硫化氢对大鼠高肺血流性肺血管重构机制影响的研究

目的 探讨硫化氢（hydrogen sulfide,H2S）对大鼠高肺血流性肺血管重构的影响及其机制。方法 雄性SD大鼠32只,随机分为分流组、分流＋硫氢化钠（sodiumhydrosulfide,NaHS）组、对照组和对照＋NaHS组。分流组和分流＋NaHS组大鼠经腹主动脉一下腔静脉穿刺建立高肺血流动物模型。用敏感硫电极法测定大鼠肺组织H2S含量;计算大鼠肺肌型动脉（muscularized artery,MA）的百分比及MA的相对中膜厚度（relativemedialthickness,RMT）;应用蛋白质免疫印迹技术（Westernblot）定量分析大鼠肺动脉平滑肌细胞增殖细胞核抗原（proliferation cell nuclear antigen．PCNA）、细胞外信号调节激酶（extracellular signal-regulated kinase,ERKl）、磷酸化细胞外信号调节激酶（phosphorylation extracellular signal-regulated kinase,P-ERK）;应用免疫组织化学法对PCNA进行定位及半定量分析。结果 分流11周后,与对照组比较,分流组大鼠肺组织H2S含量降低（P〈0．05）、肺动脉MA百分比及RMT升高（P〈0．05）;肺动脉PCNA阳性百分比、P-ERK／ERK1增高（P均〈0．01）。与分流组比较,分流＋NaHS组MA百分比及RMT低于分流组（P〈0．01）;肺动脉PCNA阳性百分比、肺动脉P-ERK／ERK1低于分流组（P〈0．01）。结论 H2S通过丝裂原活化蛋白激酶（mitogen-activated protein kinase,MAPK）／ERK信号转导通路调节大鼠高肺血流性肺血管重构。

Mechanism by which hydrogen sulfide regulates pulmonary vascular structural remodeling induced by high pulmonary blood flow in rats

OBJECTIVE: Pulmonary hypertension (PH) is a common complication of congenital heart defects with a left-to-right shunt characterized by high pulmonary blood flow. Pulmonary vascular structural remodeling (PVSR) is the pathological basis of PH. However, the pathophysiologic features and mechanisms responsible for PH and PVSR induced by increased pulmonary blood flow have not been fully understood. The present study was designed to explore the possible effect and mechanism of hydrogen sulfide (H(2)S) on the regulation of PVSR induced by high pulmonary flow in rats. METHODS: Thirty-two male SD rats, weighing 120 - 140 g, were randomly divided into shunt group (n = 8), shunt + NaHS group (n = 8), control group (n = 8) and control + NaHS group (n = 8). Rats in shunt group and shunt + NaHS group were subjected to an abdominal aorta-inferior vena cava shunt to create an animal model of high pulmonary flow. Rats in the control and control + NaHS groups underwent the same experimental protocol as mentioned above except for the shunt procedure. Rats in the shunt + NaHS and control + NaHS groups were intraperitoneally injected with NaHS at 56 micromol/(kgxd), and rats in the shunt and control groups were injected with the same volume of physiological saline. After 11 weeks of experiment, rats were sacrificed and lung tissues were obtained. The percentage of muscularized artery (MA) was calculated. The changes in relative medial thickness (RMT) in small pulmonary arteries and median pulmonary arteries were examined. Proliferative cell nuclear antigen (PCNA), extracellular signal-regulated kinase (ERK1) and phosphorylation extracellular signal-regulated kinase (P-ERK1) protein expression were examined by Western blot, and at the same time, PCNA protein expression by pulmonary artery smooth muscle cells was observed by immunohistochemistry. RESULTS: After 11 weeks of shunt, compared with control group, the percentage of MA increased significantly (25.12 +/- 2.26 vs 14.42 +/- 3.41, P < 0.05), and RMT in small pulmonary arteries and median pulmonary arteries increased significantly in rats of shunt group (23.6 +/- 3.5 vs 12.6 +/- 2.1, 24.8 +/- 1.9 vs 13.5 +/- 2.2, P < 0.05 for all). PCNA protein expression in small and median pulmonary arteries increased significantly (0.49 +/- 0.04 vs 0.39 +/- 0.07, 0.46 +/- 0.08 vs 0.36 +/- 0.05, P < 0.01 for all), and the ratio of PERK/ERK1 protein expression of pulmonary arteries increased significantly (P < 0.01) in rats of shunt group compared with those of control group. After the administration of exogenous H(2)S donor, NaHS, for 11 weeks, in contrast to rats in shunt group, the percentage of MA decreased significantly (21.5 +/- 2.0 vs 25.1 +/- 2.3, P < 0.05), and RMT in small and median pulmonary arteries decreased significantly (20.2 +/- 2.8 vs 23.6 +/- 3.5, 20.8 +/- 3.1 vs 20.8 +/- 3.1, P < 0.05 for all) in rats of shunt + NaHS group. PCNA protein expression in small and median pulmonary artery smooth muscle cells decreased significantly (0.32 +/- 0.06 vs 0.49 +/- 0.04, 0.29 +/- 0.07 vs 0.46 +/- 0.08, P < 0.01 for all), and the ratio of PERK/ERK1 protein expression of pulmonary arteries decreased significantly (P < 0.01) in rats of shunt + NaHS group compared with that of shunt group. CONCLUSION: H(2)S may play a regulatory role in pulmonary vascular structural remodeling induced by high pulmonary blood flow via mitogen-activated protein kinase (MAPK)/ERK signal transduction pathway.