Effects Of Valsartan And Benazepril On ACE,AT₁R,AT₂R Expression In Heart, Kidney Of Spontaneously Hypertensive Rats

[Objective]To investigate the effects of benazepril and valsartan onACE, AT1R, AT2R expression in heart, kidney of spontaneously hypertensive rats(SHR) and to explore the role ofACE, AT1R, AT2R in the pathogenesis of hypertension.[Methods](1) 24 12-week-old male SHR were allocated to four groups at random as followed (each group n=6): a. control group(distilled water ig.) (SHRc) b. benazepril group(10mg/kg/d ig.) (SHRb) c. small-dose valsartan group(10mg/kg/d ig.) (SHRsv) d. large-dose valsartan group(30mg/kg/d ig.) (SHR1v). Treatment lasted three months. Blood pressure and body weight of SIIR were measured once a month. Rats were killed at the end of treatment and the weights of the whole heart and left ventricle, which were used to calculate the ratio of the heart weight to body weight(H/B) and the left ventricle mass index(LVMI), were measured. (2)The heart, kidney of rats were embeded with paraffin. Collagen of the heart was stained by sirius red to observe the effects of the drugs on myocardial fibrosis. ACE, AT1R, AT2R expression level in kidney ,heart were compared by immunohistochemistry.[Results](1)Benazepril and valsartan treatment significantly decreased the blood pressure, H/B and LVMI of SHR, especially in SHR1v group(p<0. 05). (2) Benazepril and valsartan treatment significantly decreased thecontent of collagen in the heart of SHR, especially in SHR1v group. (3) Benazepril treatment slightly decreased expression of AT1R in kidney and heart of SHR .while valsartan intervention notably decreased its expression level, which was more significant in SHR1v than SHRsv(p<0.05). (4) Valsartan intervention significantly incrcased expression levels of AT2R in heart, kidney of SHR, especially in SHR1v group(p<0.05), while benazepril treatment had no effect on the expression of AT2R in heart, kidney of SHR. (5) Benazepril treatment increased expression of ACE in kidney and heart of SllR; while valsartan intervention increased ACE expression in kidney. [Conclusions]Benazepril and valsartan treatment effectly decrease the blood pressure of SHR, relieve left ventricular hypertrophy and attenuate myocardial fibrosis in the heart of SHR. Benazepril treatment decreased expression of AT1R in the kidney and heart of SHR ,while there was no effect on the expression of AT2R. Valsartan therapy decreased expression of AT1R in the kidney and heart of SHR, and increase the expression level of AT2R in these organs. AT2R expression in these organs is associated with the regulation of blood pressure and the protection of target organs.