The effect of icaritin on skeletal muscle atrophy following mechanical unloading

Abstract

Skeletal muscle undergoes rapid and profound atrophy in response to decreased mechanical loading, e.g., limb immobilization, bed rest, denervation, hindlimb suspension and spaceflight. This study was to investigate the effect of icaritin (ICT) on skeletal muscle atrophy following hindlimb unloading (HU). Male adult rats were suspended by tail for 28 days to induce HU-related skeletal muscle atrophy. Rats were orally administered daily with ICT at low (80 mg/kg, Low-ICT) and high (120 mg/kg, High-ICT) doses throughout the HU period for a total of 28 days. Age-matched, weight-bearing rats served as the control (n = 8 for each group). The results showed that soleus muscle fiber cross-sectional area in High-ICT group was significantly larger than that in HU only group. The proportion of fast-twitch fibers in High-ICT group was lower than that in HU only group. Functional tests showed that the maximal tetanic force of soleus muscle in High-ICH group was remarkably higher than that in HU only group, and the contraction time and half relaxation time in High-ICT group didn't shorten as HU group did. Current data indicates that high dose of icaritin treatment could prevent skeletal muscle atrophy and delay the slow-to-fast muscle fiber type transformation following mechanical unloading.