Bismuth Induces Metallothionein but Does Not Protect Against Cadmium Cytotoxicity in Cultured Vascular Endothelial Cells

Abstract

Cadmium has been shown to be an inducer of cardiovascular lesions such as atherosclerosis and hypertension. The relationship between cadmium exposure and vascular diseases was shown by epidemiological data. We found that cadmium destroys the monolayer of cultured vascular endothelial cells. This suggested that damage of vascular endothelial cells may be an important event of cadmium-induced vascular disorders. Metallothionein induction is postulated to be in general the most important mechanism for protection against cadmium toxicity. However, zinc protects vascular endothelial cells from cadmium cytotoxicity without metallothionein induction; zinc was not an effective inducer of the protein. Recently, we found that bismuth strongly induces metallothionein selectively in vascular endothelial cells. Although zinc protection against cadmium cytotoxicity in vascular endothelial cells mainly resulted from a decrease in the accumulation of intracellular cadmium, it was likely that bismuth reduces the cytotoxicity of cadmium by the metallothionein-dependent mechanism in the cells. In the present study, the effect of bismuth on the cytotoxicity of cadmium in cultured vascular endothelial cells was investigated. Bismuth alone induces metallothionein but does not protect against cadmium cytotoxicity in the cells. 14 refs., 1 tab.