SFTG international collaborative study on in vitro micronucleus test V. Using L5178Y cells

Area of Science:

• Genotoxicity testing
• In vitro assays
• Mammalian cell assays

Background:

• The in vitro micronucleus assay is a key tool for assessing genotoxicity.
• Standardization of protocols for mammalian cell assays is crucial for reliable results.
• Mouse lymphoma L5178Y cells are widely used in genotoxicity testing.

Purpose of the Study:

• To evaluate the suitability of mouse lymphoma L5178Y cells for the in vitro micronucleus assay.
• To compare different testing protocols to determine a standard method.
• To assess the genotoxic potential of various test chemicals.

Main Methods:

• An international collaborative study involving multiple laboratories.
• Evaluation of chemicals including bleomycin, 5-fluorouracil, colchicine, and griseofulvin.
• Application of varied protocols: short/long exposures, recovery times, and cytochalasin B presence/absence.

Main Results:

• Bleomycin induced a concentration-dependent increase in micronucleated cells.
• 5-fluorouracil, colchicine, and griseofulvin yielded equivocal results, with cytotoxicity impacting aneuploidy assessment.
• Both short and long treatment times were necessary for detecting genotoxicity; recovery periods aided in identifying compounds affecting cell proliferation.

Conclusions:

• Mouse lymphoma L5178Y cells are confirmed as suitable for the in vitro micronucleus assay.
• Protocol variations, including exposure duration and recovery time, influence results.
• Standardization efforts are needed to optimize the assay for routine genotoxicity testing.