Electroacupuncture promotes angiogenesis in MIRI rats by modulating the AMPK/KLF2 signaling pathway

Abstract

To observe the effect of electroacupuncture(EA) on adenosine 5'-monophosphate-activated protein kinase (AMPK)/Kruppel-like factor 2 (KLF2) signaling pathway in ischemic myocardial tissues of rats, so as to explore the underlying mechanism of EA in attenuating myocardial ischemia-reperfusion injury (MIRI) through mediating angiogenesis. Male SD rats were randomly divided into sham operation group, model group and EA group, with 10 rats in each group. The MIRI model was established by ligation of the anterior descending branch of the left coronary artery. Twenty-four hours after modeling, the rats in the EA group were given EA (2 Hz/100 Hz, 2 mA) at "Neiguan" (PC6) for 20 min each time, once a day for 5 consecutive days. Echocardiography was used to detect cardiac ejection fraction (EF) to evaluate cardiac function. HE staining was used to observe the morphological changes in rat myocardial tissue. Immunohistochemistry was used to detect the density of neovascularization in rat ischemic myocardium. Western blot and ELISA were used to detect the phosphorylated(p)-AMPK, AMPK, KLF2, vascular endothelial growth factor (VEGF) protein expression levels, and VEGF receptor 2 (VEGFR2) content in rat ischemic myocardial tissue, respectively. After modeling, compared with the sham operation group, rats in the model group had decreased EF(P<0.01), significant myocardial fiber damage with inflammatory cell infiltration, increased neovascular density (P<0.05), increased p-AMPK, AMPK, VEGF protein expression levels and VEGFR2 content in myocardial ischemic tissues(P<0.05, P<0.01), and decreased protein expression level of KLF2 (P<0.05). After EA intervention, compared with the model group, rats in the EA group had elevated EF(P<0.01), significantly reduced myocardial fiber damage, reduced inflammatory cell infiltration, increased neovascular density(P<0.01), and elevated p-AMPK, AMPK, KLF2, and VEGF protein expression levels and VEGFR2 content in the myocardial ischemic tissue (P<0.01). EA may promote angiogenesis, attenuate myocardial injury, and achieve cardioprotective effects in MIRI rats by regulating the expression of AMPK/KLF2 signaling pathway in myocardial tissues.