NO治疗先心病合并重度肺动脉高压病理机理的研究

Vascular Smooth Muscle Cell Apoptosis in Lungs Induction by Nitric Oxide in Congenital Heart Disease and Pulmonary Hypertension

目的 对比三组肺小动脉平滑肌细胞凋亡状态,通过了解左向右分流型先心病合并重 度肺动脉高压的肺小动脉平滑肌细胞凋亡状态,进而了解NO肺动脉高压的病理改变及其发病机制。 方法选择先心病患儿15例,0．5-5(2．9±1．5)岁。组1为肺动脉增生吸入NO治疗组共6例,治 疗组包括室间隔缺损(VSD)2例和完全心内膜垫缺损(ECD)4例均合并重度肺动脉高压;组2为肺动 脉增生不吸NO对照组共3例,包括VSD 2例和ECD 1例均合并重度肺动脉高压;组3为肺动脉发育 不良组包括3例法鲁氏四联症(TOF)患儿;组4为正常肺动脉组包括3例房间隔缺损(ASD)+轻度 肺动脉瓣狭窄(PS)。采用TUNEL技术,HF染色及弹力染色等方法。结果 TUNEL染色结果表明, 肺动脉增生组的肺小动脉平滑肌细胞凋亡明显减弱,偶见平滑肌细胞凋亡;肺动脉发育不良组的肺小 动脉平滑肌细胞凋亡活跃;正常肺动脉组有细胞凋亡,但无增多。结论肺动脉增生,正常和发育不 良等三组先心病的肺小动脉平滑肌细胞凋亡状态不同,肺动脉增生组与正常肺动脉比较,左向右分流 型先心病合并重度肺动脉高压的肺小动脉平滑肌细胞凋亡相对减少,肺动脉发育不良组与正常肺动 脉比较,法鲁氏四联症的肺小动脉平滑肌细胞凋亡相对增多。

Objectives Cell apoptosis was assessed in congenital heart disease by NO treatment in order to explore the molecular biological mechanism of pulmonary hypertension. Methods Total of 15 patients with congenital heart disease were selected from March to July in 2001. there were 10 male patients and 5 female patients, with age ranged from 0.5 to 5 years old （mean 2.9±1.5 years old）. Patients were divided into 4 groups： Group 1 included 2 cases of ventricular septal defect and 4 cases of total atrioventricular canal defect with severe pulmonary hypertension. Patients in group 1 were treated with inhalation of 5～10 ppm NO and pure oxygen 2～4 hours a day for 10 to 14 days. Heart rate, blood pressure and oxygen saturation are monitored. Group 2 included 2 cases of ventricular septal defect and 1 case of atrioventricular canal defect with severe pulmonary hypertension without inhalation of NO before operation. Group 3 included 3 cases of Tetrology of Fallot. Group 4 included 3 cases of atrial septal defect without pulmonary hypertension. During the operation, a 0.5×0.5 cm^2 lung specimen was taken from the middle lobe of the right lung and was prepared to had HE stain, elastic stain, and TUNEL stain respectively. Results Groupl showed active apoptosis of smooth muscle cell in small artery after NO treatment before operation. Group 2 showed an obvious thickening of middle layer of the small artery and proliferation of elastic fiber and significant decrease of smooth muscle cell apoptosis. Group 3 showed no thickening of smooth muscle cell in small artery and no increase of cell apoptosis. Group 4 showed thinning and dilation of smooth muscle cell wall in small artery, no obvious elastic fiber and active apoptosis of smooth muscle cell in small artery. We proved that apoptosis of smooth muscle cell is decreased in patients with pulmonary hypertension but increased in patients with Tetrology of Fallot. Research of secondary pulmonary hypertension indicated that due to unbalance of cell proliferation and apoptosis caused by increase of cell proliferation, accumulation of cells would lead to pulmonary vascular remodeling. Conclusions Our study indicated that pulmonary hypertension may relate with decrease of smooth muscle cell apoptosis in molecular biological level. We speculated that NO can increase cell apoptosis and inhibits endothelial cell and smooth muscle cell over proliferation, thus inhibits pulmonary vascular remodeling.