THE EFFECTS OF CADMIUM EXPOSURE ON THE CYTOLOGY AND FUNCTION OF PRIMARY CULTURES FROM RAINBOW-TROUT

Cultured epidermal cells from explants of skin of rainbow trout were u sed to study the cytological and functional changes following subletha l exposure to cadmium stress. The aim was to develop diagnostic marker s for ecotoxicology. Cultures were exposed to the pollutant for 48 h. Cell structural and cytological changes were established by light and electron microscopy, Metabolic alterations were detected by immunohist ochemistry. The relation between the initiation of cellular alteration s and cadmium concentrations was compared in cultures exposed in comme rcially-available serum-free and serum-containing medium, The expressi on of stress proteins (metallothionein and heat shock protein) was als o studied, Rainbow trout epithelial cells exposed to cadmium showed ty pical morphological changes indicative of cell death by apoptosis. Sub lethal exposure also resulted in cellular metabolic disturbances with increased deposits of glycogen. Increased melanization was also observ ed. These changes appeared at lower concentrations of cadmium when cel ls were exposed in serum-free media than in serum-containing media. Ca dmium induced the expression of heat shock proteins but not of metallo thioneins. The results broadly confirm in vivo findings for cadmium to xicity and suggest that this in vitro technique may have applications in aquatic toxicology. (C) 1998 John Wiley & Sons, Ltd.