Expression Patterns of Aquaporins in the Cochlea and Endolymphatic Sac of Guinea Pig / 听力学及言语疾病杂志

ABSTRACT

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.