Research On Antihypertensive Effect And Mechanism Of The Extraction Of Peritrophe Roxburghiana In Renal Hypertensive Rats

AIMS: To observe the effect of the extraction of Peristrophe roxburghiana on renal hypertensive rats, and investigate its antihypertensive mechanism.METHODS: Sprague-Dawley rats received food and water ad libitum in 1 week of acclimation. After that, baseline blood pressure (BP) was measured by noninvasive tail cuff photosensor. Under aseptic conditions, thirty general anesthesia rats were given a modified 2 kidney-1 clip (2K1C) operation while six rats were sham-operated (The animals received identical treatment without left renal artery ligation). Four weeks later, twenty four hypertensive rats were randomly allocated to four groups such as HSX(higher, LD50/30, equal to herb 1.14 g / kg), HSX(lower, LD50/90, equal to herb 0.38 g / kg), Captopril(Cap, 20 mg/kg) and model group. After allocation, drugs were administered in a single dose of 0.1 ml/kg body weight by ig, respectively. Rats in model or sham group were administrated with identical volume of distilled water. The treatment period was 4 weeks. The blood pressure was measured weekly. In the 4th week, the nitric oxide(NO) in urine were measured too. At sacrifice, blood was harvested to measure the levels of angiotensin II (Ang II), NO, nitric oxide synthase (NOS) and endothelin(ET) at the end of the 4th week, angiotensin II (Ang II) in the kidney and the heart tissues was also measured. Kidneys and hearts were collected to observe the pathological changes of arteriole too.RESULTS: Four weeks after 2K1C operation, the blood pressure of the model rats increased significantly(17.32 2.4KPa vs!13.14 .92KPa of sham group, P<0.01). Treated with Cap and HSX , the blood pressure decreased significantly and continually(P<0.05 or P<0.01). During the course of administration, Heart rate (HR) didn't change markedly. In model group, Ang II in plasma didn't change but increased remarkably in heart and kidney tissues. Meanwhile, ET and NO, NOS in plasma increased and decreased, respectively. In HSX(H and L) groups, Ang II (inheart and kidney tissues) and ET decreased significantly(vs model group, P < 0.05 or P < 0.01), NO and NOS values increased markedly(vs model group, P < 0.05 or P < 0.01). Due to the short course of experiment, the pathological change of coronary artery and renal artery was not seen under the microscope.CONCLUSIONS: HSX can reduce the blood pressure of the renal hypertensive rat, which is likely related to RAS and ET/NO, and has no effect on the HR. It should be more than one antihypertensive target of HSX .