强噪声暴露后豚鼠耳蜗细胞内质网应激相关因子表达的改变

目的:观察内质网应激相关因子Bip/GRP78和CHOP/Gadd153在强噪声暴露后豚鼠耳蜗细胞的表达,探讨内质网应激在强噪声暴露后豚鼠耳蜗细胞损伤中的作用。方法:选用健康雄性白色豚鼠48只,将实验组豚鼠暴露在4kHz窄带噪声120dBSPL噪声环境中4h,噪声刺激停止后1d、4d、14d组及对照组在处死前测ABR(每组各12只)。脱氧核糖核甘酸末端转移酶介导的缺口末端标记技术(TUNEIL)检测耳蜗凋亡细胞。免疫组化及Western Blot方法检测Bip/GRP78,CHOP/Gadd153蛋白的表达。结果:实验组耳蜗Corti/s器、血管纹(stria vascularis,sv)和螺旋神经节细胞(spiral ganglion cell,SGC)存在TUNEL阳性细胞,以1d组最多,而对照组未见阳性细胞。免疫组化、Western Blot检测实验组Bip/GRP78蛋白明显高于正常组,且在1d、4d、14d都维持在比较高的水平;CHOP/Gadd153蛋白含量在噪声刺激后迅速增高,1d、4d达到高峰,14d减少。结论:强噪声暴露启动内质网应激反应,诱导Bip/GRP78表达,降低细胞损伤,同时激活CHOP/Gadd153途径启动细胞凋亡来清除受害严重的细胞,这可能是内耳细胞内源性保护机制之一。

The Role of the Endoplasmic Reticulum stress-related Factors in Intense Noise-induced Cochlea Cells of Guinea Pig

Objective:To investigate the expression o f the endoplasmic reticulum-related factors Bip/GRP78 and CHOP/Gadd153 after intense noise exposed;To find out the relationship between Endoplasmic reticulum(ERS) and the Cochlea Cells damage after intense noise exposed.Methods:Forty-eight guinea pigs were randomly divided into 4 groups(12 rats in each group).The guinea pigs in the experiment groups were exposed to 4KHz narrow band noise at 120dB SPL for 4h.After the noise expose of 1,4,14days on the experiment guinea pigs,auditory brainstem response(ABR) of the guinea pigs in experiment and control groups were tested before killed.Apoptosis was tested by terminal deoxynucleotidyl Transferase(TdT)-mediated deoxyuridine triphosphate(d-UTP) nick and labeling method(TUNEL).Expression of Bip/GRP78,CHOP / Gadd153 were tested by immunohistochemistry and western blot methods.Results: There were higher expressions of Tunel-Positve cells in the OHC,SGC and SV of experiment groups and significant differences were observed compared with the control group(P<0.01.Protein levels of Bip/GRP78 and CHOP/Gadd153 were risen up after noise exposed,and there all have significant differences compared with the control group(P<0.01).Conclusion: The endoplasmic reticulum stress response was started after intense noise exposed and induced Bip/GRP78,CHOP/Gadd153 expression;that may be one of the mechanisms of endogenous protection.in inner ear cells.