【摘要】 目的：探究载脂蛋白E(apolipoprotein E,ApoE)基因缺陷引起小鼠耳蜗螺旋神经节处听神经损伤的可能机制。方法：对ApoE基因敲除（ApoE-/-）小鼠进行听性脑干反应（auditory brainstem response,ABR）检测，并分析波群振幅及延迟期。免疫荧光及HE染色分析耳蜗螺旋神经节内听神经及带状突触的病理损伤情况。蛋白质印迹、q RT-PCR等实验检测Lim激酶1(LIM domain kinase 1,Limk1)、丝切蛋白1(cofilin1)蛋白表达及磷酸化水平，并检测磷脂酰肌醇3激酶（phosphatidylinositide 3-kinases,PI3K）通路激活情况。结果：ApoE-/-小鼠ABR检测中波Ⅰ的振幅缩短，延迟期延长。螺旋神经节处染色结果显示ApoE-/-小鼠带状突触及听神经纤维数量减少，并伴随结构受损。Western blot、qRT-PCR及免疫荧光染色发现Limk1与cofilin1在ApoE敲除后蛋白磷酸化水平出现显著性下降，同时PI3K通路激活被抑制。结论：ApoE基因缺陷会引起耳蜗螺旋神经节处带状突触及听神经损伤，并可能与神经元肌动蛋白细胞骨架密切相关。更多还原

【Abstract】 Objective:The current study aims to investigate the possible mechanism of auditory nerve injury at the spiral ganglion of the cochlea induced by apolipoprotein E(ApoE) gene deficiency in mice. Methods:Auditory brainstem response(ABR) were measured in ApoE knockout(ApoE-/-)mice,and the amplitude and latency of the wave groups were analyzed. Immunofluorescence and H&E staining were used to analyze the pathological damage of auditory nerve and ribbon synapsesin the spiral ganglion. Western blot and qRT-PCR were used to detect the protein expression and phosphorylation levels of LIM kinase 1(Limk1)and cofilin1,and to detect the phosphatidylinositide 3-kinases(PI3K)pathway activation. Results:The amplitude of wave Ⅰ in ApoE-/-mice by ABR was shortened and the latency was prolonged. The spiral ganglion staining showed that the number of ribbon synapses and auditory nerve fibers were reduced in ApoE-/-mice,accompanied by the structural damage. Western blotting,q RT-PCR and immunofluorescence staining revealed that Limk1 and cofilin1 showed a significant decrease in protein phosphorylation levels after ApoE knockdown,while the PI3K pathway activation was inhibited. Conclusion:ApoE gene deficiency could damage the ribbon synapse and auditory nerve at the spiral ganglion of the cochlea,which might be related to the actin cytoskeleton of theauditory nerve.更多还原