Abstract
Effects of osmotic acclimation on apoptotic cell death of a fish cell line (Epithelioma Papulosum Cyprini, EPC) were investigated. The culture acclimated to moderate hypertonic medium (400mOsm/kg) showed less DNA fragmentation, the feature of apoptosis, with the exposure to severe hypertonic media (500 and 600mOsm/kg), than the culture acclimated to isotonic medium (300mOsm/kg). In contrast, the culture acclimated to moderate hypotonic medium (200mOsm/kg) exhibited more remarkable DNA fragmentation when exposed to the hypertonic media. The suppression of apoptosis by hypertonic acclimation could be explained by the shift of the threshold of osmotic pressure to trigger apoptosis. Because DNA fragmentation with the exposure to hypotonic medium was not observed in all the cultures acclimated to 200, 300, or 400mOsm/kg medium, EPC has an intrinsic viability against hypotonic environment.
