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Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Jan 29 - Feb 28, 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was performed in compliance with the Good Laboratory Practice (GLP) regulations (revised in 1997, ENV/MC/CHEM(98)17). The method followed that described in the OECD Guidelines for Testing of Chemicals (Adopted: 4 April 1984) No 471 "Bacterial Reverse Mutation Test".

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Principles of method if other than guideline:
None
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test material identity and characteristics
Synonym: CC-5-V
Batch: E96844401
Appearance: off auburn-dyed, viscous liquid
Released until: July 30, 1998
Purity (HPLC): 99.6 %
Storage conditions:tightly closed, in darkness at room temperature

Method

Target gene:
HIS operon (S. thyphimurium)
TRY operon (E. coli)
Species / strainopen allclose all
Species / strain:
S. typhimurium TA 1535
Details on mammalian cell lines (if applicable):
his G 46, uvrB, rfa
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
rat liver homogenate (S9 mix) with standard co-factors with metabolic activation (Aroclor)
Species / strain:
S. typhimurium TA 1537
Details on mammalian cell lines (if applicable):
his C 3076, uvrB, rfa
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 98
Details on mammalian cell lines (if applicable):
his D 3052, uvrB, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 100
Details on mammalian cell lines (if applicable):
his G 46, uvrB, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 102
Details on mammalian cell lines (if applicable):
his G 428, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
E. coli WP2
Details on mammalian cell lines (if applicable):
his C 3076, uvrB, rfa
Additional strain characteristics:
other: mutations in the tryptophan operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Test concentrations with justification for top dose:
The test material concentrations were used selected according to the EC and OECD guidelines for this test system and the requirements of the Labor Ministry of Japan:
1. Series: 5, 15.8, 50, 158, 500, 1580, and 5000 µg/plate
2. Series: 5, 15.8, 50, 158, and 500 µg/plate
Vehicle:
Acetone
Controlsopen allclose all
Negative controls:
no
Solvent controls:
yes
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Positive control substance:
other: Aminoacridine
Details on test system and conditions:
The assessment of test material-induced effects is dependent on the number of spontaneous revertants of each
bacterial strain (solvent controls) and the in-crease in the number of revertants at the test material
concentration which shows the highest number of colonies.
The following criteria, based upon the historical controls of the laboratory and statistical considerations,
are established:

-----------------------------------------------------------------------------------------
Mean Number of Colonies Maximal Mean Number of Colonies over the Actual
(Solvent Control) Solvent Control
(Test Material)
-----------------------------------------------------------------------------------------

<=10 <=9 >=30
<=30 <=19 >=40
<=80 <=29 >=80
<=200 <=49 >=120
<=500 <=79 >=200
Assessment No increase Clear increase

-----------------------------------------------------------------------------------------

All further results, ranging between "no" and "clear", are assessed as "weak in-creases".
Interpretations:
A test material is defined as non-mutagenic in this assay if "no" or "weak increases" occur in the first and second series of the main experiment.
("Weak increases" randomly occur due to experimental variation.)

A test material is defined as mutagenic in this assay if:

- a dose-related (over at least two test material concentrations) increase in the number of revertants is induced, the maximal effect is a "clear increase", and the effects are reproduced at similar concentration levels in the same test system;

- "clear increases" occur at least at one test material concentration, higher concentrations show strong precipitation or cytotoxicity, and the effects are reproduced at the same concentration level in the same test system.

In all further cases, a third test series with the bacterial strain in question should be performed.
If the criteria for a positive test result are not fulfilled in at least two out of the three series, the test material is defined as being non-mutagenic in this test system.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
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 with and without metabolic activation

With and without addition of S9 mix as the external metabolizing system, the test item was not mutagenic under
the experimental conditions described.
Executive summary:

Purpose

The purpose of this assay was to provide information on possible health hazards for the test material and serve as a rational basis for risk assessment to the genotoxic potential of the test item in man.

Study Design

The investigations for the mutagenic potential of CC-5 -V were performed using Salmonella typhimurium tester strains TA 98, TA 100, TA 102, TA 1535 and TA 1537, and Escherichia coil WP2 uvrA. The plate incorporation test with and without addition of liver S9 mix from Aroclor 1254-pretreated rats was used. Two independent experimental series were performed.

Results

CC-5 -V was dissolved in acetone and tested at concentrations ranging from 5 to 5000 µg/plate. Precipitation of the test material on the agar plates occurred at concentrations 500 µg/plate. Toxicity to the bacteria was not observed.

Daunomycin, N-ethyl-N'-nitro-N-nitrosoguanidine, 9-aminoacridine and cumene hydroperoxide served as strain specific positive control test materials in the absence of S9 mix. 2-Aminoanthracene and benzo[a]pyrene were used for testing the bacteria and the activity of the S9 mix. Each treatment with the test materials used as positive controls led to a clear increase in revertant colonies, thus, showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used.

In both series of experiments, each performed with and without the addition of rat liver S9 mix as the external metabolizing system, CC-5 -V showed no increase in the number of revertants of any bacterial strain. According to the criteria for negative and positive results predetermined in the Study Protocol (cf also "Criteria for negative and positive results"), CC-5 -V was not mutagenic under the described experimental conditions.

Conclusion

With and without addition of S9 mix as the external metabolizing system, CC-5 -V was not mutagenic under the experimental conditions described.