Changes in α7β1 integrin signaling after eccentric exercise in heat-shocked rat soleus

Introduction: α7β1 integrin links the extracellular matrix to the focal adhesion (FA) in skeletal muscle and serves as a stabilizing and signal relayer. Heat shock (HS) induces expression of proteins that interact with the FA. Methods: Male Wistar rats were assigned to 1 of 3 groups: control (CON); eccentric exercise (EE); or EE+HS (HS). Soleus muscle was analyzed at 2 h and 48 h post-exercise. Results: The 120-kDa α7 integrin decreased in the EE and HS groups, and the 70-kDa peptide decreased in the EE group at 2 h post-exercise. Total expression of focal adhesion kinase (FAK) and RhoA were decreased in EE and HS at 2 h post-exercise. Expression of phosphorylated FAK³⁹⁷ decreased in the EE group but not the HS group at 2 h post-exercise. Conclusions: Long-duration EE may cause alterations in the FA in rat soleus muscle through the α7 integrin subunit and FAK.