摘要
OBJECTIVE: To determine if aquaporin1 (AQP1) and aquaporin5 (AQP5) are expressed in the alveolar capillary membrane in rats. Moreover, to investigate the alteration of AQP1 and AQP5 in acute injured lungs. METHODS: The distribution of AQP1 and AQP5 in alveolar capillary membrane were investigated by immunohistochemistry and immunoelectron microscopy with affinity-purified antibodies to human AQP1 and AQP5. To study the possibility that alveolar capillary membrane AQP1 and AQP5 undergo altered regulation, we established a rat model using alveolar instillation of lipopolysaccharide (LPS). RESULTS: Immunolabelling showed AQP1 was stained primarily in the microvascular endotheli a of normal lungs, while AQP5 was expressed in type I pneumocytes. Immunohisto chemical analysis showed a significant decrease in the expression of AQP1 and AQP5 in injured lungs at 4h-48h after LPS instillation. AQP1 protein was resumed partly at 24h after LPS instillation and steroid administration, whereas AQP5 was unchanged. CONCLUSION: The decreased expressions of AQP1 and AQP5 in injured lungs suggest that both of them may play a role in abnormal fluid transportation.
水通道蛋白是一组水选择通道的分子家族 ,它们都有增加浆膜面水通透力的功能 ,因而可以提供快速液体转运的通路。本实验的目的是确定AQP1及AQP5是否在大鼠肺泡毛细血管膜 (呼吸膜 )表达 ,进而研究内毒素诱导的急性肺损伤 (ALI)大鼠AQP1和AQP5的表达调节及激素干预的作用。方法 采用亲和的抗人AQP1和AQP5抗体 ,应用免疫组化及免疫电镜的方法研究AQP1及AQP5在呼吸膜的分布。选用肺泡内灌注脂多糖 (LPS)制作大鼠ALI动物模型 ,研究ALI时呼吸膜AQP1及AQP5的变化。结果 免疫染色显示AQP1主要表达于正常肺组织的微血管内皮 ,而AQP5主要表达于肺泡I型上皮细胞。免疫组化分析进一步表明LPS灌注后 4h - 48hAQP1及AQP5在呼吸膜的表达均下降 ;AQP1蛋白于LPS灌注后 2 4h及激素干预后有部分恢复 (P <0 0 5 ) ,而AQP5无这种恢复现象。结论 本研究显示ALI时AQP1及AQP5在呼吸膜的表达减少 ,提示ALI时AQP1和AQP5的下降表达可能与其液体转运的异常有关。
基金
ThisprojectwassupportedbytheNationalNaturalScienceFoundationofChina (No 3 9870 3 3 8)
