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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: well documented and NTP protocol conform

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1991
Report date:
1991

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
not specified
Type of assay:
mammalian cell gene mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Barium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]
EC Number:
225-935-3
EC Name:
Barium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]
Cas Number:
5160-02-1
Molecular formula:
C17H13ClN2O4S.1/2Ba
IUPAC Name:
barium bis{5-chloro-2-[(2-hydroxy-1-naphthyl)diazenyl]-4-methylbenzenesulfonate}
Details on test material:
All test chemicals were received as coded substances from the NTP Chemical Repository (Radian Corporation, Austin, TX). These were stored at 4°C or -20°C as directed. Just prior to each mutation experiment, an aliquot was placed into an appropriate solvent, and several dilutions were performed with the solvent.

Method

Target gene:
thymidine kinase (TK)
Species / strain
Species / strain / cell type:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver
Test concentrations with justification for top dose:
0, 1.25, 2.5, 5, 7.5 and 15 mug/ml trial 1 without metabolic activation
0, 1.25, 2.5, 5, 7.5, 10 and 15 mug/ml trial 2 without metabolic activation
0, 2, 3, 4, 5, 6 mug/ml trial 1 with metabolic activation
0, 2, 3, 4, 5, 6 and 8 mug/ml trial 2 with metabolic activation
Vehicle / solvent:
DMSO
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without metabolic activation
Positive controls:
yes
Positive control substance:
3-methylcholanthrene
Remarks:
with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 4h
- Expression: 2d, viable cell densities were determined by hemacytometer each day using trypan blue dye exclusion.

NUMBER OF REPLICATIONS: test substance and positive control tested in triplicate, 5 solvent controls

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
A chemical is evaluated for a test condition (-S9, +S9, +NS9) only if two or more acceptable experiments are available

1. Positive (+)
I. Replicate experiments are positive
II. Questionable experiments are reproducible

2. Questionable (?)
I. Replicate experiments yield results that just meet or just fail the tests for significance
II. Replicate experiments are evaluated as positive or not positive (= or -) and no reason exists to subordinate either evaluation

3. Negative (-1)
Replicate experiments are not positive (= or -)

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
Preliminary studies of test chemical solubility and cytotoxicity were conducted prior to performing the first mutation experiment. The solubility of the test chemical in treatment medium was examined carefully in clear tubes and without cells; centrifugation and microscopic examination were sometimes used to detect suspensions of fine particles. Changes in pH were noted by the color of the phenol red indicator in the medium, but, unless otherwise noted, no pH adjustments were made. Test chemical toxicity to 24-hr cell suspension growth was determined for 4-hr treatments with a range of doses up to a maximum of 5,000 pg/ml.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

D & C red 9 was not toxic or mutagenic to L5178Y cells, with or without the addition of S9 mix. No significant increases in the MF were observed. The solubility limit in Fischer’s medium was 7.5 microg/ml, but concentrations up to 15 microg/ml (without S9) were tested without any toxic effects.