Electroacupuncture Pretreatment Attenuates Acute Lung Injury Through α7 Nicotinic Acetylcholine Receptor-Mediated Inhibition of HMGB1 Release in Rats After Cardiopulmonary Bypass

Acute lung injury is a common complication after cardiopulmonary bypass (CPB). α7 Nicotinic acetylcholine receptors (α7nAChR) and α7nAChR-dependent cholinergic signaling are implicated in suppressing the release of high-mobility group box 1 (HMGB1) and reducing the inflammatory response. A previous study has shown the electroacupuncture (EA) pretreatment induces tolerance against lung injury. However, the role of EA in CPB is poorly understood. This study used EA and a rat model of CPB to determine whether EA was associated with CPB-induced lung injury. Rats were treated with EA at "Zusanli (ST36)" and "Feishu (BL13)" acupoints for 5 days before being subjected to CPB. Two hours post-CPB, samples of blood, bronchoalveolar lavage fluid (BALF), and lung tissues were processed for investigations. Our results showed that the expression of α7nAChR in lung tissue was significantly decreased after CPB. EA pretreatment prevented the reduction in the expression of α7nAChR, EA pretreatment reduced lung edema, inhibited inflammatory cytokines release in serum and lung as well as protein concentrations in BALF and HMGB1 release after CPB, and the beneficial effects were attenuated by α-BGT. Our study demonstrates that EA pretreatment plays a protective role in CPB-induced ALI, and inhibits HMGB1 release through α7nAChR activation in rats.