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.