运用猪眼视网膜细胞DNA降解程度推断死亡时间

DNA Degradation of Porcine Retinal Cells for Estimation of Postmortem Interval

目的运用单细胞凝胶电泳(single cell gel electrophoresis,SCGE)技术观察猪眼视网膜细胞DNA降解规律,推断死亡时间(postmortem interval,PMI)。方法猪死后取眼球放置于避光、温度(15±2)℃、湿度(50±5)%条件下,分别于2、4、6、8、10、12、14、16、18、20、22、24 h提取猪眼球视网膜细胞,进行SCGE,荧光显微镜采集图像,并运用单细胞凝胶电泳图像分析系统(IMI 1.0)进行图像分析。结果死后2～24h,视网膜细胞DNA降解程度随着PMI延长而增加;头DNA含量(%)、LT/LH、IT/IH与PMI的回归方程分别为y=92.227-5.188 x+0.019 x2+0.001 x3(R2=0.971)、y=0.035e0.191x(R2=0.947)、y=0.099 e0.264x(R2=0.955)。结论运用SCGE检测视网膜细胞DNA降解情况有助于推断PMI。

Objective To investigate DNA degradation of porcine retinal cells by single cell gel elec-trophoresis（SCGE） for estimation of postmortem interval（PMI）.Methods Degradation of retinal cells was observed by SCGE at 2,4,6,8,10,12,14,16,18,20,22 and 24 h after death respectively,under the environmental conditions of being kept in dark place as well as a controlled temperature of（15±2） ℃ and humidity of（50±5）%.The comet pictures were captured by fluorescence microscope and analyzed by single cell gel electrophoresis（IMI 1.0）.Results From 2 h to 24 h postmortem,the degree of degradation of retinal DNA increased with the prolongation of PMI.The postmortem regression functions of head DNA%,LT/LH,IT/IH were y=92.227-5.188 x＋0.019 x^2＋0.001 x^3（R^2=0.971）,y=0.035e^0.191x（R^2=0.947）,y=0.099e^0.264x（R^2= 0.955）,respectively.Conclusion The examination of retinal cell DNA degradation by SCGE is useful for estimating PMI.