Effect of Electroacupuncture Stimulation of Heart and Lung Meridians on Expression of Myocardial HCN 2 in Acute Myocardial Ischemia Rats

Abstract

To observe the effect of electroacupuncture (EA) stimulation of Heart and Lung meridians on the expression of hyperpolarization-activated cyclic nucleotide gated potassium channel 2 (HCN 2) mRNA and protein in the myocar-dium of the left ventricle in acute myocardial ischemia (AMI) rats, so as to underlying its mechanism in improving ischemic myocardial injury. A total of 120 male SD rats were randomly divided into normal control, model, EA-Heart Meridian (HT) and EA-Lung Meridian (LU) groups (n＝30 rats in each group). The AMI model was established by occlusion of the anterior descending branch of coronary artery. EA (1 mA, 10 Hz) was applied to bilateral "Shenmen" (HT 7) or "Taiyuan" (LU 9) and the spot about 1 mm apart from the HT 7 or LU 9 on the axopetal end for 15 min on the second day after modeling, once a day for 7 days. The left ventricular myocardium tissue was sampled for determining the expression levels of HCN 2 mRNA and protein with qPCR and Western blot, separately. After AMI, both HCN 2 mRNA and protein expression levels in the model group were significantly decreased in comparison with the normal control group (P<0.01). Following EA intervention, the expression levels of HCN 2 mRNA and protein expressions were significantly up-regulated relevant to the model group (P<0.01)．The effects were more obvious in the EA-HT group than in the EA-LU group, and the expression levels were higher in the left ventricular myocardium tissue sampled on the next day after the treatment than those in the tissue sampled immediately after the treatment (P<0.01). Both EA stimulation of Heart Meridian and Lung Meridian can improve the expression of HCN 2 mRNA and protein in the myocardium in AMI rats, which existing a delayed effect and meridian specificity.