Electroacupuncture Attenuates Limb Ischemia–Reperfusion–Induced Lung Injury Via p38 Mitogen-Activated Protein Kinase–Nuclear Factor Erythroid-2–Related Factor-2/Heme Oxygenase Pathway

Abstract Background Electroacupuncture has been reported to protect the body from organ damages, but its mechanisms remain to be explored. This research was designed to investigate the function of electroacupuncture in lung injury resulted from hind limb ischemia–reperfusion (LIR) and whether p38 mitogen-activated protein kinase (p38 MAPK)–mediated nuclear factor erythroid-2–related factor-2 (Nrf2)/heme oxygenase (HO)-1 pathway contributes to the protective effect of electroacupuncture on LIR-originated lung damage. Materials and methods Rabbits were subjected to occluding femoral artery for 2 h. Then they received reperfusion for 4 h to establish lung injury model. Electroacupuncture stimulation was performed bilaterally at Feishu and Zusanli acupoints for 15 min once a day for 5 d before the experiment and throughout the hind LIR model performing in the experimental day. Blood samples and lung tissues were collected to examine the role of electroacupuncture treatment in inflammatory response, oxidative stress, and lung injury. Both the protein expression and the messenger RNA level of Nrf2 and HO-1 were detected. Results The results showed that electroacupuncture treatment remarkably alleviated lung injury, decreased inflammatory cytokines secretion, attenuated lung oxidative stress, increased the amount of Nrf2 and HO-1, and increased the ratio of phospho-p38 MAPK to p38 MAPK after LIR. However, the protective effects exerted by electroacupuncture were reversed to some extent by the preconditioning with SB203580, a p38 MAPK–specific inhibitor. Conclusions These results suggested that electroacupuncture could attenuate lung injury in rabbits subjected to LIR by inhibition of proinflammatory cytokine response and oxidative stress through activating p38 MAPK-mediated Nrf2/HO-1 pathway.