Effects of cadmium on ultrastructure and steroidogenesis in cultured porcine ovarian granulosa cells

Cadmium is an environmental risk factor having various toxic effects both in animals and in humans. The aim of this study was to study its effects on the structure and function of porcine ovarian granulosa cells cultured in vitro. Ultrastructure of granulosa cells was studied after 48 h of culture with (0.2, 10 and 20 ng CdCl2/ml) of without cadmium using transmission electron microscopy (TEM). Quantification of progesterone and 17-beta-oestradiol was performed directly from aliquots of the media from control and treated cells by radioimmunoassay (RIA). After cadmium administration cell membranes were disintegrated. It was manifested by occurrence of vacuoles in the cytoplasm. The vacuoles contained fibrillar or membranous material. The Golgi complex rarely remained intact. Increased number of lysosomes was detected. With increasing cadmium concentrations the number of lipid droplets increased. In some cells the changes were less evident and dense mitochondria with distinct membranes were found. In other cell types the amount of mitochondrial matrix increased and that of membranes decreased. Some mitochondria fused with lysosomes. The endoplasmic reticulum rarely remained intact, and its dilation was well visible on transverse sections. Nuclei with distinct heterochromatin at the nuclear membrane were often observed. In these nuclei perinuclear cistern was dilated. Less frequently nuclei with condensed chromatin reminiscent of pyknosis were observed. Some nuclei had dispersed fine granular chromatin. In other cells changes were less evident, and comprised condensed chromatin in the central part of nuclei. These structural changes of granulosa cells exposed to cadmium were related to premature luteinization of these cells. In the evaluation of steroidogenesis we found that cadmium induced an increase in progesterone production, and a decrease in 17-beta-oestradiol production by ovarian granulosa cells; however, these differences were not significant. The results of our study elucidate some of the effects of cadmium on gonadal function, and should also serve to increase the level of awareness of its effects on human and animal health.