Effects Of Radix Astragali In Gansu Dingxi On Expressions Of Angiotensin Converting Anzyme 2 Of Kidney And Heart In Two-kidney And One-Clip Hypertensive Rats

Objective: To determine the expressions of angiotensin-converting enzyme 2 (ACE2) and angiotensin-converting enzyme (ACE) within kidney and heart in two-kidney and one-clip (2K1C) hypertensive rats and the changes of ACE2/ACE gene expression as well as angiotensin II by Radix Astragali and valsartan. To observe effects of Radix Astragali on blood pressure.Methods: The fifty adult♂Wistar rats were divided into 5 groups randomly: the control group (n=10), 2K1C hypertension group (n=10), 2K1C+Valsartan group [20mg/(kg·d)] (n=10), 2K1C+Radix Astragali group [20g/(kg·d)] (n=10) and 2K1C+ Radix Astragali group [10g/(kg·d)] (n=10) for 8 weeks. The mRNA expressions and the distributions of ACE2/ACE in kidney and heart were detected both by reverse transcription-polymerase chain raction (RT-PCR) and immunohistochemistry respectively. Renal AngII was evaluated with radioimmunoassay (RIA). The blood pressure was measured by tail-cuff method.Results:①ACE2 mRNA in kidney was found to be significantly decreased in the 2K1C hypertensive rats compared with those of the control group (0.282±0.025 vs 0.359±0.017, P=0.006).The ACE2 mRNA expressions increased in rats treated by Valsartan and Radix Astragali [20g/(kg·d)], [10g/(kg·d)] compared with those of the control group(0.403±0.009, P=0.000; 0.398±0.004, P=0.016; 0.391±0.006, P=0.028).②ACE2 and ACE were stained along renal cortical tubules. ACE2 is located in coronary artery endothelium and myocardial cell.The result about ACE2 was similar with that of immunohistochemistry and that of RT-PCR. ACE expressions was significantly increased in the 2K1C hypertensive rats compared with those of the control group (0.295±0.023 vs 0.208±0.017, P=0.000) and decreased in 2K1C±Valsartan and Radix Astragali [20g/(kg·d), 20g/(kg·d)] compared with those of the2K1C hypertension group (0.212±0.019, 0.225±0.022, 0.237±0.020; P=0.000).③AngII in renal tissue was lower in control group than that of other groups (380.21±58.21 vs 956.99±170.53, 909.72±102.16, 657.94±90.22, 814.57±102.60; P=0.000). The Radix Astragali [20g/(kg·d] could decrease renal AngII compared with those of 2K1C group and 2K1C±Valsartan group (P=0.001).④SBP in 2K1C group was higher than that of other groups (P=0.000). Valsartan and Radix Astragali could make SBP lower significantly (P=0.000). There is not statistically significant between the two group of Radix Astragali [20g/(kg·d), 10g/(kg·d)] (P=0.926).Conclusions: The ACE2 is down-regulated but ACE is up-regulated and the level of renal AngII is increased in 2K1C hypertensive rats. Radix Astragali and Valsartan can reverse these regulation and benefit to lower the SBP in 2K1C hypertensive rats.The AngII in renal tissue is higher in 2K1C hypertension group. The effects of Radix Astragali on SBP are obvious and dose depedent.