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目的肾素-血管紧张素系统(renin-angiotesin system,RAS)与肺纤维化的发生发展密切相关,文中拟观察RAS系统重要靶向轴血管紧张素转换酶(angiotensin converting enzyme,ACE)2-血管紧张素(angiotensin,Ang)(1-7)-Mas轴在动式染尘法矽肺大鼠模型中动态变化规律。方法实验分为对照组以及染尘2、4、8、16、24周组,每组10只。实验组采用HOPE-MED8050动式染尘控制系统构建大鼠矽肺模型,分别染尘2、4、8、16、24周。对照组未行染尘处理。采用HE、Masson染色观察病理形态;免疫组化染色检测α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)、波形蛋白(vimentin)、ACE2在肺组织中的定位和表达;Western blot法检测肺组织I型胶原、α-SMA、vimentin、ACE2和Mas的表达;ELISA检测肺组织中Ang(1-7)的含量。结果 HE、Masson染色结果显示染尘8周可出现细胞性矽结节,染尘16周可出现多个结节的融合,至染尘24周时可出现细胞纤维性结节。免疫组化染色结果显示,ACE2主要定位于支气管纤毛上皮细胞、肺泡上皮细胞,而在矽结节中ACE2表达明显减弱。Western blot结果显示,与对照组Ⅰ型胶原(0.05±0.01)、α-SMA(0.03±0.01)比较,染尘2、4、8、16、24周组Ⅰ型胶原(0.11±0.01,0.22±0.02,0.42±0.01,0.90±0.03,1.48±0.02)、α-SMA表达(0.08±0.01,0.17±0.02,0.28±0.01,0.43±0.01,0.42±0.01)均明显升高(P<0.05),染尘8、16、24周Vimentin表达明显升高(P<0.05)。与对照组比较,染尘4、8、16、24周组ACE2表达降低(P<0.05),染尘2、4、8、16、24周Mas表达降低(P<0.05)。ELISA法检测肺组织中Ang(1-7)含量结果显示,随着染尘时间的延长Ang(1-7)的表达逐渐降低。结论动式染尘能够构建矽肺大鼠模型,而ACE2-Ang(1-7)-Mas轴表达水平下调参与了矽肺大鼠纤维化的进展。
Objective Renin-angiotesin system (RAS) is closely related to the occurrence and development of pulmonary fibrosis. In this paper, it is to observe the important target axis of RAS system, angiotensin converting enzyme (ACE) 2-vessel The dynamic changes of angiotensin (Ang) (1-7) -Mas axis in the silicotic model of silicotic rats by dynamic dusting method. Methods The experiment was divided into control group and 2, 4, 8, 16, 24 weeks group, 10 in each group. Experimental group using HOPE-MED8050 dynamic dust control system to build rat silicosis model, respectively, dust 2,4,8,16,24 weeks. The control group did not handle the dust. The pathological changes were observed by HE and Masson staining. The expression and localization of α-smooth muscle actin (α-SMA), vimentin and ACE2 in lung tissue were detected by immunohistochemistry. Western blot The expressions of type I collagen, α-SMA, vimentin, ACE2 and Mas in lung tissue were detected by ELISA. The content of Ang (1-7) in lung tissue was detected by ELISA. Results The results of HE and Masson staining showed that the cell-like nodules could be seen after 8 weeks of infection, and multiple nodules could appear after 16 weeks of dust exposure. Immunohistochemical staining showed that ACE2 mainly localized in bronchial ciliated epithelial cells and alveolar epithelial cells, while ACE2 expression was significantly reduced in silicon nodules. Western blot results showed that compared with control group (0.05 ± 0.01) and α-SMA (0.03 ± 0.01), collagen typeⅠcollagen (0.11 ± 0.01,0.22 ± (P <0.05). The expression of α-SMA (0.08 ± 0.01,0.17 ± 0.02,0.28 ± 0.01,0.43 ± 0.01,0.42 ± 0.01) At 8, 16 and 24 weeks, the Vimentin expression was significantly increased (P <0.05). Compared with the control group, the expression of ACE2 decreased at 4, 8, 16, 24 weeks (P <0.05) and decreased at 2, 4, 8, 16, 24 weeks after exposure to dust (P <0.05). The level of Ang (1-7) in lung tissue was detected by ELISA. The results showed that the expression of Ang (1-7) decreased gradually with the increase of dusting time. Conclusions Dynamic dyed dust can construct silicotic rat model, while down-regulation of ACE2-Ang (1-7) -Mas axis is involved in the progression of fibrosis in silicotic rats.