Suh Myung Whan, Shin Dong Hoon, Lee Ho Sun, Park Ji Yeong, Kim Chong Sun, Oh Seung Ha
Department of Otorhinolaryngology, Seoul National University College of Medicine, Yongon-Dong, Chongno-Gu, Seoul 110-744, South Korea.
J Vestib Res. 2007;17(4):163-70.
Unlike mammals, avian cochlear hair cells can regenerate after acoustic overstimulation. The WDR1 gene is one of the genes suspected to play an important role in this difference. In an earlier study, we found that the WDR1 gene is over-expressed in the chick cochlea after acoustic overstimulation. The aim of this study was to compare the expression of WDR1 before and after acoustic overstimulation in the chick vestibule. Seven-day-old chicks were divided into three groups: normal group, damage group, and regeneration group. The damage and regeneration group was exposed to 120 dB SPL white noise for 5-6 hours. The damage group was euthanized shortly after the impulse, but the regeneration group was allowed to recover for 2 days. The utricle, saccule, and the three ampullae of each semicircular canal were dissected and immunohistochemically stained with anti-WD40 repeat protein 1 antibody. For quantitative analysis, immunoreactive densities were measured and quantitative real-time RT PCR was performed. WD40 repeat protein 1 expression was elevated in all the semicircular canals and utricle, two days after an acoustic overstimulation (P=0.001). WDR1 mRNA expression was 1.34 times higher in the regeneration group compared to the normal group, but it was not statistically significant. Exceptionally, WD40 repeat protein 1 expression did not increase in the saccule of the regeneration group. Elevated WDR1 expression in the avian vestibule may have a role in the hair cell regenerating ability as in the avian cochlea. A similar mechanism of hair cell regeneration may exist in the avian cochlea and vestibule.
与哺乳动物不同，鸟类的耳蜗毛细胞在受到过度声刺激后能够再生。WDR1基因被怀疑是造成这种差异的重要基因之一。在早期研究中，我们发现WDR1基因在受到过度声刺激后的雏鸡耳蜗中过度表达。本研究的目的是比较雏鸡前庭在受到过度声刺激前后WDR1的表达情况。将7日龄雏鸡分为三组：正常组、损伤组和再生组。损伤组和再生组接受120 dB SPL的白噪声刺激5 - 6小时。冲动后不久对损伤组进行安乐死，但让再生组恢复2天。解剖每个半规管的椭圆囊、球囊和三个壶腹，并用抗WD40重复蛋白1抗体进行免疫组织化学染色。为了进行定量分析，测量免疫反应密度并进行定量实时RT PCR。在声刺激后两天，所有半规管和椭圆囊中WD40重复蛋白1的表达均升高（P = 0.001）。再生组的WDR1 mRNA表达比正常组高1.34倍，但无统计学意义。例外的是，再生组球囊中的WD40重复蛋白1表达没有增加。鸟类前庭中WDR1表达的升高可能在毛细胞再生能力方面发挥作用，就像在鸟类耳蜗中一样。鸟类耳蜗和前庭可能存在类似的毛细胞再生机制。
