RhoA/ROCK信号通路在左心疾病致大鼠肺动脉高压模型中的作用

目的 探讨RhoA/ROCK信号通路在左心疾病相关的大鼠肺动脉高压模型中的表达水平和作用。 方法 3-4周龄健康雄性SD大鼠20只，体重90-100g，随机分为对照组（C组：n=10）、肺高压组（H组：n=10）。H组采用升主动脉固定缩窄术建造左心疾病相关肺动脉高压大鼠模型，C组大鼠行假手术处理（钛夹固定于血管旁纵隔组织而非升主动脉，其他所有手术操作同H组），在建模后60天，对各组大鼠进行血流动力学（右心室收缩压、肺动脉压力）检测，处死大鼠并用PBS行在体心肺灌洗致双肺变白，左肺组织固定于4%多聚甲醛行病理切片以观察肺组织病理形态学变化、右肺组织冻存以备生物分子学检测（Rho激酶mRNA、RhoA mRNA、ET-A 受体mRNA）。结果 与C组相比，H组肺动脉压力、右心室收缩压明显增高(P<0.01)，肺小动脉壁明显增厚，肺小动脉管腔狭窄甚至闭塞，管壁肥厚指数明显增大（P<0.01）；与C组相比，H组肺组织的Rho激酶mRNA表达水平明显增加，RhoA mRNA、ET-A 受体mRNA表达水平亦明显增加，差异均有统计学意义（P<0.01）。结论 采用升主动脉固定缩窄术成功建造了左心疾病相关肺动脉高压大鼠模型；与C组相比，H组肺小血管壁明显增厚，肺组织的Rho激酶mRNA、RhoA mRNA、ET-A受体 mRNA表达明显增高，该信号通路可能参与了左心疾病相关肺动脉高压的形成过程。

The role of RhoA/ROCK pathway in the rat models of left heart disease-associated pulmonary hypertension

Objective To investigate the role of RhoA/Rho-kinase pathway in rat models of left heart disease-associated pulmonary hypertension (PH-LHD).Methods Twenty male SD rats (3-4 week-old, 90-100 g) were randomly divided into two groups (10 rats in each group):the group C (control group) with sham operation, and group H (pulmonary arterial hypertension). The rat model of left heart disease-associated pulmonary hypertension was established by supracoronary aortic banding in the group H, and the sham surgery was applied for the rats in the group C (The titanium clip was fixed at the mediastinal tissue adjacent to the artery rather than the ascending aorta). On day 60 after the operation, the cardiac functions, including right ventricular systolic pressure and pulmonary artery pressure were evaluated. After that, all rats were sacrificed and treated with cardiopulmonary lavage in vivo until the lung became white. Then the left lung tissues were fixed in 4% paraformaldehyde for pathological observation while the right lung tissues were frozen for mRNA detection. Results Compared with the group C, both ventricular systolic pressure and pulmonary artery pressure in the group H were increased significantly (P<0.01). Pathological data demonstrated that the pulmonary artery walls in H group were much thicker than that in the group C. Moreover, vascular wall hypertrophy index in the group H was increased greatly compared with that in the group C (P<0.01). QPCR data showed that mRNA levels of Rho kinase, RhoA and ET-A R in the group H were up-regulated compared with the group C (P<0.01). Conclusions Rat model of left heart disease-associated pulmonary arterial hypertension can be successfully established by supracoronary aortic banding. Rho-kinase-mediated pathway may contribute to the pathogenesis and progress of left heart disease-associated pulmonary arterial hypertension.