【摘要】 目的 观察minocycline对链霉素诱导的耳毒性的拮抗作用。方法选用新生4天的Wistar大鼠60只,分离耳蜗进行离体培养。随机分为4组,包括正常培养的对照组,100μmol/L的minocycline作用组,500μmol/L的硫酸链霉素作用组,100μmol/L的minocycline预处理6 h然后500μmol/L的硫酸链霉素作用组。采用F-actin标记毛细胞纤毛观察毛细胞存活情况。免疫组织化学染色法检测耳蜗基底膜3-硝基酪氨酸的表达。Western Blot:ing检测耳蜗组织中iNOS、3-硝基酪氨酸(3-nitrotyrosine,3-NT)的表达。结果500μmol/L的链霉素作用24 h后毛细胞出现缺失,从顶回至底回逐渐严重。支持细胞未见异常。免疫组化结果显示3-NT在毛细胞区域呈阳性表达。Minocycline预处理组能够提高链霉素作用后的毛细胞存活率,并且minocycline显著降低耳蜗组织由链霉素引起的iNOS和3-NT蛋白过表达。结论minocycline对链霉素所致的耳蜗毛细胞损伤有拮抗作用,其机制可能部分通过抑制NO的过度生成,以减少耳蜗细胞内过氧亚硝基阴离子(ONOO~-)产生的蛋白质硝基化反应。更多还原

【Abstract】 Objective To observe the role of minocycline in the protection of cochlear hair cells after the administration of streptomycin.Methods Wistar rats 4 days after birth were prepared and their cochlear membranes were isolated for in vitro experiments.The samples were randomly divided into 4 groups.One group was the normal control and the other three groups were treated with 500 μmol /L streptomycin,100 μmol/L minocycline and both.respectively.F-actin labeling was applied to detect the loss rate of hair cells and immunohistochemical staining was performed to detect the expression of 3-nitrotyrosine.Quantitative expressions of 3-nitrotyrosine and iNOS were confirmed by western bloting.Results Hair cells loss was seen and aggravated from apical to basal turn in the group treated with 500 μmol/L streptomycin.No change was found in supporting cells of cochleae.Immunohistochemical results showed the 3- NT positive expression in the region of the hair cells.Minocyline pretreatment group can improve the survival rate of hair cells after the administration of streptomycin and significantly reduced the excessive expression of iNOS and 3- NT in cochleae.Conclusion Minocycline can protect cochlear hair cells from damage caused by streptomycin and its mechanism may be the inhibition of excessive formation of NO to reduce the protein nitration in the cochlear hair cells.更多还原