Effect of electroacupuncture on myocardial infarct size and expression of inflammatory cytokines and sympathetic-active substances in the myocardial ischemic tissue of rats

Abstract

To investigate the effect of electroacupuncture (EA) on the expression of interleukin-8 (IL-8), interleukin-10 (IL-10), tyrosine hydroxylase (TH), β3-adrenergic receptor (β3AR), and endothelial nitric oxide synthase (eNOS) in myocardial tissue in ischemic myocardial injury rats, so as to reveal its underlying mechanisms in myocardial protection via anti-inflammation and sympathetic nerve remodeling. A total of 48 male Sprague-Dawley rats were randomly divided into sham-operation (sham, n＝9), sham ＋EA (n＝9), model (n＝15) and EA (n＝15) groups. The myocardial ischemia (MI) model was established by ligation of the left anterior descending branch of the left coronary artery. EA (2 Hz/15 Hz，1.5－2 mA) was applied to bilateral "Neiguan" (PC6) for 30 min, once daily for 4 days. The myocardial infarct size was detected by 2, 3, 5 triphenyltetrazolium chloride (TTC) staining, myocardial histopathological changes and inflammatory infiltration were assessed by H．E. staining, and the expression of IL-8, IL-10, TH, β3AR, and eNOS in the myocardium was determined by using Western blot. Compared with the sham group, a marked myocardial infarction was found in the left ventricle tissue, accompanied with disordered arrangement of myocardial fibers and higher degree of inflammatory cell infiltration, and increased expression of IL-8, TH, β3AR and eNOS in the myocardium in the model group (P<0.01), but without significant change in the expression of IL-10 (P>0.05). After EA intervention and in comparison with the model group, the myocardial infarct size was significantly reduced (P<0.01), the severity of inflammatory cell infiltration and disordered arrangement of myocardial fibers were relieved, and the expression of IL-10 and eNOS proteins were significantly up-regulated (P<0.05), and the markedly up-regulated expression of IL-8, TH, and β3AR were significantly suppressed in the EA group (P<0.01)．. EA intervention can reduce the myocardial infarct size (protective effect) in MI rats possibly by reducing inflammatory reaction and sympathetic nerve remodeling.