Abstract
The effects of Toc-suc or B_2 on the cytotoxicity of sodium chromate or UV light were examined by colony forming assay using Chinese hamster V-79 cells. Pretreatment with Toc-suc for 24h prior to exposure resulted in a decrease in the cytotoxicity of both sodium chromate and UV light. In contrast, similar pretreatment with B_2 did not influence the cytotoxicity of UV light. In the case of chromate, however, pretreatment with B_2 resulted in a decrease of cytotoxicity after exposure to the usual lethal does (15μM) of chromate, but did not affect the cytotoxicity at sublethal doses (5〜10μM) of this metal. Under chromate-exposure conditions, neither pretreatment with Toc-suc nor B_2 had any effect on cellular uptake of chromate. These results suggest that the induction of cytotoxicity by chromate and UV light may be associated with their generation of free radicals, and indicate that the effect of B_2 against cytoxicity may be due to a different mechanism than that for Toc-suc.
