水通道蛋白在正常豚鼠中耳腔的表达及作用

Expression and its role of aquaporin in the middle ear of the guinea pigs

目的观察水通道蛋白(aquaporins,AQP)1、AQP4、AQP5在正常豚鼠中耳腔黏膜的表达和分布情况,探讨AQP1、AQP4、AQP5在豚鼠中耳液体转运和水平衡中的作用机制。方法用逆转录聚合酶链反应、免疫印迹和免疫组织化学的方法观察正常豚鼠中耳腔黏膜AQP1、AQP4、AQP5的表达和分布情况。结果AQP1、AQP4、AQP5的mRNA在正常豚鼠中耳腔黏膜内有确定表达,AQP1、AQP4蛋白在正常豚鼠中耳黏膜内有确定表达,中耳腔的扁平上皮、立方上皮、黏膜下层的毛细血管内皮和此层的纤维母细胞的胞浆中均有AQP1分布。结论AQP1、AQP4、AQP5共同参与中耳腔的液体平衡过程,保持中耳腔正常情况下的无液体积聚状态。

OBJECTIVE To explore the expression pattern of AQP1, AQP4, AQP5 in the normal middle ear in guinea pigs and its roles in the water homeostasis in the middle ear cavity. METHODS Reverse transcription polymerase chain reaction （RTPCR）, Western blotting and immunohistochemical staining were used to detect AQP1, AQP4, AQP5 in mucosa of the bullae of normal guinea pigs. RESULTS Reverse transcription-polymerase chain reaction and immunoblot analyses revealed that mRNAs encoding AQP1, AQP4, AQP5 were expressed in middle ear membrane of the guinea pigs. AQP1, AQP4 was also detected as 28-kDa, 33-kDa proteins in middle ear cavity of guinea pig. Immunohistochemical staining showed that only AQP1 located at capillary endothelial cells and fibroblasts of the submucous layer, as well as at flat and cubical epithelial cells. CONCLUSION The results suggest that AQP1, AQP4, AQP5 can express in the normal middle ear cavity of guinea pigs and may play a vital role in the water transmission in the middle ear. The air-filled middle ear cavity may result from the working of AQP1, AQP4, AQP5.