1型血管紧张素Ⅱ受体拮抗剂对胰腺星状细胞的影响

Influences of angiotensinⅡtype 1 receptor antagonist on pancreatic steilate cells

目的探讨1型血管紧张素Ⅱ受体(AT_1)拮抗剂氯沙坦对胰腺星状细胞(PSC)的影响及其可能机制。方法①从胰腺癌患者胰腺组织中分离PSC并检测其AT_1的表达,用血管紧张素Ⅱ(AngⅡ)和氯沙坦干预后检测其Ⅰ型胶原的表达情况。②90只雄性SD大鼠均分为正常组、对照组和治疗组。后2组胰管内注射2%三硝基苯磺酸(TNBS)制成大鼠胰腺纤维化模型。治疗组给予氯沙坦灌胃,对照组给予等容积的无菌蒸馏水。于制模后第3、7、14、21和28天分别处死大鼠,留取胰腺组织。电镜下观察胰腺组织超微结构改变；应用逆转录-聚合酶链式反应(RT-PCR)检测胰腺组织转化生长因子β_1(TGFβ_1)、Ⅰ型前胶原mRNA表达；应用免疫组化法检测胰腺组织α-平滑肌肌动蛋白(α-SMA)和TGFβ_1蛋白表达；应用Western印迹法检测胰腺组织α-SMA动态表达水平。结果体外研究显示,AT_1表达于人胰腺癌组织PSC,氯沙坦可抑制其Ⅰ型胶原的表达。体内研究表明,氯沙坦可逆转胰腺纤维化大鼠电镜下胰腺细胞异常改变；胰腺纤维化大鼠胰腺组织α-SMA、TGFβ_1和Ⅰ型前胶原表达增加,氯沙坦可下调其表达。结论AT_1拮抗剂通过阻断AT_1途径抑制PSC活化及其促纤维化作用。

To investigate the effects of Losartan, an angiotensin Ⅱ （Ang Ⅱ ） receptor （AT1） antagonist, on pancreatic stellate cells （PSCs） and its possible mechanisms. Methods （1） PSCs were isolated from pancreatic cancerous samples to test the expressions of AT1 and collagen I after incubated with Ang Ⅱ or/and Losartan. （2）Ninety S-D rats were divided into normal group, control group and treatment group, with 30 rats in each. The rats in control and treatment groups were induced pancreatic fibrosis by injection of 2% trinitrobenenze sulfonic acid （TNBS） into biliopancreatic duct. Rats in treatment group were then treated with Losartan by garage daily and rats in control group were only given distilled water. The rats were sacrificed on day 3, 7, 14, 21 and 28, respectively, and pancreas were removed. The histological abnormalities were observed by electron microscope. The mRNAs of transforming growth factor β1 （TGFβ1） and procollagen Ⅰ were detected by reverse transcription-polymerase chain reaction （RT-PCR）. The expression of TGFβ1 and α-smooth muscle actin （α-SMA） proteins was assessed by immunohistochemistry and the level of α-SMA protein was quantified by Western blot. Results In vitro, there existed AT1 expression in PSCs, and Losartan reduced expression of collagen Ⅰ. Losartan treatment reversed the histological abnormalities observed by electron microscope, compared to treatment with distill water. The expression of α-SMA, TGFβ1 and procollagen Ⅰ were significantly higher in the control group than those in normal group and were reduced by Losartan to different extent in treatment group. Conclusion AT1 antagonist can inhibit the activation and the profibrogenic action of PSCs by blocking AT1 receptor-mediated pathways.