Effect of cadmium on the monolayer maintenance of vascular endothelial cells in culture.

We investigated the effect of cadmium on the maintenance of the monolayer of vascular endothelial cells to clarify a possible involvement of endothelium injury in cadmium-induced vascular disorders. Endothelial cells from bovine aorta were cultured with cadmium chloride (0.5, 1.0, 2.0 or 5.0 microM) for 24 or 72 h. A histological observation revealed that a de-endothelialized space was formed in the monolayer by cadmium treatment; the number of endothelial cells was significantly decreased by the metal. Cadmium significantly decreased the number of growing endothelial cells with a significant decrease in the [3H]thymidine incorporation, suggesting that cadmium inhibited the cell proliferation. On the other hand, cadmium significantly increased the detachment of [3H]thymidine-labeled endothelial cells from the monolayer with a parallel increase in the lactate dehydrogenase activity in the medium. From these results, it was suggested that cadmium impairs the endothelial cell monolayer; the de-endothelialized space was formed by both an increase in the cell detachment by cadmium cytotoxicity and a retardation of the repair of the space which was due to an inhibition of the cell proliferation caused by the metal.