大鼠耳蜗组织中Nedd4及SGK1的表达

Expression Patterns of Nedd4 Isoforms and SGK1 in the Rat Cochlea

目的研究大鼠耳蜗组织中神经前体细胞表达-发育性下调基因亚型(neural precursor cell-ex-pressed,developmentally downregulated isoforms,Nedd4)及血清糖皮质激素诱导激酶1(serum glucocorticoid-in-ducible kinase1,SGK1)蛋白分子的表达。方法选取健康Wistar大鼠8只,用特异性多克隆兔抗鼠Nedd4-1/2、Nedd4-2及SGK1抗体,采用免疫组化法研究大鼠耳蜗组织中Nedd4-1/2、Nedd4-2及SGK1蛋白的表达模式。结果Nedd4-1/2、Nedd4-2及SGK1蛋白广泛表达于大鼠耳蜗组织的各个区域中,包括血管纹、螺旋韧带、Corti器、螺旋缘、螺旋神经节、前庭膜等处。结论在耳蜗组织中,存在一个由SGK1、Nedd4和上皮钠通道(ENaC)组成的Na+转运系统,它们协同作用转运Na+,从而保持内耳内环境的稳定。

Objective To investigate the cellular localization of the neural precursor cell-expressed,developmentally downregulated isoforms（Nedd4）,Nedd4-1/2 and Nedd4-2,and the serum glucocorticoid-inducible kinase1（SGK1） in various subregions of the rat cochlea.Methods The expression patterns of Nedd4-1/2,Nedd4-2 and SGK1 in the cochlea of rat were studied by immunohistochemistry with the specific polyclonal rabbit antibodies against the rat Nedd4-1/2,Nedd4-2 and SGK1.Results All three proteins were extensively expressed in various regions of the rat cochlea.They were found in the stria vascularis,spiral ligament,organ of Corti,spiral limbus,spiral ganglion and Reissner＇s membrane.Conclusion Our findings suggest that there exists a Na＋ transport system in the cochlea consisting of SGK1,Nedd4 isoforms and ENaC,which may work in concert to transport Na^＋ and to maintain homeostasis in the inner ear as they do in other tight epithelia.