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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:
weight of evidence
Study period:
1984
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
documentation insufficient for assessment
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Primary mutagenicity screening of food additives currently used in Japan
Author:
M. Ishidate Jr, T. Sofuni, K. Yoshikawa, M. Hayashi, T. Nohmi, M. Sawada and A. Matsuoka
Year:
1984
Bibliographic source:
Fd Chem. Toxic. Vol. 22, No. 8, pp. 623-636

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: method of Ishidate & Odashima (1977)
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
GLP compliance:
not specified
Type of assay:
other: in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain:
other: Chinese Hamster Lung Fibroblast (CHL)
Details on mammalian cell lines (if applicable):
The cell line was originally established from the lung of a newborn female at the Cancer Research Institute, Tokyo (Koyama, Utakoji & Ono, 1970), and was maintained by 4-day passages in Minimum Essential Medium (MEM; GIBCO) supplemented by 10% calf serum.
The modal chromosome number is 25 and the doubling time was approximately 15 hr.
Additional strain characteristics:
not specified
Metabolic activation:
without
Test concentrations with justification for top dose:
3 different concentrations tested but not specified in the publication.
The maximum dose of each sample was selected by a preliminary test in which the dose needed for 50% cell-growth inhibition was estimated using a cell densitometer (Monocellater, Olympus Co., Ltd).
Previous studies indicated that the osmotic pressure of the medium generally rose with sample concentrations of more than 10 mM, so that the maximum dose for some samples was limited to around this level, at which cytotoxic effects were not necessarily ubserved.
Vehicle:
Ethanol
No justification given
Controls
Negative controls:
yes
Remarks:
untreated cultures
Solvent controls:
yes
Remarks:
same treatment but exposed only to DMSO
True negative controls:
not specified
Positive controls:
not specified
Positive control substance:
not specified
Details on test system and conditions:
The cells were exposed at three different doses for 24 and 48 hr. In the present study, no metabolic activation systems were applied.

Chromosome preparations were made as follows:
Colcemid (final concn 0.2 µg/ml) was added to the culture 2 hr before cell harvesting. The cells were then trypsinized and suspended in a hypotonic KCI solution (0.075 M) for 13 min at room temperature. After centrifugation the cells were fixed with acetic acid-methanol (1:3, vJv) and spread on clean glass slides. After air-drying, the slides were stained with Giemsa solution (1.5%, at pH 6.8; E. Merck) for 12-15 min. A hundred well-spread metaphases were observed under the microscope (x 600 with a no-cover objective lens). The incidence of polyploid cells as well as of cells with structural chromosomal aberrations such as chromatid or chromosome gaps, breaks, exchanges, ring formations, fragmentations and others, was recorded on each culture plate.

Untreated cells and solvent-treated cells served as negative controls, in which the incidence of aberrations was usually less than 3.0%.
Evaluation criteria:
The results were considered to be negative if the incidence was less than 4.9%, equivocal if it was between 5.0 and 9.9%, and positive if it was more than 10.0%.
Statistics:
no documentation available

Results and discussion

Test results
Species / strain:
other: Chinese Hamster Lung Fibroblast (CHL)
Metabolic activation:
without
Genotoxicity:
negative
Remarks:
at the highest non cytotoxic dose tested (0.2 mg/ml)
Cytotoxicity:
no
Vehicle controls valid:
not specified
Negative controls valid:
yes
Positive controls valid:
not specified
Additional information on results:
Percentage of structure aberrations after 48 hours: 4%
no further details available

Any other information on results incl. tables

no detailed table given

Applicant's summary and conclusion

Conclusions:
Interpretation of results: negative

The test material is not clastogenic under the used test conditions