Comparison of cytotoxic effects of chemicals in four different cell types.

Cytotoxic effects were compared using a colony-formation assay in three established cell lines (Balb 3T3, mouse whole embryo, ARLJ301-3, rat liver and FRSK, rat keratinocytes) and one primary cell culture (RC-1, rabbit cornea) with the Draize eye irritancy score in vivo. The cells were treated with 52 chemicals on the day after plating, then cultured for 7 or 8 days. The 50% inhibition dose (ID(50)) for each chemical was calculated based on the colony number. With a few exceptions, the cytotoxicities of the chemicals were in the following order in all four cells: cationic detergents anionic detergents non-ionic detergents glycol or oil. These results were almost the same as the data in vivo. The correlation coefficients of the ID(50) to the Draize score of 20 in vivo were 0.57 (Balb 3T3), 0.61 (ARLJ301-3), 0.71 (FRSK) and 0.65 (RC-1). Balb 3T3 and ARLJ301-3 cells were slightly more sensitive to chemicals than FRSK and RC-1 cells. These results suggest that the colony-formation assay using established cell lines is an attractive method for the screening of chemicals in that large differences among cell types in their response to direct-acting chemicals, were not observed.