Comparative cytotoxicity of exogenous cadmium-metallothionein and cadmium ion in cultured vascular endothelial cells

Using cultured vascular endothelial cells derived from bovine aorta, the cytotoxicity of cadmium-metallothionein (Cd-MT) was compared to that of cadmium chloride. The analytical procedures are described. Results indicated that Cd ions were strongly cytotoxic, while Cd-MT did not show such a cytotoxic effect, suggesting that metallothionein plays a protective role against Cd toxicity. The accumulation of intracellular Cd in endothelial cells was significantly less in the Cd-MT-exposed groups compared to the CdCl sub(2)-exposed groups. This indicates that protection by extracellular metallothionein against Cd toxicity may be primarily due to a reduction in Cd uptake.