Cx43在老年性聋小鼠耳蜗中的表达及意义

Effect of Cx43 expression in cochlea of presbycusis mice on banded synaptic aging

目的研究Cx43在老年性聋小鼠耳蜗中的表达以及耳蜗带状突触的变化,为老年性聋的防治策略提供依据。方法选取16月龄C57BL/6J雄性小鼠6只作为老年组,随机选取12只3月龄C57BL/6J雄性小鼠均分为D-gal组和对照组,D-gal拟老年聋模型鼠组采用经典D-gal衰老模型制造方法,对照组同时长每天颈背皮下注射等体积生理盐水。麻醉后检测听觉脑干电位(ABR),扫描电镜观察耳蜗带状突触的变化,采用免疫印迹法和酶联免疫吸附测定法测定耳蜗Cx43蛋白的表达,比较各组间的差异。结果与对照组相比,老年组和D-gal组的ABR阈值明显升高,Cx43蛋白水平明显降低(P<0.05),耳蜗带状突触宽度缩小(P<0.05);而老年组和D-gal组间ABR阈值、Cx43蛋白表达及耳蜗带状突触宽度均无统计学差异;同时,Cx43蛋白表达量与听觉脑干电位ABR阈值及耳蜗带状突触宽度变化具有相关性(P<0.001)。结论Cx43蛋白在老年小鼠及D-gal老年聋模型鼠的耳蜗中表达降低,且其与耳蜗带状突触宽度呈正相关,与听觉脑干电位ABR阈值呈负相关,提示Cx43蛋白含量的改变影响耳蜗带状突触形态,其蛋白表达量的下降参与老年性聋的发生发展。

Objective To study the expression of Cx43 in the cochlea of presbycusis mice and the changes of cochlear ribbon synapses,and to provide evidence for the prevention and treatment strategy of presbycusis.Methods C57BL/6J male mice were divided into three groups:aged group and D-gal control group.Six 16-month-old C57BL/6J male mice were selected as aged group.Twelve 3-month-old C57BL/6J male mice were randomly divided into D-gal control group.After anesthesia,auditory brainstem potential(ABR)was measured,changes in cochlear ribbon synapses were observed by scanning electron microscopy,and the expression of Cx43 protein in the cochlea was measured by immunoblotting and enzyme-linked immunosorbent assay to compare the differences between the groups.Results Compared with the control group,the ABR threshold of the elderly D-gal group was significantly increased,the Cx43 protein level was significantly decreased(P<0.05),the width of cochlear ribbon synapses was reduced(P<0.05),but there was no significant difference in the ABR threshold,Cx43 protein expression and cochlear ribbon synapse width(P<0.05).Meanwhile,the expression level of C x43 protein was correlated with the ABR threshold of auditory brainstem potential and the changes of cochlear band synaptic broadband(P<0.001).Conclusion The expression of Cx43 protein is decreased in the cochlea of aged mice and D-gal aged deafness model mice,and it is positively correlated with the width of cochlear ribbon synapses and negatively correlated with the ABR threshold of auditory brainstem potential,suggesting that the level of Cx43 protein involved in maintaining the normal appearance of cochlear ribbon synapses,and the decreasing of it related to the occurrence and development of presbycusis.