HSP expression in human leukocytes is modulated by endurance exercise

Purpose: Temperature increase, oxidative stress, and inflammatory reactions after endurance exercise were expected to stimulate the synthesis of heat shock proteins (HSP) in peripheral blood leukocytes. Furthermore, it was of interest whether regular endurance training influences HSP expression. Methods: The expression of HSP27, HSP60, HSP70, constitutive HSC70, and HSP90 in the cytoplasma and surface of lymphocytes, monocytes, and granulocytes of 12 trained athletes was analyzed by flow cytometry before and after (0, 3, and 24 h) a half marathon. Twelve untrained persons at rest were included as control. Results: After the race, there was a significantly greater percentage of leukocytes expressing cytoplasmic HSP27, HSP60, and HSP70 (P < 0.01), whereas HSC70 and HSP90 remained unchanged. The fluorescence intensity increased significantly in monocytes for HSP27 (0 and 3 h) and HSP70 (0, 3, and 24 h) and in granulocytes, only 24 h postexercise for HSP70. The percent values of trained athletes at rest were significantly lower compared with untrained persons (P < 0,01). Conclusions: Strenuous exercise increased HSP expression in blood immediately after the run, indicating a protective function of HSP in leukocytes of athletes to maintain function after heavy exercise. The downregulation of HSP-positive cells in trained athletes at rest seems to be a result of adaptation mechanisms to regular endurance training.