Light and electron microscopic investigation of the rat placenta after cadmium administration during pregnancy.

The morphology of the rat placenta was studied after exposure to cadmium chloride during pregnancy, using optimal fixation conditions. In contrast to previous observations, no differences were observed after cadmium administration in relative volume densities of trophoblastic tissue, maternal lacunae, fetal capillaries and connective tissue, nor in trophoblastic thickness or other morphometric features. At the ultrastructural level, the amount of glycogen in trophoblast layer II was elevated in cadmium exposed rats, but other electron microscopic features (amount and localization of lipid, degenerative vesicles, thickness and general appearance of the trophoblastic and endothelial layers and thickening or multiplication of the basal lamina) were not changed. Results obtained from the present experiments do not support the suggestion that cadmium is responsible for structural changes in the placentae of human smokers.