ApoE敲除导致小鼠耳蜗螺旋神经元功能损伤  

Functional impairment of cochlear spiral neurons caused by ApoE defect in mice

作　　者：汤序军 王红顺 姚俊[1] 曹新[1] TANG Xujun;WANG Hongshun;YAO Jun;CAO Xin(Department of Medical Genetics,Nanjing Medical University,Nanjing 211166,China)

机构地区：[1]南京医科大学医学遗传学系,江苏南京211166

出　　处：《南京医科大学学报（自然科学版）》2023年第2期156-163,168,共9页Journal of Nanjing Medical University(Natural Sciences)

基　　金：国家自然科学面上项目(32070587)。

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。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 waveⅠin 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.

关 键 词：载脂蛋白E 耳蜗 螺旋神经元 

分 类 号：R392.2[医药卫生—免疫学]