Molecular Mechanism Of THSG In Relieving Chronic Inflammatory Pain

Tetrahydroxystilbene glucoside(THSG)is one of the active ingredients of Polygonum multiflorum.It has been shown to exert a variety of pharmacological effects,including antioxidant,anti-aging,and anti-atherosclerosis.Because of its prominent anti-inflammatory effect,we explored whether THSG had analgesic effect.In this study,we used a model of chronic inflammatory pain caused by injecting complete Freund's adjuvant into the hind paw of mice.We found THSG relieved swelling and pain in the hindpaw of mice on a dose-dependent manner.In the anterior cingulate cortex,THSG suppressed the upregulation of GluN2B-containing N-methyl-D-aspar tate receptors and the downregulation of GluN2A-containing N-methyl-D-aspartate receptors caused by chronic inflammation.In addition,THSG increased Bcl-2 and decreased Bax and Caspase-3 expression by protecting neuronal survival.Furthermore,THSG inhibited the phosphorylation of p38 and the increase of nuclear factor ?B(NF-?B)and tumor necrosis factor a(TNF-a).Immunohistochemical staining revealed that THSG blocked the activation of microglia and reduced the release of proinflammatory cytokines TNF-?,interleukin 1?(IL-1?),and interleukin6(IL-6).In conclusion,this study demonstrated that THSG had a certain effect on alleviating complete Freund's adjuvant-induced chronic inflammatory pain.