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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1980-01-28 to 1980-03-27
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was conducted according to a test protocol that is comparable to the appropriate OECD test guideline with acceptable restirictions. The restrictions were that only 50 cells were scored. It was not compliant with GLP. Read-across to the registered substance is considered scientifically justified.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Deviations:
yes
Remarks:
50 cells/dose counted, guideline requires 200
GLP compliance:
not specified
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
mouse lymphoma L5178Y cells
Details on mammalian cell type (if applicable):
- Type and identity of media: Fischer's medium

- Properly maintained: yes
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced mouse liver S9
Test concentrations with justification for top dose:
See Table 1.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
medium only
Negative solvent / vehicle controls:
yes
Remarks:
ethanol (1% of final volume)
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
- MA (final conc. of 0.5 ul or 7.5 ul)
Untreated negative controls:
yes
Remarks:
medium only
Negative solvent / vehicle controls:
yes
Remarks:
ethanol (1% of final volume)
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
+ MA (final conc. of 2.5 * 10^-4 M and 1 * 10^-5 M)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)


DURATION

- Preincubation period: none

- Exposure duration: 4 hours

- Expression time (cells in growth medium): 24

- Fixation time (start of exposure up to fixation or harvest of cells): 28


SPINDLE INHIBITOR (cytogenetic assays): colcemid (concentration 2 * 10^-7 M)


STAIN (for cytogenetic assays): 5% Giemsa


NUMBER OF REPLICATIONS: 1


NUMBER OF CELLS EVALUATED: 50 per dose


DETERMINATION OF CYTOTOXICITY

- Method: toxicity was measured in a preliminary study, no further details reported.


OTHER EXAMINATIONS:

- Determination of polyploidy: yes

- Determination of endoreplication: no
Evaluation criteria:
Gaps were not counted as significant aberrations, open breaks were considered indicators of genetic damage, as were configurations resulting from the abnormal repair of breaks such as multiradials, rings and multicentrics. Pulverised cells and chromosomes were not included in the count since the number of aberrations is unknown. The estimated number of breaks involved in production of the different aberrations of cells observed, the frequency of cells with more than one aberration, and any evidence for increasing amount of damage with increasing dose, were taken into account in order to establish if the test substance is considered clastogenic.
Statistics:
Student t-test and blind scoring of aberrations.

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Remarks:
toxicity was measured but the results not reported.
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS

- Water solubility: measured, but not reported.

- Other confounding effects: no


RANGE-FINDING/SCREENING STUDIES: a screening test was conducted however the details were not reported.


COMPARISON WITH HISTORICAL CONTROL DATA: the negative control data falls within the an acceptable range of the historical control data (the positive control substance differed so no comparison was possible).


ADDITIONAL INFORMATION ON CYTOTOXICITY: toxicity was determined, however the results were not reported. In the previous study with the same substance no cytotoxicity was observed up to a concentration of 2.5 ul/ml.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 2a: Results of chromosome analysis, without metabolic activation (total of 50 cells).

 

Solvent control*

Control

0.156μl/ml

 0.313 μl/ml

 0.625 μl/ml

 1.25 μl/ml

 2.5 μl/ml

Positive control

Aberrations

 Cells with aberrations (%)

 6

 0

 2

 2

 0

 2

0

60

 Number and type of aberrations

 1tb, 1t, 1tr

 -

 1af

 1pu

 -

 1af

-

>158

 Cells with >1 aberration (%)

 0

 0

 0

 0

 0

 0

0

44

Where the solvent control is ethanol and the positive control is ethylmethanesulfonate(0.75μl/ml)

Abbreviations of aberration type: af = acentric fragment; pu+= pulverised chromosome; tr=triradial; t = translocation; tb = chromatid break

 

Table 2b: Results of chromosome analysis, with metabolic activation (total of 50 cells).

 

Solvent control*

Control

0.156 μl/ml

 0.313 μl/ml

 0.625 μl/ml

 1.25 μl/ml

 2.5 μl/ml

Positive control

Aberrations

 Cells with aberrations (%)

 0

 0

 2

 4

 2

 2

0

 68

 Number and type of aberrations

 -

 -

 1af

 1af, 1d

 1pu+

 1tr, 1r

-

>152

 Cells with >1 aberration (%)

 0

 0

 0

 0

 2

 2

0

56

Where the solvent control is ethanol and the positive control iscyclophosphamide (2.5 x 10 -4 M).

Abbreviations of aberration type: af = acentric fragment; d = dicentric chromosome; pu+ = pulverised chromosome; t r= triradial; r = ring

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test substance was tested in mouse lymphoma cells according to a protocol similar to OECD 473 (2000) and did not induce an elevated number of structural chromosomal aberrations. Therefore the test material can be considered negative under the conditions of the test.