Effect of Electroacupuncture on Spinal Cord Injury in Mice: Inhibition Of Inflammatory Response and Oxidative Stress via ApoE and Nrf2

Abstract

Background: Spinal cord injury (SCI) is a catastrophic central nervous system disease. Inflammatory response and oxidative stress are two critical factors in the pathophysiological process of SCI and closely involved with Apolipoprotein E(ApoE) and Nuclear factor erythroid 2-related factor (Nrf2). Electroacupuncture (EA) has perfectly neuroprotective effect on SCI. However, the underlying mechanism by which EA mediates the inflammatory response and oxidative stress is not completely elucidated. In the present study, we investigated the signaling pathways that EA regulates inflammatory response and oxidative stress through elevation of ApoE and Nrf2 after SCI.Methods: C57BL/6 Wide Type (WT) mice and ApoE -/- mice were subjected to SCI model by a serrefine clamping. Neurological function was detected by BMS scores, ultrastructure of demyelinationed axons was observed by transmission electron microscopy. ApoE, pro- and anti- inflammatory cytokines, oxidative stress-relevant proteins were determined by histochemistry technology. Two-way ANOVA was applied to BMS scores. One-way ANOVA and Bonferroni's multiple comparison test were used to analyse differences among groups.Results: BMS scores were increased gradually and demyelinated axons were improved by EA gradually with the expression of ApoE. EA can inhibit inflammatory response by activation of ApoE, which decreased pro-inflammatory cytokines(TNF-α, IL-6, and IL-1β) expression and increased anti-inflammatory cytokines(IL-10 and TGF-β1).Meanwhile, EA can also inhibit oxidative stress by elevation of Nrf2,which induced HO-1 and NQO1 expression in WT and ApoE -/- mice.Conclusions: EA is a reliable treatment for promoting functional recovery of SCI. Thesynergisticrole of ApoE and Nrf2 in EA regulating inflammatory response and oxidative stress is decisiveto recovery after SCI.