Effects of Electroacupuncture on Expression of Myocardial Chloride Channel-2 and CLCA Proteins in Mice with Acute Myocardial Ischemia

OBJECTIVE: To observe the influence of electroacupuncture stimulation (EA) of "Neiguan" (PC 6)/"Lieque" (LU 7) on ST segment of electrocardiogram (ECG) and the expression of myocardiac chloride channel (CLC)-2 and calcium (Ca2+)-activated chloride channel accessory (CLCA) proteins in acute myocardial ischemia (AMI) mice, so as to explore its mechanisms underlying improvement of AMI. METHODS: Thirty ASIC 3-/- knock out mice were randomly divided into control, AMI model, EA-Neiguan (PC 6), EA-Lieque (LU 7) and EA-non-acupoint groups. The AMI model was induced by multiple subcuta-neous injection of isoprenaline (ISO, 0.5 g/L, 20 mg/kg). EA was applied to bilateral PC 6, LU 7, or non-acupoint[the mid-point between "Tianshu" (ST 25) and "Shenque" (CV 8)] for 20 min, once daily for 7 days. The ST segment of ECG of the standard Ⅱlimb-lead was recorded using a PowerLab data acquisition device, the change of myocardial histology observed by using microscope after HE staining, the activity of serum superoxide dismutase (SOD) detected using Colorimetric method, and the expression of CLC-2 and CLCA proteins of the left ventricle myocardium detected by Western blot. RESULTS: Outcomes of HE staining showed that the ischemic injury (sarcoplasm swelling and necrosis, etc.) of the left ventrical myocardial tissue after mo-deling was relatively milder in the EA-PC 6 group, not in the EA-non-acupoint group. The SOD activity was significantly lower in the model group than in the control group (P 0.05). The expression levels of myocardial CLC-2 and CLCA proteins were significantly up-regulated in the model group compared with the control group (P<0.01) and markedly down-regulated in the EA-PC 6 group (not in the EA-non-acupoint group) in comparison with the model group(P<0.01), suggesting a specificity of effects of EA-PC 6 in improving myocardial injury and down-regulating CLC-2 and CLCA protein expression. CONCLUSIONS: EA of "Neiguan" (PC 6) can effectively suppress the increase of expression of CLC-2 and CLCA proteins in the left ventricle myocardium, which may contribute to its effect in relieving myocardial injury in mice.