慢性缺氧性肺动脉高压大鼠肺血管显微结构研究

目的 观察大鼠在慢性低氧环境中不同节段肺血管显微结构的变化规律，探讨其在慢性缺氧性肺动脉高压形成中的病理意义。方法 将23只Wistar大鼠随机分为对照组、低氧1周组、低氧2周组。以右心导管法测定肺动脉压力；对肺组织进行弹力纤维染色，计数各型肺内动脉百分比；应用计算机图像分析系统测定分别与三级呼吸道伴行的肺动脉的相对中膜面积（RMA）、厚度（RMT）及血管壁内弹力层（IEL）厚度。结果 低氧2周组大鼠肺动脉平均压明显高于对照组及低氧1周组，低氧1周组肺动脉平均压明显高于对照组；低氧2周组肌型动脉百分比（MA％）、三组动脉RMA、RMT均明显高于对照组及低氧1周组，低氧1周组MA％、肺泡水平动脉RMA、RMT明显高于对照组（P均＜0．05）。与对照线相比，低氧2周组和1周组肺内动脉血管壁IEL均明显减少（P均＜0．05）。多因素相关分析表明，肺动脉平均压与肺泡水平动脉RMA、RMT呈正相关；与肺泡水平肺动脉血管壁IEL厚度呈负相关（P均＜0．05）。结论 慢性低氧环境中大鼠肺血管结构呈现节段依赖性的重构规律，这一改变是缺氧性肺动脉高压形成的重要病理基础。

Pulmcnary vascular microstructure in chronic hypoxic pulmonary hypertension

Objective To explore the regularity of hypoxic pulmonary hypertension with microstructural changes in the diffe rent segments of intrapulmonary arteries.Methods Twenty three Wistar rats age and weight matched, were randomly divided into one week hypoxic group, two week hypoxic group and the control group. Pulmonary artery mean pressure mPAP) of each rat was evaluated using right cardiac catheterization . Lung tissues were dyed with Weigherts method. The percentage of each type of intra acinar pulmonary arteries was measured.Relative media thickness (RMT) and relative media area (RMA) of the intrapulmonary arteries accompanying with three segments of air way respectively were observed with a Computer Image Analysis System.Results mPAP significantly increased in two week hypoxic group as compared with that of one week hypoxic group and normal controls .And mPAP in one week hypoxic group markedly increased compared with that of normal controls (P<0.05). The percentage of muscularized artery ,RMA and RMT of three segments of pulmonary arteries significantly increased in two week hypoxic group as compared with that of one week hypoxic group and normal controls,and the percentage of muscularized artery, RMT and RMT of pulmonary arteries at the level of alveoli in one week hypoxic group markedly increased compared with normal controls (P<0.05). Compared with control group ,the thickness of internal elastic layer (IEL) in rats of two week hypoxic and two week hypoxic group reduced(P< 0.05). mPAP was positively correalated with RMA and RMT of pulmonary arteries at the level of alveoli,and negatively correlated with the thickness of IEL of pulmonary arteries at the level of alveoli.Conclusion Segement dependent pulmonary vascular structural remodeling is of great importance in the pathological process of hypoxic pulmonary hypertension.