The toxicity of sixteen metallic compounds in Chinese hamster ovary cells

Abstract

The toxicity of 16 metal salts to Chinese hamster ovary (CHO) cells was determined by measuring the cloning efficiency (CE) of CHO cells after exposure to the metals. CHO cells differed by a factor of 10 5 to 10 6 in their toxic response to these metal salts. While Cd(II) was the most toxic ion, Mg(II) exhibited the least toxicity based on either CE50 (concentration required to reduce the CE to 50%) or D 0 (concentration increment which reduced the CE by 63%). On the basis of CE50, the toxicity ranking was Ag > Tl for monovalent metals, Cd > Zn > Hg > Co > Cu > Mn > Ni > Be > Pd > Sr > Mg for divalent metals, and In > Rh > Y for trivalent metals. A similar ranking was found for D 0. For the 11 divalent metals, correlations of CE50 and D 0 in the CHO cell assay and the Pearson-Mawby softness parameter for metals (δ p) were reasonably strong. A good correlation exists between the results of this study on the toxic response in CHO cells and published data on toxicity in mice and Drosophila. It appears that the CHO cell cloning assay may be useful in preliminary screening of metallic compounds as an indicator of their predicted toxicity in higher organisms.