大鼠脑、骨髓细胞核DNA降解推断死后间隔时间的研究

目的检测大鼠死后不同温度下脑、骨髓细胞核DNA降解规律，寻找推断早期死亡间隔时间（PMI）的新参数。方法10℃和20℃下，大鼠死后0～40h内，每隔4h取材脑组织和骨髓，单细胞凝胶电泳（SCGE）检测DNA降解程度，线性回归分析比较彗星参数HeadDNA％、尾长（TL）、Olive尾矩（TM）与PMI的关系。结果大鼠死后早期脑细胞、骨髓细胞核Head DNA％随着PMI逐渐下降的程度不同，20℃脑细胞核Head DNA％降解速率较快。与骨髓细胞相比，脑细胞核Head DNA％与PMI线性关系较好。与TL、TM相比，Head DNA％与PMI的线性关系较好。结论脑组织是利用SCGE检测DNA降解推断PMI的合适检材。Head DNA％较TL、TM推断PMI的价值更高。

Estimation of the postmortem interval by determining nuclear DNA degradation from bone marrows and brains in rats

Objective To detect nuclear DNA degradation of bone marrows and brains in rat cadavers at different temperatures,and develop a new parameter for estimating early postmortem interval(PMI).Methods The brain and bone marrow were taken out for every 4h,during 0~40h after death at 10℃ and 20℃,respectively.And the single cell gel electrophoresis(SCGE) was carried out to detect the nuclear DNA degradation.Linear regression analysis was used to assay the relationship of the comet parameter HeadDNA%,Tail Length(TL) and Olive TailMoment(TM) with PMI.Results Different decline degrees of comet HeadDNA% were found in both brain cells and bone marrow cells after death,the decline of HeadDNA% in brain cells at 20℃ was faster.Compared with degradation in marrow cells,the linear relation between degradation of brain cells and PMI was better.Conclusion with that of comet parameters TL and TM,the perfect linear relationship between HeadDNA% and PMI was also observed.Conclusion Brain tissues are more suitable for PMI estimation by detecting degradation of DNA with SCGE.The HeadDNA% is more valuable for PMI estimation than TL and TM.