Sister Chromatid Exchange Induced by Promutagens/Carcinogens in Chinese Hamster Cells Cultured in Diffusion Chambers in Mice 1

Summary

A system for in vivo analysis of sister chromatid exchange (SCE) was described. It involved culturing Chinese hamster V-79 cells in diffusion chambers (DC) in mice. Treatment of the hosts with repeated injections of 5-bromodeoxyuridine permitted the demonstration of differentially stained metaphases in the V-79 target cells after using the fluorescence plus Giemsa technique. Thus, it was possible to determine the number of SCE's under in vivo conditions. Induction of SCE in V-79 cells in vivo were studied following treatment with seven known promutagens/carcinogens: Cyclophosphamide, 1-(pyridyl-3)-3,3-dimethyltriazene, dimethylnitrosamine, diethylnitrosamine, benzo(α)-pyrene, 7,12-dimethylbenz(α)anthracene, 3-methylcholanthrene and three nonmutagens/noncarcinogens: perylene, pyrene, and anthracene. With the exception of DEN, all the promutagens/carcinogens caused a significant increase in the frequency of SCE. DEN was effective at the highest dose studied only after pretreatment with Aroclor 1254, a known mixed-function oxidase inducer. SCE analyses of the nonmutagens/noncarcinogens resulted in no increase of SCE frequency as compared to the controls. These results indicate that SCE analyses in V-79 cells in DC in mice may provide a convenient, sensitive, and economical host-mediated assay system for detecting certain classes of environmental mutagens or carcinogens.