中文摘要：

本试验旨在研究低温诱发肉鸡腹水综合征（AS）过程中平滑肌细胞增殖在肺血管重塑过程中的动态变化，初步探讨肺血管重塑的机制。160只15日龄雄性AA商品代肉鸡随机分为对照组（22℃±1．5℃）和低温组（11℃±2℃）。试验持续至50日龄，期间每周每组随机取6只，取肺组织做石蜡切片，Weigert-间苯二酚复红染色，观察并测定血管重塑情况；采用免疫组织化学方法检测肺动脉增殖细胞核抗原（PCNA）蛋白表达，并对其半定量化，分析平滑肌细胞增殖情况。50日龄时统计整个饲养过程中AS发生率。结果显示：（1）低温组肉鸡AS发生率（18．75%）极显著高于对照组（1．25％）（P〈0．01）；（2）低温组肉鸡直径20～50μm和50～150μm肺动脉结构从36日龄开始较对照组发生了明显的重塑（P〈0．01或P〈0．05）；（3）低温组肉鸡直径20～50μm和50～150μm的肺动脉平滑肌细胞增殖指数分别从22日龄和36日龄开始极显著高于对照组（P〈0．01）。结果表明：低温诱发肉鸡AS过程中肺动脉结构发生了明显的重塑，肺动脉平滑肌细胞发生了明显的增殖，并且平滑肌细胞增殖促进了肺血管重塑，在肉鸡AS发生发展过程中起着重要的作用。

英文摘要：

Pulmonary vascular remodeling and proliferation of vascular smooth muscle cells （VSMCs） of pulmonary arteries of broilers in the development of ascites syndrome （AS） induced by low ambient temperature were dynamically analyzed to study the mechanism of pulmonary vascular remodeling. Broilers in control group （22 ℃±1.5℃） and low temperature group （11℃± 2 ℃） were sampled every week from 15 to 50 days of age. Mean medial thickness （mMTPA） and the ration of vessel wall area to vessel total area （WA ： TA）, the indexes of pulmonary vascular remodeling, were examined by computer-image analyzing system. Proliferative indexes （PI） of VSMCs in pulmonary arteries were assessed with proliferating cell nuclear antigen （PCNA）. The higher incidence （18.75%） of AS was induced, and pulmonary vascular remodeling were significantly elevated in low temperature group from 36 days of age （P〈0.05）. PI in pulmonary arteries with 20-50 μm and 50-150 μm diameter in low temperature group were significantly higher than those in the control group from 22 and 36 days of age separately（P〈0.05）. Our study demonstrated that VSMCs proliferated and pulmonary artery remodeled progressively in the development of AS, which suggest that proliferation of VSMCs facilitate pulmonary vascular remodeling and have a pivotal role in the development of AS in broilers.