Little is known on the protective effects of L-proline on hen erythrocytes. The aim of the study was to determine the protective effects of this amino acid at concentrations of 50 μg/mL, 100 μg/mL, 200 μg/mL in hen erythrocytes subjected to temperatures 41 °C, 43 °C and 45 °C for 1 h and 4 h. The following cellular parameters were determined: viability, morphological alterations, caspase 3/7 activity, heat shock protein HSP70 1A activity and glutathione level. The results showed that exposure to 43 °C and 45 °C resulted in a decrease of viability and increased morphological alterations of the non-treated erythrocytes. Caspase 3/7 activity was increased only at 45 °C, however HSP70 1A activity and glutathione level were increased in the temperature-dependent manner. On the other hand, erythrocytes additionally exposed to L-proline showed alterations of the parameters when compared to the non-treated cells. L-proline at 50 μg/mL and 100 μg/mL increased caspase 3/7 activity at both 41 °C and 43 °C, however it was less augmented at all the concentrations at 45 °C. Glutathione level was decreased in heat-stressed (at 43 °C and 45 °C) hen erythrocytes treated with L-proline (at 50 μg/mL and 100 μg/mL) but it was increased at 200 μg/mL. HSP70 1A activity was augmented in a concentration- and temperature-dependent manner. The results indicate that proapoptotic or antiapoptotic effects of L-proline depend on its concentration and temperature of heat stress and thermoprotective effects induced by the amino acid on some parameters in hen erythrocytes may be a result of stimulation of antioxidative defense and stimulation of HSP70 1A activity.
Keywords: Apoptosis; Glutathione; HSP70; Heat stress; Hen erythrocytes; L-proline.
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