Abstract
Effects of hindlimb immobilization (HI) on the expression of Akt and GSK-3β, a downstream of Akt, during the regenerating process were investigated in mouse skeletal muscle. Male mice (C57BL/6J) were divided randomly into 4 groups: normal control, and with cardiotoxin (CTX)-injection, HI, and both CTX-injection and HI. CTX (0.1 ml, 0.1 mM) was injected into the left tibialis anterior (TA) muscle. The immobilization of left ankle joint at a plantar-flexed position using plaster cast in mice, with or without CTX injection, was also performed. TA muscles were dissected after 7, 14, and 28 days. Regeneration-related increases of wet weight and protein content in TA and muscle satellite cells were significantly inhibited by HI. The activation of Akt and the inactivation of GSK-3β were observed during regenerative process. The inactivation of GSK-3β was not observed in the HI group. It is suggested that the inactivation of GSK-3β may be a key signal for the regeneration of injured skeletal muscle. This study was supported, in part, by Grant-in-Aid for Scientific Research (C, 17500444; A, 18200042; S, 19100009) from Japan Society for the Promotion of Science, Ground-based Research Program for Space Utilization from Japan Space Forum. [J Physiol Sci. 2008;58 Suppl:S68]
