STUDIES ON CYTOTOXIC AND GENOTOXIC EFFECTS OF CADMIUM NITRATE AND LEAD NITRATE IN CHINESE-HAMSTER OVARY CELLS

Cadmium nitrate decreased the viability of Chinese hamster ovary (CHO) cells in a concentration-dependent manner; 50% inhibition (IC50) was achieved at 0.015 mM. In contrast, lead nitrate appeared to be less toxic. Neither cadmium nitrate nor lead nitrate significantly increased frequencies of binucleated CHO cells with micronuclei (MN). However, both cadmium nitrate and lead nitrate could augment sister chromatid exchanges (SCEs). Cadmium nitrate induced SCEs with a potency approximately equal to that of mitomycin C and more than 10 times higher than lead nitrate. Cadmium nitrate also increased chromosome aberrations (CAs), which included breaks, acentrics interchanges, and dicentrics of chromosomes. In addition, cadmium nitrate induced a decrease in the mitotic index (MI), but lead nitrate increased it. In summary, it appears that both of these two heavy metal salts have cytogenetic toxicities with different degrees of effects on the cytotoxicity, MN, CAs, and SCEs in CHO cells. However, SCE was the most sensitive endpoint for indicating mutagenetic effects of cadmium and lead in the present study. (C) 1994 Wiley-Liss, Inc.