Study Of Effects And Mechanism Of Electroacupuncture On Inflammatory Response And Oxidative Stress After Spinal Cord Injury In Mice

ObjectiveTo explore the curative effect and the related mechanism of electroacupuncture?EA?on spinal cord injury?SCI?in mice,we observed the effects of EA on motor function,inflammatory response,oxidative stress,gliosis,neurons and glial cells apoptosis,axonal demyelination and the expression of apolipoprotein E?ApoE?and Nrf2/HO-1 signaling pathway after SCI in C57BL/6 wild-type?WT?and ApoE knockout(ApoE^-/-)mice.MethodsFemale C57BL/6 wild type?WT?mice were randomly divided into five groups:normal group?WT Normal group?,sham operation group?WT Sham group?,control group?WT SCI group?,EA treatment group?WT EA group?and EA+ApoE mimetic peptide-COG112 group?WT EA+COG112group?.Homologous ApoE^-/-mice were randomly divided into three groups:normal group(ApoE^-/-Normal group),EA treatment group(ApoE^-/-EA group)and EA+COG112 group(ApoE^-/-EA+COG112 group).The normal groups received nothing dispose;the sham group underwent only a laminectomy from the 12^thh thoracic vertebra?T12?to the 2ⁿdd lumbar vertebra?L2?;and the SCI model was established by clamping the spinal cord of the 1^stt lumbar vertebra?L1?for 25 s with a serrefine after the laminectomy in other groups.The WT SCI group only had an operation with no treatment.The EA groups received an EA intervention?3 h after surgery,bilateral“Zusanli”?ST36?and“Sanyinjiao”?SP6?,10 min,once a day?.The EA+COG112 groups were given COG112 intervention?30 min after surgery,COG112 solution,1 mg/kg,twice a day,8 hours apart?and EA intervention?after the first COG112 intervention?.The spinal cord samples were taken at 7 and 28 days after injury.Basso Mouse Scale?BMS?score was used to evaluate the hindlimb motor function of the mice;HE staining was used to observe the histopathological morphology of the spinal cord near the epicenter;q-PCR was used to detect the relative mRNA levels of inflammatory mediator tumor necrosis factor-??TNF-??,Interleukin?IL?-6,IL-1?,IL-10 and transforming growth factor-?1?TGF-?1?;immunofluorescence?IF?staining was used to detect the proliferation of astrocytes in the spinal cord;Electron transmission microscope?TEM?was used to observe the ultrastructure the spinal cord;Western blot?WB?was used to detect the relative protein expression levels of glial fibrillary acidic protein?GFAP?,apoptosis-related proteins Bcl-2 and Bax,ApoE,and phosphorylation-extracellular regulatory protein kinase?p-ERK?,and Nrf2/HO-1 signaling pathway related factors including nuclear factor E2-related factor 2?Nrf2?,heme oxidase-1?HO-1?and NAD?P?H-quinone oxidoreductase 1?NQO1?.ResultsAt 7 and 28 days after SCI,compared with the WT Sham group,the BMS score in the WT SCI group was significantly reduced?P<0.05?;the pathological score and the relative density of GFAP were significantly increased?P<0.05?;the relative protein expression levels of GFAP,ApoE,p-ERK,Nrf2,and HO-1 were significantly increased?P<0.05?.Compared with the WT SCI group,the BMS score in the WT EA group was significantly increased?P<0.05?;the pathological score and the relative density of GFAP were significantly reduced?P<0.05?;the relative protein expression level of GFAP was significantly reduced?P<0.05?,while ApoE,p-ERK,Nrf2,and HO-1 were significantly increased?P<0.05?.Compared with 7 days after SCI,the BMS scores of the WT SCI and WT EA groups at 28 days after SCI were both significantly increased?P<0.05?;the histopathological scores and the relative density of GFAP were both significantly decreased?P<0.05?;the relative protein expression levels of GFAP were both significantly decreased?P<0.05?,while ApoE,p-ERK,Nrf2,and HO-1 were both significantly increased?P<0.05?.At 28 days after SCI,the relative protein expression level of ApoE was not detected in the ApoE^-/-EA+COG112 and ApoE^-/-EA groups.Compared with the WT EA+COG112 group,the relative protein expression level of ApoE in the WT EA group was significantly decreased?P<0.05?;the BMS scores of the WT EA and ApoE^-/-EA+COG112 groups were both significantly reduced?P<0.05?;the pathological scores and the ratios of axonal demyelination were both significantly increased?P<0.05?;the relative mRNA levels of TNF-?,IL-6 and IL-1?were both significantly increased?P<0.05?,while IL-10 and TGF-?1 were both significantly reduced?P<0.05?;the relative protein expression levels of Bcl-2,Nrf2,HO-1,NQO1 were both significantly reduced?P<0.05?,while Bax were both significantly increased?P<0.05?.Compared with the ApoE^-/-EA group,the BMS scores of the WT EA and ApoE^-/-EA+COG112 group were both significantly reduced?P<0.05?;the pathological scores and the ratios of axonal demyelination were both significantly increased?P<0.05?;the relative mRNA levels of TNF-?,IL-6 and IL-1?were both significantly increased?P<0.05?,while IL-10 and TGF-?1 were both significantly decreased?P<0.05?;the relative protein expression levels of Bcl-2,Nrf2,HO-1,NQO1 were both significantly reduced?P<0.05?,while Bax were both significantly increased?P<0.05?.ConclusionEA effectively inhibits inflammatory response,oxidative stress,gliosis,neurons and glial cells apoptosis and axonal demyelination after SCI by up-regulating the expression of ApoE and activating the Nrf2/HO-1signaling pathway to enhance the synergistic effect on the properties of anti-inflammatory and antioxidant stress,which promotes the recovery of hindlimb motor function in mice after SCI.