Role of Cooling Recruitment on Skeletal Muscle Hspb1 Gene Expression during Recovery from Eccentric Contractions

Abstract

Background and Objectives: In recent years, the use of cold water immersion (CWI) following heavy training sessions has become a common habit among athletes aiming to reduce soreness, but there aren't strong scientific rational behind this belief. Hspb1 gene, which expressing heat shock protein 25 has an important role in recovery and adaptation to exercise. The aim of this study is to investigate the Hspb1 gene expression following post eccentric exercise cooling, during primary and late recovery. Materials and Methods: Fourthy male Wistar rats (n=40; W= 300±10gr) were divided into two groups of exercise (Ex group) and exercise with cold water immersed group (Ex+CWI). Each group furture subdivided in to three subgroups based on three time-courses (0, 3, and 48 h after exercise). Exercise consists of 90 min interval downhill running (18*5 min, 2 min rest between intervals, 20m/min, and 17˚ decline). Post exercise cooling consists of 10 min of cold water immersion in 10˚C water. Hspb1mRNA level was measured in soleus muscle using Real-Time PCR. The results were studied by statistical methods. Results: Gene expression of Hspb1 increased 3 hour’s after exercise in both groups, but the difference between two groups was not significant in this time course. However Hspb1mRNAexpression in Ex+CWI group 48 hr after-exercise was significantly less than Ex group (P=0.016). Conclusion: This study indicates that cooling after eccentric contraction. Exercise may suppress Hspb1 gene expression during late recovery period and interfere with protective role of this gene during the recovery of skeletal muscle after exercise.

Keywords: Hspb1 gene, Cold Water Immersion (CWI), Downhill Running