早产新生大鼠高氧肺损伤Shh信号转导途径Smo和Gli1蛋白表达和意义

To study the role of Smo and Gli1 expression in Sonic hedgehog signaling pathway in hyperoxia-induced lung injury of premature rats

目的探讨高氧诱导新生大鼠急性肺损伤中Shh信号通路Smo和Gli1蛋白的表达及其意义。方法建立早产新生大鼠高氧肺损伤模型。实验组持续吸入氧体积分数大于95%的医用氧气,对照组吸入空气。分别留取第3、7、14天的肺组织,肺组织切片HE染色观察肺脏病理改变,应用Western blot技术检测肺组织Smo和Gli1蛋白的动态表达情况。结果实验组高氧暴露3天肺毛细血管开始充血、渗出;7天肺结构紊乱,炎性细胞浸润;14天肺泡融合,纤维增生,间隔增宽。实验组Smo和Gli1蛋白主要分布于支气管上皮、肺泡上皮细胞、血管内皮细胞及部分纤维组织。与对照组相比,实验组高氧第7天Smo蛋白表达显著增加[(0.423±0.056)比(0.061±0.008)],14天达高峰[(0.612±0.082)比(0.132±0.011)];Gli1蛋白于14天表达显著增加[(0.515±0.071)比(0.209±0.013)],P均<0.05。结论高氧可致新生大鼠肺泡结构紊乱和肺发育停滞,Smo和Gli1蛋白呈现高表达,这可能和高氧诱导的肺损伤和支气管肺发育不良的发生发展有关。

Objective To study the expressions of Smo and Glil in lungs of newborn rats exposed to prolonged hyperoxia and look at the role of Sonic hedgehog （Shh） signaling pathway in hyperoxia-induced lung injury. Methods Neonatal rat pups were placed in chambers containing room air or oxygen ≥95% for 14 days after birth. The rats were sacrificed at 3, 7 or 14-day and their lungs removed and subjected to hematoxylin and eosin（HE） staining. The dynamic expressions of Smo and Glil protein were assessed using Western blotting. Results Significant histo-morphologic changes were shown in the hyperoxia-exposed lungs at 3, 7 and 14-day of age. Smo and Glil proteins were observed in bronchial epithelial cells, alveolar epithelial cells ,vascular endothelium cells, and part of fibrotic tissue in lung interstitium. Western blot showed that the expression of Smo was significantly higher in the hyperoxia-exposed lungs at 7 [ （0. 423 ± 0. 056） vs. （0. 061 ±0. 008 ） ] and 14-day [ （0. 612 ± 0. 082） vs. （0. 132 ±0.011 ）] ,and Glil was significantly elevated at 14-day [ （0. 515 ±0.071 ）vs. （0. 209 ± 0. 013） ]. But low Smo and Glil were detected in room air group. Conclusions Exposure of neonatal rat to prolonged hyperoxia results in acute lung injury up-regulated at time points preceding the lung injury, the pathogenesis of hyperoxia-induced lung injury and and arrested lung development. Smo and Glil are and Shh signal pathway are probably involved in bronchopulmonary dysplasia.