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目的 探讨ROS对各种组织mtDNA的损伤情况 ,耳蜗mtDNA是否为ROS损伤的标靶。方法 应用套式PCR及分子克隆测序技术对 10只Sod1基因敲除小鼠及 5只同系野生型小鼠耳蜗、脑、肝脏、肾脏、脾脏、心脏及皮肤组织进行研究。结果 1 各组织mtDNA可检测到 3种缺失 ,常见的缺失为mtDNA386 7bp和mtDNA372 6bp缺失 ,mtDNA4 2 36bp缺失不常见。 2 mtDNA缺失在不同组织的含量有明显的不同 ,肝脏和肾脏组织含量最高 ,耳蜗、心脏和大脑组织其次 ,脾脏及皮肤组织含量最低。与野生型小鼠比较 ,Sod1基因敲除小鼠mtDNA在不同组织的缺失量是野生型小鼠的 3- 2 0倍 ,其中耳蜗组织mtDNA缺失量约是WT小鼠的 15倍。结论 缺乏Sod1的保护 ,ROS可以攻击各种组织mtDNA ,但具有明显的组织特异性 ,耳蜗mtDNA是其损害的敏感标靶。
Objective To investigate the damage of ROS to various tissues of mtDNA and whether mtDNA of cochlea is the target of ROS injury. Methods The cochlear, brain, liver, kidney, spleen, heart and skin tissues of ten Sod1 knockout mice and five wild type mice were studied by nested PCR and molecular cloning sequencing. Results 1 Three mtDNA deletions were detected in all tissues. The common deletions were mtDNA386 7bp and mtDNA372 6bp, and the deletion of mtDNA4 2 36bp was not common. The content of 2 mtDNA deletions in different tissues was significantly different, liver and kidney tissue content was the highest, followed by cochlear, heart and brain tissue, spleen and skin tissue content was the lowest. Compared with wild-type mice, the amount of mtDNA deletion in different tissues of Sod1 knockout mice was 3-20 times that of wild type mice, and the deletion amount of mtDNA in cochlea tissues was about 15 times that of WT mice. Conclusion Lack of Sod1 protection, ROS can attack various tissue mtDNA, but with obvious tissue specificity, cochlear mtDNA is a sensitive target for its damage.