大鼠缺氧肺动脉高压模型肺组织信号转导与转录激活因子的表达

Enhanced expression of signal transducers and activators of transcription in lung tissue of hypoxic pulmonary hypertension rat models

目的 通过观察大鼠常压缺氧肺动脉高压模型肺组织信号传导与转录活化因子(STATs)的表达水平 ,探讨其在低氧性肺动脉高压 (HPH)形成过程中参与的可能机制。方法 健康成年雄性Wistar大鼠 6 0只 ,随机分为缺氧组和健康对照组 ,缺氧组大鼠复制HPH模型。用逆转录 (RT) 聚合酶链反应 (PCR)和Northernblot检测 2组大鼠肺组织STATsmRNA的表达水平 ,免疫组化检测大鼠肺组织STATs蛋白的含量。结果 RT PCR扩增显示 ,缺氧 1周大鼠肺组织STAT 1、STAT 2、STAT 3、STAT5mRNA表达水平升高 ,缺氧 2周表达水平最高 ,缺氧 3周表达水平降低 ,但明显高于健康对照组 ;且缺氧 2周的表达水平高于其他缺氧时间 (P <0 0 5 ) ;STAT 4未检出。Northernblot显示 ,缺氧 2周大鼠肺组织STAT 1、STAT 3、STAT 5mRNA表达高于其他缺氧时间 (P <0 0 1)。缺氧 3周大鼠肺组织STAT3和STAT 5组化染色可见 ,肺泡壁细胞、支气管壁细胞、小血管壁细胞及巨噬细胞的胞核呈紫蓝色 ;图像定量分析显示 ,缺氧 3周大鼠肺组织STAT 3和STAT 5蛋白表达含量最高 ,缺氧 4周含量降低 ,但仍高于健康对照组 (P <0 0 1)。结论 大鼠常压缺氧肺动脉高压模型肺组织STATsmRNA和蛋白表达增高 ,提示STAT可能参与了HPH的发病机制。

Objective To investigate the expression levels of signal transducers and activators of transcription(STATs) in the lung tissue of hypoxic pulmonary hypertension (HPH) rat models. Methods The Wister rat HPH models were divided into 4 groups: 1 week group (H1), 2 week group (H3), 3 week group (H3),and 4 week group (H4) (n =12 in each group). The levels of STATsmRNA expression of the lung tissue were measured by reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot. The protein expression of STATs and cellular morphologic changes were observed by immunohistochemistry and Tiger image analysis. Results The RT-PCR showed that the levels of STAT1mRNA expression of the lung tissue in H1 1.25±0.12, H2 2.28±0.15 and H3 1.27±0.12 were significantly higher than that in the healthy control group 0.61±0.07(P<0.01); the levels of STAT2mRNA expression in H1 0.54±0.06, H2 1.01±0.08 and H3 1.36±0.09 were significantly higher than that in control group 0.30±0.03(P<0.01); the mRNA expressions of STAT3 in H1 0.74±0.11, H2 1.19±0.13 and H3 0.80±0.08 were significantly higher than that in control group 0.26±0.10(P<0.01); and the mRNA expressions of STAT5 in H1 0.92±0.10, H2 1.23±0.10 and H3 1.03±0.11 were significantly higher than that in control group 0.60±0.11(P<0.01).The Northern blot assay demonstrated that the expressions of STAT1mRNA in H1 0.49±0.10 and H3 0.67±0.07 were significantly different from that in H2 0.91±0.07(P<0.01); the expressions of STAT3mRNA in H1 2.10±0.21 and H3 2.58±0.17 were significantly different from that in H1 3.56±0.29(P<0.01); the expressions of STAT5mRNA in H1 0.99±0.10 and H3 1.45±0.12 were significantly different from that in H2 1.79±0.15(P<0.01). It is obvious that the mRNA expressions of STATs in the lung tissue of rat HPH models were increased in the 1st week, to the highest in the 2nd week, and decreased in the 3st week, and all higher than that of control group. The granules of STAT3 and STAT5, positively stained, were observed in the cytoplasm of pulmonary alveolar wall, intrapulmonary vascular and bronchial wall in H3. The protein expressions of STAT3 8.16±0.49 and STAT5 6.03±0.37 in H3 were markedly higher than those in H1,H4,and control group. Conclusion The up-regulation of the STATs expression in lung tissue of HPH rat models suggested that the STATs were involved in the pathogenesis of HPH formation.