Cellular responses in primary epidermal cultures from rainbow trout exposed to zinc chloride

In this study, we examined the effects of zinc chloride (ZnCl₂) (0-200 mg/L) on primary epidermal cultures from Oncorhynchus mykiss. Increases in the rate and amount of mucus released were detected post-exposure, as was a dose-dependent increase in the synthesis of acidic glycoproteins. The cytotoxicity of ZnCl₂ to the cultures was significantly increased (P ≤ 0.05) when exposures were conducted in serum-free medium as opposed to medium containing serum. Significant increases in the levels of apoptosis and necrosis were observed with increasing exposure concentration, but these were seen to decrease over time. The in vitro cytological and pathological changes observed in this study were found to be in accordance with previously published in vivo studies on the effects of heavy metals on the integument. This model system may help to further elucidate the effects of ecotoxicants on the external innate immune system of fish.