电针累积镇痛效应的机制:基于AMPK信号通路的靶向调控研究OA

Objective To explore the molecular mechanism of cumulative analgesic effect induced by repeated electroacupuncture(EA)intervention via targeted regulation of adenosine monophosphate-activated protein kinase(AMPK)signaling pathway.Methods Mice were randomly divided into control group,model group,single EA group,repeated EA group and sham EA group;as well as vehicle+EA group and inhibitor+EA group,with 8 mice in each group.A mice inflammatory pain model was established by complete Freund's adjuvant(CFA)injection.Repeated EA stimulation was applied to mice in repeated EA group,vehicle+EA group and inhibitor+EA group at left"Zusanli"(ST36)and"Shangjuxu"(ST37).The parameters were set as frequency 2 Hz,current 1 mA,30 min per intervention,once a day for 6 consecutive days.The single EA group only received a single EA treatment on the second day after modeling.The sham EA group only received superficial subcutaneous puncture without electrical stimulation.Mice in inhibitor+EA group were intraperitoneally injected with Compound C at a dose of 20 mg/kg 30 minutes before daily EA.Mechanical pain threshold and thermal pain latency were detected to evaluate pain behaviors.Western blot was used to determine the protein expression levels of p-AMPK,AMPK and c-Fos in the spinal dorsal horn.Immunofluorescence staining was adopted to detect the number of c-Fos positive cells.Results Compared with the control group,mechanical pain threshold and thermal pain latency were markedly decreased in the model group(P<0.05).Compared with the model group,single EA significantly elevated mechanical pain threshold and thermal pain latency at 1,2 and 4 h after treatment(P<0.05);repeated EA increased pain thresholds after intervention(P<0.05).The ratio of p-AMPK/AMPK in lumbar spinal dorsal horn was significantly higher in repeated EA group than that in control and model groups(P<0.05),while this indicator was obviously lower in sham EA group than that in the EA group(P<0.05).Pain thresholds from day 2 to day 6 were higher in vehicle+EA group relative to the model group(P<0.05),and notably declined in inhibitor+EA group compared with vehicle+EA group(P<0.05).The expression level and positive neuron number of c-Fos were increased in the model group versus the control group(P<0.05),and reduced in vehicle+EA group(P<0.05).Such changes were reversed after Compound C intervention(P<0.05).Conclusion Repeated EA can effectively alleviate CFA-induced pain in mice.The cumulative analgesic effect may be mediated by persistent activation of AMPK in the lumbar spinal dorsal horn.