Shiiba Kyoko, Shindo Susumu, Ikezono Tetsuo, Sekine Kuwon, Matsumura Tomohiro, Sekiguchi Satomi, Yagi Toshiaki, Okubo Kimihiro
Department of Otorhinolaryngology, Nippon Medical School, Tokyo, Japan.
Acta Otolaryngol. 2012 Nov;132(11):1134-9. doi: 10.3109/00016489.2012.687456. Epub 2012 Sep 30.
The changes in the cochlin isoforms in the perilymph may provide important insights to the understanding of cochlin function and the pathogenesis of related inner ear diseases.
Cochlin is involved in various pathologies of the inner ear. Altered levels of cochlin isoforms in developing inner ear tissue were reported previously. The purpose of this study was to elucidate the cochlin isoform expression in the perilymph of rats during postnatal development in relation to Coch gene mRNA expression.
We studied the cochlin isoforms in the rat perilymph during postnatal development by Western blot analysis. Real-time PCR was also performed to elucidate the expression level of Coch mRNA in the developing inner ear of rats.
Western blot analysis showed that the expression of p63s in the perilymph was highest on the 12th day after birth (DAB12), the earliest age at which we could identify the perilymphatic space microscopically, and it decreased gradually as the cochlea developed. On the other hand, the expression of Cochlin-tomoprotein (CTP)was lowest on DAB12 and increased gradually up to DAB24. COCH mRNA was detected from DAB3 and gradually increased to DAB15, and then gradually decreased to DAB70.
外淋巴中耳蜗蛋白亚型的变化可能为理解耳蜗蛋白功能及相关内耳疾病的发病机制提供重要线索。
耳蜗蛋白参与内耳的多种病理过程。此前有报道称发育中的内耳组织中耳蜗蛋白亚型水平发生改变。本研究的目的是阐明出生后发育过程中大鼠外淋巴中耳蜗蛋白亚型的表达与Coch基因mRNA表达的关系。
我们通过蛋白质免疫印迹分析研究了出生后发育过程中大鼠外淋巴中的耳蜗蛋白亚型。还进行了实时定量PCR以阐明大鼠发育中的内耳中Coch mRNA的表达水平。
蛋白质免疫印迹分析显示，外淋巴中p63s的表达在出生后第12天（DAB12）最高，这是我们能够在显微镜下识别外淋巴间隙的最早年龄，并且随着耳蜗的发育逐渐降低。另一方面，耳蜗蛋白转位蛋白（CTP）的表达在DAB12时最低，并逐渐增加直至DAB24。从DAB3检测到COCH mRNA，并逐渐增加至DAB15，然后逐渐降低至DAB70。
