Diathermy treatment increases heat shock protein expression in female, but not male skeletal muscle

Heat shock treatments have been used to appreciably increase heat shock protein 70 (Hsp70) content and the phosphorylation of heat shock protein 27 (Hsp27p). The purpose of this investigation was to determine whether diathermy can increase Hsp70 and Hsp27p content in skeletal muscle. Fourteen subjects (7 males and 7 females, 18-35 years) received a muscle biopsy from the v. lateralis and then underwent 20 min of diathermy followed by 20 min of hot pack heating on the contralateral leg. Twenty-four hours following treatment, a second muscle biopsy was performed on the treated leg. All samples were analyzed for Hsp70 and Hsp27p content using western immunoblotting. Images of the blots were obtained and analyzed via densitometry. A paired t-test was used to examine differences in heat shock protein content between the treated and untreated legs. Twenty-four hours following the heat treatment, female subjects significantly (P < 0.05) increased Hsp70 (+58%) and Hsp27p (+100%) content compared to the untreated leg. Male subjects had non-significant increases in Hsp70 (+35%) and Hsp27p (+32%) skeletal muscle content. These results implicate that diathermy can be an effective means to induce Hsp70 and Hsp27p in human skeletal muscle.