Resveratrol alleviates obesity-induced skeletal muscle inflammation via decreasing M1 macrophage polarization and increasing the regulatory T cell population

Resveratrol was reported to inhibit inflammatory responses; however, the role of this polyphenol in obesity-induced skeletal muscle inflammation remains unknown. Mice fed a high fat diet (HFD) were treated with resveratrol for 16 weeks. Resveratrol treatment decreased macrophage infiltration into skeletal muscle of HFD-fed mice. Resveratrol also led to the polarization of macrophages to the M2 direction, as well as decreasing the expression of a number of M1 pro-inflammatory cytokines [tumor necrosis factor α (TNF-α), interleukin 1 β (IL-1β) and interleukin 6 (IL-6)]. In addition, increased infiltration of regulatory T cells (Treg cells) was found following resveratrol treatment in skeletal muscle of mice. Decreased intramyocellular lipid deposition was associated with reduced expression levels of toll-like receptors 2 (TLR2) and TLR4 in resveratrol treated mice. We also found that diminished inflammation in skeletal muscle following resveratrol treatment was accompanied by increasing phosphorylation of 5’-adenosine monophosphate-activated protein kinase (AMPK) and decreasing phosphorylation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Taken together, these findings suggest that resveratrol ameliorates inflammation in skeletal muscle of HFD-induced model of obesity. Therefore, resveratrol might represent a potential treatment for attenuation of inflammation in skeletal muscle tissue.