Expression of Exercise-Induced HSP70 in Long-Distance Runner??s Leukocytes

Abstract

0594 Heat shock proteins (HSP) are synthesized by cells of all organism resistance to internal and external cellular stresses including physical stress, metabolic stress, and disease. Exercise is a sufficient stimulus to induce and enhance the synthesis of HSP70, prolonged endurance exercise also causes an inflammatory reaction. Exercise induced a transient elevation in circulating leukocytes, driven largely by a granulocytosis but also influenced by an increase monocytes and lymphocytes. A few studies have examined the expression of HSP70 in human leukocytes, but there is no literature that compare the expression of HSP70 in trained athletes and that in untrained subjects under moderate-to-heavy exercise. PURPOSE: Present study was designed to investigate the expression of HSP70 in human peripheral blood leukocytes after acute moderate intensity exercise in trained runner and untrained subjects. METHODS: Ten male long-distance runners (TR, n = 10, 21.3 ± 1.1 yrs) and untrained control subjects (UT, n = 10, 22.4 ± 1.5 yrs) participated in this study. Subjects ran on a treadmill for 1 hr at 70% of heart rate reserve (HRR). Blood were taken immediately before and immediately after exercise, and at 30 minutes after exercise. Simultaneously, body weight and oral temperature were measured. HSP protein and mRNA were evaluated by immunoblotting and RT-PCR. RESULTS: Baseline HSP70 protein levels in TR was significantly lower than that in UT (P <.01), otherwise, basal HSP70 mRNA level in TR significantly higher than that in UT (P <.001). Although HSP70 transcription highly increased in TR versus UT during exercise and recovery period, but HSP70 synthesis did not matched as much as mRNA expression in TR. On the contrary, higher HSP70 protein levels maintained in UT, but rate of stimulate-induced mRNA expression seemed to be weak and disappeared quickly. UT showed increases in leukocytes (P <.01) and neutrophils (P <.01) and lymphocytes (P <.01) after exercise and recovery period versus TR (P <.01, P <.05, P <.05, respectively). CONCLUSION: We conclude that 1hr treadmill running at 70% HRR intensity (moderate-to-heavy) is a sufficient stimulus of leukocytosis, neutrocytosis, lymphocytosis, and HSP70 expression in leukocytes. Higher transcription and lower translation of HSP70 in TR under moderate intensity exercise, as observed in our study, remains to be investigated further.