Survival and Metabolic Function of Freshly Isolated Rat Hepatocytes Exposed First to a Heat Shock and Then to an Oxidative Stress

The formation of heat shock proteins (hsp) leading to thermotolerance has been extensively reported in many cell types. In freshly isolated rat hepatocytes, hsp were synthesized after 60 minutes of incubation at 42°C. Cell survival was not modified by such a treatment, but protein synthesis, secretion of triglycerides as lipoproteins, and the maintenance of both ATP and glycogen levels were significantly impaired. When exposed to an oxidative stress, heat-shocked hepatocytes were not more resistant than cells always kept at 37°C. Conversely, the addition of tert-butyl hydroperoxide (tBOOH) resulted, in general, in an increased lactate dehydrogenase leakage. The metabolism of tBOOH, as estimated by the reduced glutathione (GSH) content and GSH peroxidase activity, was similar in both control and heat-shocked hepatocytes. Despite the synthesis of hsp in rat hepatocytes, the lack of resistance to a subsequent oxidant injury may be due to the metabolic impairment caused by the heat shock.