Peculiarities of RBCs resistance to acid hemolysis in hibernating mammals

The binding of acids and alkalis, formed in tissues by metabolism, along with oxygen and CO2 transport are recognise as the principal functions of red blood cells (RBCs). Decreases in internal environment pH may result in activation of potential endogenous cytotoxic metabolites, OH˙ and oxidant formation and, as a consequence, result in oxidative damage of cell membrane leading to hemolysis. The characteristics of acid hemolysis in hibernating mammals have been determined in this study. Parameters of HCl-hemolysis, such as the average time for RBC hemolysis and the population distribution of the response, have been investigated. Measurements were performed within 40–5 °C temperature range. The resistance of hibernator RBCs to increased acidity, determined according to the acid hemolysis parameters, was found to reflect whether the animal was in the summer active period or in hibernation, with differences also apparent at different points with the hibernation season itself. It was demonstrated that hemolysis parameters of naturally cold-tolerant organisms are altered by decreases in temperature. We discuss a role of cytoskeletal–membrane interactions as a fast-acting switch of the structural and functional state of hibernator RBCs as an adaptation mechanism to acidosis arising from hypothermia and hypermetabolism.