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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
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Qualifier:
according to guideline
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
GLP compliance:
yes
Type of assay:
other: chromosomal aberrations

Test material

Constituent 1
Test material form:
liquid
Details on test material:
MITI No. 5-3720, CAS No. 2057-49-0, molecular weight 197.28, yellow liquid, solubility in water: 319 mg/L (est.) (SRC)
Specific details on test material used for the study:
Sponsor's identification 4-(3-phenylpropyl)pyridine
CAS No: 2057-49-0
Description: Yellow liquid
Purity: 98.31%

Method

Target gene:
chromosomes
Species / strain
Species / strain / cell type:
Chinese hamster lung fibroblasts (V79)
Details on mammalian cell type (if applicable):
CHL/IU cells derived from Chinese hamster, obtained from Research · Resource Bank (JCRB) (February 1988, at passage: 4th passage, now 12th) were used in the test within 10 years of thawing succession age.
Cytokinesis block (if used):
colcemid
Metabolic activation:
with and without
Metabolic activation system:
S9 fraction from livers of rats induced with phenobarbital and 5,6-benzoflavone
Test concentrations with justification for top dose:
A preliminary toxicity test was conducted based on cell proliferation rates. The proliferation inhibitory action of the test substance on CHL/IU cells was determined by measuring the proliferation of each group using a monolayer culture cell densitometer (Monocellater ™ , Olympus Optical Co., Ltd.), and the solvent control group as baseline.
Vehicle / solvent:
acetone
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
mitomycin C
Details on test system and experimental conditions:
DURATION
-Exposure duration:
a) Continuous treatment: 24 hrs, 48 hrs
b) Short-term treatment: 6 hrs; 18 hrs for recovery
-Fixation time (start of exposure up to fixation or harvest of cells):
a) Continuous treatment: 24 hrs, 48 hrs
b) Short-term treatment: 24 hrs
Vehicle: DMSO
SPINDLE INHIBITOR: Colcemid
STAIN: Giemsa stain
NUMBER OF CELLS EVALUATED:
Stractural aberrations: 200 cells/group
Polyploidy: 800 cells/group
DETERMINATION OF CYTOTOXICITY:
-Method: relative total growth
Rationale for test conditions:
guideline
Evaluation criteria:
Criteria for a positive call: a statistically significant increase in the frequency of cells with chromosomal aberrations in the treated group compared with that of the solvent control group, and a statistically significant difference in the dose trend test. An inconclusive result will be designated when there is a significant increase in the frequency of cells with aberrations without a postive dose response trend test.
The test will be considered negative when there is no significant difference in frequency of cells with chromosomal aberrations.
The test is inconclusive when the number of cells observed has fewer than 100 structural aberrations, and less than 400 polyploidy due to cytotoxicity.
Statistics:
Fisher's direct probability method is used to distinguish between the solvent background chromosomal aberration levels and those of the test substance- treated group, with a significance level of p <0.05. In addition, when significant differences were found by Fisher's exact stochastic method, the Cochran-Armitage's trend test is applied (p <0.05) to test for significance of the dose dependency.

Results and discussion

Test results
Key result
Species / strain:
Chinese hamster lung fibroblasts (V79)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
In the dose-range finding studies, concentrations were up to 1970 μg /mL, with precipitate seen above 246 μg /mL in the continuous assay and the short term assay with S9. In the short term assay without S9, precipitate was seen at and above 492.5 µg/ml. In all assays the test material showed evidence of cell toxicity.

Any other information on results incl. tables

In the main assay, the cell count data show that an approximate 50% growth inhibition was achieved at 60 µg/ml in the absence of S9, whilst in the presence of S9 21% growth inhibition was achieved at 80 µg/ml. No precipitate of the test material was observed at the end of the exposure period in either the absence or presence of S9. The test material did not induce any statistically significant increases in the frequency of cells with structural chromosome aberrations or polyploidy either in the presence or absence of metabolic activation. All controls behaved within historical ranges.

Applicant's summary and conclusion

Conclusions:
A guideline OECD 473-compliant chromosomal aberration test was undertaken with the test material in DMSO, with and without rat liver S9 fraction, with valid positive controls. Cytotoxicity was seen at the higher doses in a preliminary dose-range finding study. There were no increase in the number of chromosome aberrations or polyploidy observed. The test substance does not induce chromosomal aberration in CHL/IU cells under the conditions of this study.