摘要
目的 通过体内实验探究二甲胺四环素对新霉素导致外毛细胞损伤的保护作用及其机制.方法 选用C57小鼠45只,雌雄不限,将小鼠随机分为对照组,新霉素处理组及新霉素+二甲胺四环素处理组,每组15只,测试3组小鼠听性脑干反应(auditory brainstem response,ABR)阈值;通过免疫荧光染色,比较3组外毛细胞存活情况;采用 cleaved caspase-3 染色及原位末端标记法(TdT-mediated dUTP-nick end labeling assay,TUNEL)染色,比较 3 组外毛细胞凋亡情况.结果 新霉素+二甲胺四环素处理组ABR阈值在各个频率均显著低于新霉素处理组,且ABR阈值在各个频率比较,差异均有统计学意义(P＜0.05).基底膜铺片显示,二甲胺四环素处理能显著减轻新霉素导致的外毛细胞损失.在对照组基底膜中,未检测到cleaved caspase-3和TUNEL阳性细胞;新霉素处理组,cleaved cas-pase-3 和TUNEL阳性细胞数量显著上升;新霉素+二甲胺四环素处理组,cleaved caspase-3和TUNEL阳性细胞数量显著下降.结论 二甲胺四环素对新霉素导致的外毛细胞损伤具有显著的保护作用,且这种保护作用是通过抑制外毛细胞凋亡通路而介导的.
Abstract
Objective To investigate protection against neomycin induced damage of outer hair cells by minocy-cline and potential mechanisms.Methods C57 mice of both genders(n=45)were randomly divided into control,neo-mycin and neomycin+minocycline groups(n=15 in each group).ABR thresholds were obtained and the rate of outer hair cells survival was compared by immunofluorescence staining among the three groups.Cleaved caspase-3 staining and TUNEL staining were used to compare outer hair cells apoptosis.Results ABR thresholds were significantly lower in the neomycin+minocycline group than in the neomycin only group at all frequencies(P＜0.05).No cleaved caspase-3 and TUNEL positive cells were detected in the basement membrane in the control group,while the number of such cells increased significantly in the neomycin group,as compared to the group treated with minocycline.Conclusion Minocy-cline provides significant protection against neomycin induced outer hair cell injury,probably mediated by inhibiting the apoptotic pathway.
维普
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