正常和膜迷路积水豚鼠内耳水通道蛋白的表达及意义

Expression of Aquaporins in the Inner Ear of Normal Guinea Pigs and Guinea Pigs with Endolymphatic Hydrops

目的检测正常和膜迷路积水豚鼠内耳水通道蛋白(aquaporins,AQPs)的表达,探讨其机理和意义。方法 20只健康豚鼠随机分为实验组和对照组,每组10只,实验组(膜迷路积水模型组)豚鼠腹腔注射醋酸去氨加压素,4μg·kg-1·d-1,共1周,诱导其内耳膜迷路积水,对照组豚鼠腹腔注射等量生理盐水。用免疫组化方法检测两组豚鼠内耳水通道蛋白的表达,并进行比较。结果对照组豚鼠内耳中有AQP0、1、2、3、5、7、8的表达,其中AQP0仅在血管纹和螺旋神经节细胞有较弱的表达;AQP1分布于包绕骨迷路、内淋巴囊、内淋巴管的纤维细胞,基底膜鼓阶面细胞、螺旋韧带纤维细胞、螺旋缘纤维细胞、Corti’s器、内外螺旋沟、血管纹、椭圆囊壁、球囊壁、螺旋神经节等;AQP2表达在血管纹、Corti’s器、螺旋神经节细胞和内淋巴囊中;AQP3、7、8三者的分布类似,在螺旋神经节和包绕膜迷路的组织中表达,包括Corti’s器、内外螺旋沟、血管纹、螺旋韧带纤维细胞、螺旋缘、椭圆囊壁、球囊壁、内淋巴囊等;AQP5则表达在Corti’s器、内外螺旋沟、螺旋神经节、螺旋韧带纤维细胞。实验组豚鼠内耳中,血管纹AQP2的表达与对照组较正常豚鼠表达增加,其它亚型AQPs的表达与对照组无明显差异。结论正常豚鼠内耳中有多种AQPs表达,膜迷路积水后豚鼠内耳中AQP2的表达增强,提示膜迷路积水可能与AQP2表达上调有关。

Objective To study the expression of aquaporins（AQPs） in the inner ear of normal guinea pig and guinea pigs with endolymphatic hydrops, and to investigate the mechanism and significance. Methods The guinea pigs were divided into two groups randomly： model group and control group. The guinea pigs in model group were given desmopressing 4 μg · kg^ -1 · d ^-1 introperitoneally for 1 week, while the guinea pigs in control group were giv en saline. After one week, the expression of AQPs in the inner ears of all guinea pigs was evaluated. Results Expression of AQP0, 1, 2, 3, 5, 7 and 8 were found in the ears of normal guinea pigs. Weak expression of AQP0 was found in stria vascularis and spiral ganglion. The distribution of AQPI consisted of cellular lining the bony labyrinth, fibrocytes lining in the endolymphatic duct and sac, cells under the basilar membrane, fibrocytes of the spiral ligament and the spiral limbus, Corti＇s organ, inner and outer spiral sulcus, stria vascularis, saccular and utricular wall, and spiral ganglion. AQP2 were found in stria vascularis, Corti＇s organ, spiral ganglion and endolymphatie sac. AQP3, 7 and 8 were distributed in a similar manner as the surrounding membranous labyrinth, including Corti ＇s organ, inner and outer spiral sulcus, stria vascularis, fibroeytes of the spiral ligament and the spiral limbus, saccular and utricular wall, endolymphatic sac and spiral ganglion. AQP5 was found at Corti＇s organ, inner and outer spiral suleus, spiral ganglion and fibrocytes in spiral ligment. The AQP2 in stria vascularis and endolymphatic sac was stronger in the inner ears with ELH than that in normal ears. Oonclusion There are various AQPs in inner ears of normal guinea pigs, and their distributions are overlapping and without obvious regional specificity, Desmopress ing induces the expression of AQP2 in the inner ears of guinea pigs. The results indicate that ELH may correlate to upregulation of AQP2, but the mechanism remains unclear.