Ethanone, 2-chloro-1-(1-chlorocyclopropyl)-

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sept 2002 - Jan 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD 473

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

446-620-9

EC Name:

-

Cas Number:

120983-72-4

Molecular formula:

Hill formula: C5H6Cl2O CAS formula: C5H6Cl20

IUPAC Name:

2-chloro-1-(1-chlorocyclopropyl)ethan-1-one

Test material form:

liquid

Details on test material:

purity: 92.3 %

Specific details on test material used for the study:

purity 93.2%, Identity and stability tested analytically

Method

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Details on mammalian cell type (if applicable):

The karyotype of the V79 cells (modal number of chromosomes: 22) was confirmed on August 9, 2002.

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9 mix

Test concentrations with justification for top dose:

Concentration range in the main test (with metabolic activation): 1 - 8 µg/ml
Concentration range in the main test (without metabolic activation): 0.5 - 4 µg/ml

Details on test system and experimental conditions:

Exposure period (with metabolic activation): 4 hours
Exposure period (without metabolic activation): 4 hours

Expression time:
4 h

Selection time:
Experiment 1: 18 h (with and without metabolic activation)
Experiment 2: 30 h (with and without metabolic activation)

Fixation time:
2 h

Results and discussion

Test results

Test results 1

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(>2 µg/ml)

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(> 7 µg/ml)

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Observations:
The substance showed clear cytotoxic effects. An indirect
cyctoxicity based mutagenic effect may be possible.

Any other information on results incl. tables

Mitotic index without S9 mix: In comparison to the solvent control, the mitotic indices in the treated cultures were relevantly reduced at 2 μg/ml and above. The cultures treated with mitomycin C showed no reduction in mitosis rate.

Mitotic index with S9 mix: In comparison to the solvent control, the treated cultures showed no relevant reduction of the mitosis rate. The positive control cyclophosphamide also reduced the mitosis rate.

Survival index without S9 mix: In comparison to the solvent control, the survival indices in the treated cultures were relevantly reduced at 2 μg/ml and above. The cultures treated with mitomycin C showed a reduction in survival rate.

Survival index with S9 mix: In comparison to the solvent control, the treated cultures showed a relevant reduction of the survival rate at 7 μg/ml and above. The positive control cyclophosphamide also reduced the survival rate.

Chromosome Aberrations

JAU 64 76-Chloromethylketone without S9 mix: Biologically relevant and statistically significant increases of numbers of metaphases with aberrations were detected after 18 or 30 hours culture time. The treatment with the positive control mitomycin C resulted in a clear and statistically significant increase of metaphases with aberrations and demonstrated the sensitivity of the test system.

JAU 64 76-Chloromethylketone with S9 mix: Biologically relevant and statistically significant increases of metaphases with aberrations were detected after total culture times of 18 or 30 hours. The positive control cyclophosphamide induced statistically significant and biologically relevant increases of metaphases with aberrations and demonstrated the sensitivity of the test system and the activity of the used S9 mix.

Applicant's summary and conclusion

Conclusions:

Based on the results of this test, JAU 64 76-Chloromethylketone is considered to be clastogenic for mammalian cells in vitro. Since nucleus disintegration was observed at 2 μg/ml (without S9 mix) and at 8 μg/ml (with S9 mix), an indirect cytotoxicity based effect may be possible.

Executive summary:

The clastogenic potential of JAU 64 76-Chloromethylketone was evaluated in a chromosome aberration test in vitro. lnitially Chinese hamster V79 cells were exposed in the absence of S9 mix for 4 hours to concentrations of 0.5, 1, 2, 3 and 4 μg/ml of JAU 6476-Chloromethylketone. Cultures of all concentrations were harvested 18 hours after the beginning of the treatment. In addition, cells treated with 2, 3 and 4 μg/ml were harvested 30 hours after the beginning of the treatment. In the presence of S9 mix cells were exposed for to concentrations of 1, 3, 6, 7 and 8 μg/ml of JAU 6476 Chloromethylketone. Cultures of all concentrations were harvested 18 hours after the beginning of the treatment. In addition, cells treated with 6, 7 and 8 μg/ml were harvested 30 hours after the beginning of the treatment. Based on their cytotoxicity concentrations were selected for reading of metaphases. Without S9 mix cytotoxic effects were observed at 2 μg/ml and above. With S9 mix cytotoxic effects were observed at 7 μg/ml and above. Precipitation of JAU 6476 -Chloromethylketone in the medium was not observed. Therefore, concentrations of 0.5, 1 and 2 μg/ml JAU 6476-Chloromethylketone were chosen for reading in the absence of S9 mix. In the presence of S9 mix 1, 6 and 8 μg/ml of JAU 6476-Chloromethylketone were employed. All of these cultures harvested 18 hours after the beginning of the treatment were included. In addition, cultures treated in the absence of S9 mix with 2 μg/ml and harvested 30 hours after the beginning of the treatment were used. The same was true for cultures treated in the presence of S9 mix with 8 μg/ml. In the absence and in the presence of S9 mix cultures treated with JAU 6476- Chloromethylketone showed biologically relevant and statistically significant increased numbers of aberrant metaphases. The positive controls mitomycin C and cyclophosphamide induced clastogenic effects and demonstrated the sensitivity of the test system and the activity of the used S9 mix. Based on this test, JAU 64 76-Chloromethylketone is considered to be clastogenic for mammalian cells in vitro. Since nucleus disintegration was observed at 2 μg/ml (without S9 mix) and at 8 μg/ml (with S9 mix), an indirect cytotoxicity based effect may be possible.