Antihypertension and cardio-protective effect of Zusanli and Taichong in spontaneously hypertensive rats

Abstract

Objective This study aims to explore antihypertension and heart protective effect of acupuncture on SHR rats through the observation of blood pressure, cardiac ultrasound and pathology examination of SHR rats after needling the Zusanli (ST 36) and Taichong (LR 3). Methods A total of 14 SHR rats (10 weeks) were randomly divided into two groups: 6 for model group and 8 for acupuncture group, another 6 SD rats (10 weeks) were used as the control group. SHR rats in the acupuncture group were fixed in the holder, and then they exposed both lower limbs for needling both sides Zusanli (ST 36) and Taichong (LR 3), and then they retained needles for 20 minutes per time with four weeks. The other two groups were fixed in the holder without needling. Blood pressure was examined each week. LVSs, LVDd, LVPWs, LVPWd were measured and recorded by cardiac ultrasound in the day after the whole course of acupuncture. LVM, LVMI, RWT were calculated. The hearts of rats were dissected and fixed in formalin for heart pathology detection after doing the cardiac ultrasound. Results After acupuncture treatment, compared with model group, the systolic blood pressure (SBP) of the third week (178.38 ± 9.47 mmHg vs. 190.00 ± 13.90 mmHg) and the fourth week (167.96 ± 23.47 mmHg vs. 195.47 ± 11.36 mmHg) of acupuncture group significantly decreased (P<0.01). The diastolic pressure (DBP) of the third week (139.33 ± 13.20 mmHg vs. 159.56 ± 12.89 mmHg) and the fourth week (132.92 ± 18.02 mmHg vs. 165.61 ± 13.36 mmHg) of acupuncture group significantly decreased (P<0.01). The LVSs (0.96 ± 0.07 vs. 1.28 ± 0.24), LVPWs (1.15 ± 0.08 vs. 1.68 ± 0.19) of the acupuncture group were significantly lower than those of the model group (P<0.01). The LVM (0.51 ± 0.12 vs. 0.84 ± 0.17) and LVMI (14.96 ± 1.53 vs. 23.65 ± 5.04) of acupuncture group were significantly lower than those of the model group (P<0.01). Histopathologic examination of the heart of the model group showed chronic inflammatory granulation tissue hyperplasia and fibrosis in myocardial outer membrane, but the acupuncture group showed no obvious changes in the heart tissue. Conclusions Acupuncture treatment on Zusanli (ST 36) and Taichong (LR 3) could effectively control the left ventricular hypertrophy by decreasing the SBP and DBP , prevent cardiac remodeling, and protect myocardial cells. Key words: Acupuncture; Hypertension; Point ST36 (Zusanli); Point LR3 (Taichong); Rats, inbred SHR