The Ameliorating Effects Of Long-term Electroacupuncture At Baihui (DU20) And Zusanli(ST36) On Blood Pressure And Myocardial Hypertrophy In Spontaneous Hypertension Rat And Underlying Mechanisms

The purpose of this study is to investigate the inhibitory effects of long term electroacupuncture stimulation at BaiHui (DU20) and ZuSanLi (ST36) on blood pressure, myocardial hypertrophy and myocardial fibrosis of spontaneous hypertension rat (SHR) and underlying mechanisms.6-weeks-old SHR or Wistar male rats were randomly divided into6groups, the control group (SHR/Wistar), the non-acupoint electroacupuncture stimulation group (SHR-NAP/Wistar-NAP) and the electroacupuncture stimulation at DU20and ST36group (SHR-AP/Wistar-AP), with24rats in each group. For SHR-AP/Wistar-AP group and SHR-NAP/Wistar-NAP group, the points locating is according to the Chinese Rat Acupoint Positioning Standard. For the control groups, the rats only were binding up without acupuncture and electrical stimulation. Blood pressure was determined before and at2,4,6, and8weeks after electroacupuncture treatment by the tail-cuff method. At the end of8th weekend, the ventricular thickness and heart function of the rat were detected utilizing echocardiography. The content of angiotensin â…¡ (Ang â…¡), endothelin-1(ET-1) and nitric oxide (NO) in the plasma were determined using enzyme-linked immunosorbent assay. Histological studies were also performed on the heart and the ascending aorta. The expression of angiotensin â…¡ type1receptor (AT1R), endothelin-1type A receptor (ETAR), endothelial nitric oxide synthase (eNOS) and induced nitric oxide synthase (iNOS) in rat myocardium and ascending aorta were investigated by the western blotting method. The results demonstrated that mean arterial pressure, aortic wall and ventricular thickness and heart/body weight ratio of SHR were significantly reduced with long term electroacupuncture stimulation at DU20and ST36. The content of Ang â…¡, ET-1in SHR plasma decreased while the content of NO increased after electroacupuncture treatment. Long term electroacupuncture significantly inhibited protein expression of AT1R, ETAR and iNOS in rat myocardium and ascending aorta, while enhanced the eNOS expression in SHR. The beneficial effects of long term electroacupuncture stimulation at DU20and ST36on heart function may be related to decrease the content of Ang â…¡ and ET-1while increase the content of NO in peripheral blood, and inhibit the protein expression of AT1R, ETAR, iNOS in cardiac muscle and aortic wall while enhance the expression of eNOS.