micronucleus formation in the bone marrow of mice, with evidence of target tissue exposure.

Executive summary:

Spirodiclofen was tested for clastogenic potential in the bone-marrow erythroblasts of male and female mice. Male and female mice received a single intraperitoneal administration of 800 mg/kg bw.  The femoral marrow of groups were prepared 16, 24 and 48 hours after administration. Negative and positive controls were sacrificed 24 hours after administration. Cyclophosphamide served as positive control, the dose was 20 mg/kg bw ip.  Spirodiclofen-treated mice displayed clinical signs including rough fur, apathy, spasms and eyelids stuck together; one mouse died. The PCE:NCE ratio was altered by treatment with spirodiclofen, demonstrating target tissue exposure.  The incidence of micronucleated was unaffected by treatment with spirodiclofen.  The positive control cyclophosphamide had a clear clastogenic effect, an increase in polychromatic erythrocytes with micronuclei, and thus proved the sensitivity of this test system.  Spirodiclofen was therefore not clastogenic under the conditions of this assay. Conclusion: This study did not reveal evidence of a clastogenic effect of spirodiclofen in an in vivo system in mice.