Transcriptional and translational regulation of heat shock proteins in leukocytes of endurance runners

Heat shock proteins (HSP) represent cell-protective and antioxidant systems that may be induced by reactive oxygen species, cytokines, and hyperthermi a. In the present study, we evaluated the influence of heavy endurance exer cise and training on HSP27 and HSP70 in peripheral leukocytes of 12 athlete s (before and at 0, 3, and 24 h after a half-marathon) and 12 untrained con trols on protein and mRNA levels by flow cytometry and RT/PCR, respectively . HSP transcripts increased significantly immediately after acute exertion accompanied by elevated levels of corresponding proteins. HSP protein expre ssion remained high until 24 h postexercise. Significant increases of plasm a interleukin-8, myeloperoxidase, and creatine kinase occurred after exerci se. Basal HSP expression was usually lower in trained compared with untrain ed subjects. Applying in vitro heat shock to resting blood samples of all s ubjects significantly stimulated HSP mRNA, showing higher increases in trai ned individuals. The exercise-induced alterations indicate that immunocompe tent cells became activated. In addition to heat stress, other exercise-ass ociated stress agents (oxidants, cytokines) may have also participated in s timulation of RSP expression in leukocytes. The expression pattern of HSP d ue to training status may be attributed to adaptive mechanisms.