Influence Of 20-Hydroxyecdysone On Skeletal Muscle Inflammation Following Eccentric Damage

Inflammation plays an important role in the skeletal muscle repair process after damage. In addition to exerting anabolic/growth effects on skeletal muscle, phytoecdysteroids, like 20-hydroxyecdysone (20E), have been reported to possess anti-inflammatory properties. The purpose of this study was to investigate the influence of 20E on the inflammatory response to eccentric damage in mouse skeletal muscle. Male mice (3-6 months of age) were (DHR) or were not (No DHR) subjected to eccentric damage via an acute bout of downhill running to exhaustion. Mice were treated daily with 20E (50mg/Kg body mass) or vehicle for two or five days, and sacrificed on the next day. Using immunohistochemical techniques, expression of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) were examined in fresh-frozen gastrocnemius muscles. From a semi-quantitative analysis, treatment of 20E was seen to reduce expression of IL-6 and MCP-1 following an acute bout of DHR; which indicates that 20E may exhibit anti-inflammatory activity in response to skeletal muscle damage. These results, previous work in our lab, and the overwhelming amount of literature showing anabolic effects of 20E, suggest that there may be a novel mechanism allowing both catabolic and anabolic steroid-like activity.