Rho激酶在缺氧性肺动脉平滑肌细胞增殖中的作用

目的 研究低氧条件下Rho激酶是否参与低氧引起的血管平滑肌细胞增生。方法 组织块法培养大鼠肺动脉平滑肌细胞（PASMCs）。应用甲基噻唑基四唑（MTT）比色法观察细胞增生情况；流式细胞仪观察细胞周期的变化；蛋白质免疫印迹法（Western blot）检测Rho激酶的表达。结果 缺氧组MTT比色吸光度（A）值显著高于常氧组．缺氧24h＋Rho激酶抑制剂Y27632组A值显著低于缺氧24h组；缺氧组细胞周期G2／M期细胞比例显著高于常氧24h组，缺氧24h＋Y27632组细胞比例显著低于缺氧24h组。Western blot结果表明各缺氧组Rho激酶表达均明显高于常氧组，其中以缺氧24h组表达增高最明显；Rho激酶在缺氧24h＋Y27632组明显低于缺氧24h组。结论 缺氧可诱导PASMCs增殖，缺氧诱导的增生PASMCs中Rho激酶活性水平增加，提示缺氧致PASMCs增殖过程中Rho激酶可能发挥重要作用。

Effect of Rho kinase on hypoxia stimulated proliferation of pulmonary arterial smooth muscle cells

OBJECTIVE: To study whether Rho kinase is involved in the proliferation of pulmonary arterial smooth muscle cells (PASMCs) induced by hypoxia. METHODS: Rat's PASMCs were isolated and cultured. Methyl thiazolyl tetrazolium (MTT) was used to determine the growth of cells. The cell cycle was analyzed by flow cytometry. Western blot was used to assess the expression of Rho kinase. RESULTS: The results of MTT showed that the number of PASMCs was increased after exposure to low oxygen tension for 12 hours compared with PASMCs in normoxia. After exposure of PASMCs to hypoxia for 24 hours,the cellular proliferation peaked,and was higher than that of PASMCs exposed to normal oxygen tension, hypoxia and Y27632 (Rho kinase inhibitor) groups,then it declined when exposed for 48 hours. Analysis of cell cycle indicated that the ability of cell proliferation increased significantly in PASMCs exposed to hypoxia compared with normoxia. Rho kinase level was higher in PASMCs exposed to hypoxia compared with normoxia. CONCLUSION: Hypoxia stimulates proliferation of PASMCs and promotes PASMCs into the phase of mitosis. The expression of Rho kinase is increased in PASMCs that are exposed to hypoxia, and it shows that Rho kinase is activated by hypoxia in PASMCs. Rho kinase maybe involve in the proliferation of PASMCs induced by hypoxia.