贝那普利对百草枯中毒大鼠肺纤维化的干预作用

Effect of benazepril on pulmonary fibrosis induced by paraquat poisoning in rats

目的观察贝那普利对百草枯中毒大鼠肺纤维化过程的影响并探讨其可能的作用机制。方法72只SPF级SD雄性大鼠按随机数字表法分为对照组、百草枯染毒组（一次性百草枯60mg／kg灌胃）和贝那普利干预组[一次性百草枯60mg／kg灌胃并予贝那普利10mg／（kg·d）灌胃]，每组24只。对照组用0．9％氯化钠注射液替代百草枯及贝那普利。各组于实验第3、7、14天分批随机处死8只动物，取肺组织行苏木素一伊红（HE）染色和Masson染色，观察大鼠肺泡炎、肺纤维化程度；免疫组织化学测胶原I、Ⅲ；定时定量聚合酶链反应检测血管紧张素转化酶（ACE）、血管紧张素Ⅱ1型受体（ATl）mRNA表达；酶联免疫吸附法检测肺组织血管紧张素Ⅱ（AngⅡ）蛋白表达。结果百草枯染毒组第3、7、14天大鼠肺组织ACEmRNA、AT1 mRNA及AngⅡ蛋白表达均较对照组增高[ACEmRNA分别为（3．15±0．13）比（1．02±0．01）、（3．88±0．21）比（1．05±0．02）、（4．16±0．12）比（1．03±0．01），AT1 mRNA分别为（1．53±0．23）比（1．00±0．01）、（2．92±0．05）比（1．06±0．03）、（3．62±0．03）比（1．08±0．05），Angll分另0为（10．55±0．24）μg／L比（3．00±0．12）斗g／L、（7．43±0．23）彬L比（3．05±0．16）彬L、（8．36±0．35）形L比（3．03±0．13）μg／L]；贝习B普利干预组[第3、7、14天ACEmRNA分别为（2．20±0．22）、（2．95±0．08）、（2．80-t-O．16），ATlmRNA分别为（1．32±0．01）、（2．05±0．17）、（2．53±0．22），Angll分别为（5．85±0．32）、（6．21±0．16）、（6．13±0．33）μg／L]与百草枯染毒组比，表达下调（P〈0．05）。贝那普利干预组第7天始肺泡炎和纤维化程度积分及胶原I、Ⅲ含量低于百草枯染毒组（P〈0．05）。结论局部。肾素-血管紧张素系统的激活可能参与百草枯中毒致肺纤维化的发病过程。贝那普利对百草枯中毒大鼠肺纤维化有一定阻抑作用，可能与其抑制局部ACE，减少AngⅡ生成有关。

Objective To study the effect of benazepril on rat model of pulmonary fibrosis caused by paraquat （PQ）, and explore its possible mechanism. Methods Seventy-two male sprague-dawley （SD） rats were randomly divided into three groups （n = 24 each）, including sham-operated, PQ and treatment （T） group. In PQ and T group, rats were administered intragastrically with a single dose （60 mg/kg） of PQ. After exposure, T group received intragastric injection of benazepril at a dose of 10 mg/（ kg.d）. Only saline was treated orally in the sham group. Rats were sacrificed and lungs were harvested at day 3, day 7 or day 14, respectively. The severity of pulmonary alveolitis and fibrosis were semiquantitated using histological scores based on HE staining and Masson staining. The expression of type I and II1 collagen were determined by immunohistochemistry. Quantitative real-time polymerase chain reaction （PCR） was used to access angiotensin converting enzyme （ ACE ） and angiotensin I （AT1） receptor gene expression. AT Ⅱ protein was detected by enzyme linked immunosorbent assay （ELISA）. Results In PQ group, the mRNA expression of ACE and AT1 receptor and protein expression of AT lI were noticeably higher than those in sham group [ACE mRNA was（3.15 ±0.13） vs （1.02 ±0.01）, （3.88 ±0.21） vs （1.05 ±0.02）, （4.16±0.12） vs （1.03 ±0.01）;AT1 mRNA was （1.53±0.23） vs （1.00±0.01）, （2.92±0.05） vs （1.06 ±0.03）, （3.62 ±0.03） vs （1.08 ±0.05）;Angllwas（10.55 ±0.24）μg,/L vs （3.00_± 0.12） μg/L, （7.43 ±0.23） μg/L vs （3.05 ±0.16） μg/L, （8.36 ±0.35） lxg/L vs （3.03 ±0.13） μg/L, P〈 0. 05 ]. Compared with PQ group, T group brought a remarkable down-regulation of mRNA and protein expression （ P 〈 0.05 ）. The scores of alveolitis and fibrosis and content of type I and III collagen in the tissue of lungs of T group on day 7 and day 14 were significantly less than those of PQ group. Conclusions State of activation of the local RAS may contribute to lung fibrosis induced by PQ poisoning. Benazepril can inhibit the proliferation of fibroblasts by suppressing local production of ACE and AT Ⅱ.