Cadmium toxicity to the cornea of pregnant rats: Electron microscopy and x‐ray microanalysis

Cadmium toxicity to the cornea of pregnant rats was studied using the electron microscope and x‐ray microanalyzer. In in‐vivo experiments, severe corneal edema occurred in pregnant dams that received intraperitoneal injections of cadmium sulphate for 4 days during gestation, but not in nonpregnant rats. Prominent swelling of mitochondria and the occurrence of intra‐ and inter‐cellular vacuoles in the corneal endothelium were observed only in pregnant dams. In in‐vitro experiments, electron‐dense deposits consiting of cadmium‐oxine complexes were preferentially found in swollen mitochondria of the endothelial cells. Cadmium peaks were obtained from these deposits with x‐ray microanalysis. These data suggest that the corneal edema observed after administration of cadmium may imply the disturbance of pump function and barrier function of the corneal endothelium due to the primary toxic effects of this metal on mitochondria.