培哚普利和氯沙坦抗实验性肺纤维化的实验研究

目的 探讨血管紧张素转化酶抑制剂(ACEI)-培哚普利和血管紧张素Ⅱ 1型受体(AT-1受体)阻滞剂-氯沙坦对实验性肺纤维化的影响及其作用机制.方法 雄性Wistar大鼠24只,体质量250～280 g,分为以下4组.模型组:平阳霉素5 mg·kg1一次性气管内注入诱导肺纤维化;氯沙坦治疗组:氯沙坦10 mg·kg-1灌胃,每日1次;培哚普利治疗组:培哚普利2 mg.kg-1灌胃,每日1次;对照组:生理盐水气管内注入.第4周取材,Masson三i色染色检测大鼠肺组织学改变:用氯氨T法测定肺组织羟脯氨酸含量;免疫蛋白质印迹法检测AT-1受体、TGF-β1蛋白的表达;电泳迁移率变更分析(EMSA)检测肺组织NF-κB的活性;免疫蛋白质印迹检测IκBα的表达;明胶酶法测定金属蛋白酶-2,9的活性.结果 培哚普利组和氯沙坦组大鼠肺纤维化分级和肺组织羟脯氨酸含量低于模型组;培哚普利组AT-1受体蛋白质表达水平低于模型组和氯沙坦组,高于对照组(P<0.05);氯沙坦组AT-1受体蛋白质表达水平与模型组没有明显差异(P>0.05).培哚普利组和氯沙坦组TGF-β1蛋白质的表达低于模型组(P<0.05);培哚普利组、氯沙坦组NF-κB的活性与对照组相比无显著差异(P>0.05);模型组NF-κB的活性高于对照组、培哚普利组和氯沙坦组(P＞0.01).对照组、培哚普利组和氯沙坦组IkB的表达高于模型组(P＜0.01);培哚普利组和氯沙坦组IkB的表达与对照组相比无显著差异(p＞0.05).与对照组相比.培哚普利组、氯沙坦组和模型组金属蛋白酶-2,9活性增强(P<0.05);模型组金属蛋白酶-2,9活性高于培哚普利组和氯沙坦组(P<0.01).结论 培哚普利和氯沙坦可能通过抑制肺组织TGF-β1的表达以及NF-κB和金属蛋白酶-2,9的活性.从而发挥抗肺纤维化作用.

Perindopril and losartan attenuate bleomycin A5-induced pulmonary fibrosis in rats

OBJECTIVE: To evaluate the effects of angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 receptor (AT-1 receptor) blocker on the progression of rat pulmonary fibrosis induced by bleomycin A5. METHODS: Twenty-four male Wistar rats were randomized into pulmonary fibrosis model, perindopril treatment, losartan treatment and control groups. In the former 3 groups, pulmonary fibrosis was induced via intratracheal injection of bleomycin A5 (5 mg/kg), after which the rats in the perindopril and losartan groups received intragastric administration of the corresponding agents at the daily dose of 2 mg/kg and 10 m/kg, respectively. The rats in the control group had intratracheal injection of normal saline only. In the 4th week, the histological changes of the lung tissues were examined microscopically with Masson staining. Hydroxyproline content in the lungs was measured, and the protein expressions of AT-1 receptor, TGF-beta1 and IkappaBalpha were examined using Western blotting. DNA binding activity of NF-kappaB was analyzed with electrophoretic gel mobility shift assay (EMSA), and zymography was used to assess the activity of matrix metalloproteinase-2 and 9 (MMP-2, 9). RESULTS: Both perindopril and losartan treatment significantly reduced the pulmonary fibrosis score, content of hydroxyproline, protein expression of TGF-beta1, DNA binding activity of NF-kappaB and MMP-2, 9 activity, and increased cytoplasmic protein expression of IkappaBalpha. Perindopril treatment lowered the protein level of AT-1 receptor. CONCLUSION: Perindopril and losartan may inhibit bleomycin A5-induced pulmonary fibrosis in rats by reducing the protein expression of TGF-beta1 and suppressing the DNA binding activity of NF-kappaB and MMP-2, 9 activity.