豚鼠耳蜗和内淋巴囊水通道蛋白的表达

目的 研究豚鼠耳蜗和内淋巴囊组织中水通道蛋白(aquaporin，AQP)不同亚型的定位表达及其意义。方法 用兔抗大鼠AQP1、AQP2、AQP3、AQP4的多克隆抗体，采用免疫组化SP法分别检测相应AQP蛋白亚型在豚鼠耳蜗和内淋巴囊组织中的表达模式。结果 在耳蜗组织中，AQP1、4广泛分布于耳蜗的各个区域，如血管纹、螺旋韧带、Corti器、螺旋缘、螺旋神经节等，AQP3除了在血管纹表达呈弱阳性外，其余区域的表达与AQP1和AQP4相似，AQP2则仅表达于Reissner膜。在内淋巴囊组织中，AQP1、AQP3和AQP4在内淋巴囊上皮细胞和上皮下纤维组织均呈强阳性表达，只是AQP3的表达强度稍弱于AQP1和AQP4，而AQP2在内淋巴囊上皮细胞和上皮下组织均呈阴性表达。结论 水通道蛋白1、3、4以相似的方式广泛分布于豚鼠耳蜗和内淋巴囊组织中，而AQP2则仅表达于Reissner膜，提示不同亚型的AQP可能在不同区域协同作用参与内淋巴的调节，从而保持内耳内环境的稳定。

Expression Patterns of Aquaporins in the Cochlea and Endolymphatic Sac of Guinea Pig

Objective To investigate the cellular localization of aquaporins(AQPs) and its significance in various subregions of the cochlea and endolymphatic sac of guinea pig.Methods Adult guinea pigs were used and the expression patterns of AQP1,2,3 and 4 in the cochlea and endolymphatic sac were studied immunocytochemically. Paraffin- embedded sections were labeled with the specific polyclonal rabbit antibodies against the rat AQP1, 2, 3, and 4.Results In the cochlea, AQP1, 3, 4 were widely distributed in various subregions including the stria vascularis, spiral ligament, organ of Corti and spiral ganglion in the similar patterns except that AQP3 in the stria vascularis was weaker than AQP1 and AQP4. AQP2 was labeled only in the Reissner's membrane. In the endolymphatic sac, AQP1, AQP3 and AQP4 were strongly expressed in the epithelial cells and subepithelial cells with the exception that AQP3 was a little weaker than AQP1 and AQP4. No AQP2 immunoreactivity was detected in the endolymphatic sac.Conclusion Our immunohistochemical results suggest that different members of AQPs family in labyrinth may work in concert to regulate endolymph and to maintain homeostasis in the inner ear.