Sirtuin 1激活在氯化钴诱导的离体耳蜗缺氧损害中的作用研究

目的观察氯化钴（CoCl2）对耳蜗毛细胞和神经节细胞的损伤模式并探讨Sirtuin 1（SIRT1）在耳蜗缺氧过程中的作用。方法采用CoCl2作用于离体培养的新生大鼠耳蜗组织，通过细胞化学染色和免疫荧光染色确定CoCl2对耳蜗毛细胞存活的影响，采用实时定量PCR方法检测CoCl2作用耳蜗组织后Sirtuin 1mRNA表达的变化。同时使用Sirtuin1激活剂白藜芦醇和Sirtuin 1抑制剂Sirtinol，观察SIRT1在缺氧介导的耳蜗损伤过程中的作用。结果300μmol／L以上浓度CoCl2作用于耳蜗24h可引起内外毛细胞缺失。细胞肿胀明显，神经元胞体变得不规则，数目明显减少，有些神经纤维甚至断裂。CoCl2处理后可引起早期耳蜗组织Sirtuin1基因表达增强，6h达到峰值。白藜芦醇预处理可以显著提高外毛细胞（P〈0．01）和内毛细胞的存活率（P〈0．05）。同时给予Sirtuin1抑制剂Sirtinol，白藜芦醇的保护效应被抵消。结论CoCl2导致耳蜗组织缺氧损害。耳蜗在缺氧过程中Sirtuin1早期上调，可保护耳蜗组织对抗缺氧诱导的细胞损伤。

The Protective Effects of Sirtuin 1 Activation against Hypoxia-induced Cochlear Damage in Vitro

Objective To observe the pattern of damage to cochlear hair cells and spiral ganglion neurons（SGN） induced by CoCl2 and to eand cultured, and treated with different concentrations of CoCl2. Cytochemical and immunofluorescence staining were performed to determinexplore the role of the Sirtuin 1 （SIRT 1）in the process of cochlear hypoxia. Methods The rat cochlear tissues were isolated the effects of CoCl2 on hair cells and SGNs. Sirtuin 1 gene change was detected by real time PCR assay at different time points after CoCl2 treatment. Resveratrol, an activator of Sirtuin 1, and Sirtinol, an inhibitor of Sirtuin 1, were used to observe the role of Sirtuin 1 in the process of hypoxia-mediated cochlear damage. Results 300 μmol / L or higher concentrations of CoCl2 can cause inner and outer hair cell loss in the cochlear explants, cell swelling, irregular shapes of SGN bodies, the decreasing number of SGNs or even nerve fiber rupture. Sirtuin 1 gene expression in cochlear explants was up-regulated at early stage after CoCl2 treatment. Resveratrol pretreatment can significantly improve the viability of outer hair cells （P〈0.01） and inner hair cells （P〈0.05）. The protective effects of resveratrol can be offset by Sirtinol. Conclusion CoCl2 can cause hypoxic damage in cochlear explants and up-regulate Sirtuin 1 gene expression at the early stage. Sirtuin 1 may play a protective role against hypoxia- induced cochlear cell damage.