ABSTRACT
Objective To investigate the effects of quercetin with a special focus on their effect on macrophage po-larization after SCI.Methods Adult C57 mice underwent T10 spinal cord clip compression injury,then were ran-domly divided into SCI group and quercetin group.1-14 d after SCI received quercetin by intraperitoneal injection(once a day)in quercetin group,and received same normal saline in the SCI group.3,7 and 14 d after SCI, the lesion section of SCI group and Quercetin group stained by immunofluorescent:M1 macrophages pheno-type cell labeled with iNOS, and M2 macrophages phenotype cell labeled with Arg1.The mRNA expression of inflammatory factors in lesion site was detected by RT-PCR.The motor function was evaluated by Basso mouse scale(BMS)after SCI.Results Compare with SCI group,the expression of arginase-1(associated with M2 mac-rophage phenotype)significantly increased in quercetin group(P<0.05).The expression of inducible nitric oxide synthase-iNOS(M1 phenotype marker)was down-regulated as demonstrated using immunohisto-chemistry(P<0.05).Furthermore,the production of NOS2 and tumor necrosis factor alpha was significantly reduced whereas the level of interleukin 10 and TGF-β were elevated in quercetin group(P<0.05).The time course of functional recov-ery revealed a gradual recovery in the subacute phase in quercetin group, little improvement was observed in SCI group(P<0.05).Conclusions It is found that quercetin may promote the shift of M1 to M2 phenotype and amelio-rate the inflammatory microenvironment.Furthermore,the roles of quercetin in immunity modulation may enhance neuroprotective effects and partially contribute to the locomotor functional recovery after SCI.