Antihypertensive Effect of Tianmu Jiangya Powder on SHR Rats and Its Mechanism / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate the antihypertensive effect of Tianmu Jiangya powder and its related antihypertensive mechanism by using SHR rats as a model, and protein expressions provide an experimental basis for the clinical application of Tianmu Jiangya powder in the treatment of hypertension. Method:Sixty male SHR rats were randomly divided into six groups according to body weight after one week of adaptive feeding model group, valsartan group (12 mg·kg-1), captopril group (9 mg·kg-1), hydrochlorothiazide group (6 mg·kg-1), Tianmu Jiangya powder low and high-dose group (0.36, 1.44 g·kg-1), WKY rats were used as the normal group, and the intragastric administration lasted for 16 weeks. Softron BP-2010A intelligent non-invasive blood pressure meter was used to measure the systolic blood pressure (SBP)and heart rate (HR) of rat tail arteries. Adobe Photoshop CS5 software was used to analyze the left auricle and claw fixed selected areas to evaluate the effect on blood stasis syndrome. Vevo 2100 small animal ultrasound imaging system detects left ventricular ejection fraction (LVEF), left ventricular shortening (FS), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic volume (LVEDV), left ventricular end-systole dimension (LVIDs), left ventricular end-diastole dimension (LVIDd), interventricular septum end-systolic depth (IVSs), and interventricular septum end-diastolic depth (IVSd). Then the rats were sacrificed and the materials were taken (blood, heart, aorta, liver, kidney, tibia), and the weight of heart, liver, kidney and tibia length were measured and recorded. Hematoxylin-eosin (HE) staining was used to observe the pathological changes of the heart and thoracic aorta. Separation of serum and plasma, and determination of nitric oxide (NO) in serum by nitrate reductase method. Radioimmunoassay was used to detect plasma adrenaline/3 methoxyadrenaline (MN), urea (UREA), and uric acid (UA) contents. The expression of nitric oxide synthase(iNOS) and vascular endothelial growth factor(VEGF) protein in thoracic aorta of each group was detected and analyzed by immunohistochemical method. Result:Compared with normal group, the SBP and HR of the rats in model group were significantly increased (P<0.05). The r value of the claw was significantly reduced and the g value was significantly increased at 8 and 16 weeks (P<0.05). LVEF and FS significantly decreased, LVESV, LVIDs, IVSd increased significantly (P<0.05). Heart weight, heart weight /tibia length, liver weight and liver weight /tibia length, plasma of MN, UREA, and UA contents significantly increased, and promoted the expression of iNOS and VEGF proteins in the aortic (P<0.05). Compared with the model group, the Tianmu Jiangya powder administration group could continuously reduce SBP in SHR rats, maintain HR stability (P<0.05), significantly increase the claw of r value, lower the claw of g value(P<0.05). LVEF, FS significantly increased, LVEDV, LVESV, LVIDd and LVIDs significantly decreased (P<0.05), significantly increased serum NO content, decreased liver weight, liver weight/tibia length, plasma MN, UREA, UA content (P<0.05), and down-regulated the expression of iNOS and VEGF protein in the aorta(P<0.05). Conclusion:Tianmu Jiangya powder has a certain antihypertensive effect, and its mechanism may be mainly related to protecting heart function, improving vascular endothelial function, reducing catecholamines and sedative analgesia.