Objective To explore the effect of electroacupuncture(EA)on the expression of synovial AMP-activated protein kinase(AMPK)proteinα

arginase-1 mRNA

nitric oxide synthase 2(NOS 2)mRNA

NOD-like receptor protein 3(NLRP 3)mRNA

and interleukin-1β(IL-1β)mRNA in acute gouty arthritis(AGA)rats

so as to explore its mechanisms underlying improvement of AGA via M 1/M 2 macrophage polarization.Methods Male Wistar rats were randomly divided into normal control

model

medication(colchicine)and EA groups(n=15 rats in each group).The AGA model was established by injection of sodium urate crystal(MSU)suspension(0.2 mL)into the articular cavity of the left knee.The rats of the normal control group received articular injection of normal saline(0.2 mL)of the left knee

and those of the medication group were treated by gavage of the colchicine(0.3 mg·kg-1·d-1)once daily for 7 days.EA(2 Hz/10 Hz

1.0 mA)was applied to"Zusanli"(ST 36)and"Sanyinjiao"(SP 6)of the left hind limb for 10 min

once daily for 7 days.The inflammatory conditions of the synovial membrane tissue of the left knee joint were observed by H.E.staining.The expression levels of phosphorylated AMPKα(p-AMPKα)protein

and arginase-1(a maker of M 2 macrophages)mRNA

NOS 2(a maker of M 1 macrophages)mRNA

NLRP 3 mRNA

and IL-1βmRNA in the knee joint synovial tissue were detected by Western blot and quantitative real-time PCR

respectively.Results Compared with the normal group

the inflammatory cell infiltration of the synovial tissue was more severe

the expression of p-AMPKαprotein was significantly decreased(P<0.01)

and the expression levels of arginase-1

NOS 2

IL-1βand NLRP 3 mRNAs were considerably increased in the model group(P<0.01).The expression levels of p-AMPKαprotein and arginase-1 mRNA were significantly up-regulated

and those of NOS 2

IL-1βand NLRP 3 mRNAs obviously down-regulated in both EA and medication groups relevant to the model group(P<0.01

P<0.05)

suggesting an increase of M 2 macrophage and a decrease of M 1 macrophage activity after EA.No significant differences were found between the EA and medication groups in up-regulating p-AMPKαexpression and in down-regulating NOS 2

IL-1βand NLRP 3 mRNA expression(P>0.05)

except higher up-regulation of arginase-1 mRNA in the medication group(P<0.05).Conclusion EA intervention can up-regulate the expression of arginase-1 mRNA and p-AMPKαprotein

and down-regulate the expression of NOS 2

IL-1βand NLRP 3 mRNAs in synovial tissues in AGA rats

which may contribute to its anti-inflammatory effect by promoting conversion of macrophages from M 1 pro-inflammatory phenotype to M 2 anti-inflammatory phenotype.