鸡胚低分子提取物对D-半乳糖拟衰老小鼠线粒体DNA缺失突变的影响

目的 探讨鸡胚低分子提取物对D-半乳糖诱导的衰老小鼠线粒体DNA(mtDNA)缺失突变的影响.方法 采用D-半乳糖诱导制备衰老小鼠模型并用鸡胚低分子提取物处理.用聚合酶链反应技术和琼脂糖凝胶电泳检测mtDNA缺失片段,密度扫描技术对扩增片段进行相对定量.缺失片段构建质粒后,直接测序进行鉴定.结果 全部小鼠的肝、大脑皮质与海马组织内均存在4239 bp的mtDNA缺失片段.衰老模型鼠不同组织mtDNA缺失的相对百分含量均明显高于正常对照组(均为P%0.01),而鸡胚低分子提取物可明显降低模型鼠肝、大脑皮质与海马组织内mtDNA缺失的比例(均为P＜0.05).肝组织中mtDNA缺失的比例较大脑皮质和海马组织更高.结论 4239 bp的mtDNA缺失片段普遍存在于小鼠中,鸡胚的低分子提取物可以明显减少D-半乳糖拟衰老小鼠4239 bp的mtDNA缺失的发生.

Effect of low molecular weight substance extracted from chick embryo on mitochondrial DNA deletion in aging mice induced by D-galactose

Objective To investigate the effect of low molecular weight substance extracted from chick embryo on mitochondrial DNA(mtDNA)deletion in senile mice induced bv D-galactose.Methods Senile mice induced by D-galactose were treated with low molecular weight substance extracted from chick embryo.The deleted fragment of mtDNA was examined by using polymerase chain reaction technique and agarose gel electrophoresis.A relative quantitation of band densities was performed by using densitometry scanning techniques.The deletion was identified by using direct sequencing analysis. Results The 4239 bD mtDNA deletion were present in liver,cerebral cortex and hippocampus tissues in all of the mice.and it was significantly higher in senile model mice than in control mice(all P＜0.01).Low molecular weight substance extracted from chick embryo reduced the mtDNA deletion in various tissues in senile model mice(all P＜0.05).Deletion was more abundant in liver than in cerebral cortex and hippoeampus. Conclusions The 4239 bp mtDNA deletion is a common deletion,and low molecular weight substance extracted from chick embryo could decrease the incidence of 4239 bD mtDNA deletion.