Objective To observe the effect of electroacupuncture(EA)on expression of high mobility group protein 1(HMGB 1)and related downstream effectors of proinflammatory cytokines in the hippocampus in chronic neuropathic pain rats

so as to investigate its mechanism underlying neuropathic pain relief.Methods Male SD rats were randomized into sham

model

and EA groups

with 12 rats in each group.The neuropathic pain model was established by ligature of the left sciatic nerve to induce chronic constriction injury(CCI).EA was applied to bilateral"Zusanli"(ST 36)and "Yanglingquan"(GB 34)for 30 min

once daily for 7 days.The mechanical withdrawal threshold(WMT)was detected using an electronic von Frey anesthesiometer.The expression level of HMGB 1 in the hippocampus was determined using quantitative RT-PCR and Western blot

separately

and the contents of hippocampal TNF-αand IL-1β were detected by ELISA.Results Compared with the sham group

the MWT values were markedly decreased on day 7

10 and 14 after modeling in the model group(P<0.001).On day 10 and 14 after modeling

the MWT values were significantly up-regulated in the EA group relevant to those of the model group(P<0.05

P<0.01).The expression levels of HMGB1 mRNA and protein

and the contents of hippocampal TNF-αand IL-1βwere markedly increased in the model group relevant to the sham group(P<0.001)

and significantly down-regulated in the EA group relevant to the model group(P<0.001

P<0.01

P<0.05).Conclusion EA stimulation of ST 36-GB 34 can relieve pain in chronic neuropathic pain rats

which may be related to its actions in down-regulating the levels of HMGB 1 and its downstream proinflammatory cytokines TNF-αand IL-1βin the hippocampus.