WANG Xianª²Mei1, YANG Liª²Xia1, SONG Wuª²Zhan2, QI Feng1, GUO Chuangª²Ming1, SHI Yanª²Kun1, ZHAO Ying1, WEI Ling1, WANG Yan1

    1Department of Cardiology, 2Department of Nuclear Medicine, Kunming General Hospital, Chengdu Military Area Command, Kunming 650032, China

    ¡¾Abstract¡¿ AIM: To observe the effect of angiotensinª²converting enzyme inhibitor (benazepril) on intrarenal reninª²angiotensin system (RAS) in spontaneously hypertensive rats (SHR) and to explore the mechanism by which benazepril protects kidney from renal interstitial fibrosis. METHODS: The animals were randomly divided into 3 groups: spontaneously hypertensive rats treated with benazepril (SHRª²B) group and SHR group and Wistarª²Kyoto (WKY) group. Using the methods of pathological examination and computer processing, the renal collagen area in kidney was observed. The area of collagen was examined by the image analysis system. The renal local angiotensinª²converting enzyme (ACE) activity was detected by ultraª²violet spectrophotography. Renal angiotensin II (Ang II) concentration was measured by radioimmunoassay. The mRNA expressions of type Iª² and type IIIª² collagens in renal tissue were analyzed using the reverse transcriptaseª²polymerase chain reaction (RT-PCR). RESULTS: The area of collagen was significantly decreased in SHRª²B group compared to SHR group (P<0.01). The renal local ACE activities were (27.6¡À6.5) nmol/(min¡¤mg) in SHRª²B group and (53.4¡À8.2) nmol/(min¡¤mg) in SHR group and (25.3¡À6.9) nmol/(min¡¤mg) in WKY group; there was a significant decrease in SHRª²B group as compared with SHR group (P<0.01), and there was no significant difference between SHRª²B and WKY groups (P>0.05). The contents of Ang II in renal local tissue were also markedly lower in SHRª²B group than in SHR group[(49.3¡À16.1) ng/g vs (83.4¡À8.2) ng/g, P<0.01)]. There was no significant difference between SHRª²B and WKY (P>0.05). The relative levels of mRNA expressions of type Iª² and type IIIª² collagens in renal tissue were markedly lower in SHRª²B group than in SHR group (P<0.01, respectively). CONCLUSION: Benazepril could attenuate rat renal fibrogenesis by inhibiting the activity of the renal RAS and decreasing collagen synthesis in renal tissue. ......