单细胞凝胶电泳分析死后小鼠骨骼肌细胞核DNA降解

Analysis of postmortem DNA degradation in skeletal muscle cells by singlecell gel electrophoresis in mice

目的研究小鼠死后骨骼肌细胞核DNA降解与死亡时间的关系。方法应用单细胞凝胶电泳(SCGE)技术结合荧光显微镜和专业的计算机图像分析技术,测定111只小鼠在死后72h内不同时间点骨骼肌细胞核DNA电泳形状的8项参数值,所得数据进行统计学分析。结果在个体死亡72h内,“彗星”的尾DNA含量比例、尾长、尾矩、O live矩、尾面积数值随时间的延长而增大;而“彗星”的头半径,头DNA含量比例和头面积数值则随时间的延长而减小。经对每个参数的测量值进行多项式运算,获得DNA降解趋势的二项式回归方程(P<0.001)和多元回归方程(P<0.0001),且均具有极显著性意义。结论在死后一定时间内,小鼠骨骼肌组织核DNA降解随死后经过时间的变化而呈一定规律性变化,DNA降解与死亡时间之间呈线性相关。

Objective To study the relationship between changes of DNA degradation and the postmortem interval. Methods 111 rats were recruited in the experimental study. DNA was extracted from murine skeletal muscle cells at different intervals from 0 to 72h postmortem and electrophoresized by single - cell gel electrophoresis （SCGE）, which was morphometrically analyzed by fluorescent microscopy with auto -analysis- image system. Results 8 parameters including the tail length, head radius, percentage of head DNA and tail DNA, tail moment, the olive moment, and the head area as well as tail area were measured, all of which varied greatly with the extension of postmortem intervals, indicating that the degradation rate and DNA content in the nucleus had a close relationship with postmortem interval from 0 to 72h postmortem in rats. A dual regression equation and a multi- regression equation were deduced（P 〈0. 001 and P 〈0. 0001 ）. Conclusion Nuclear DNA in murine skeletal muscle cells is time - dependently degraded within a certain period of postmortem, which is correlated linearly with postmortem interval.