【摘要】 目的探讨大鼠死后骨骼肌细胞核DNA降解与晚期死亡时间的关系。方法 54只SD大鼠随机均分为0d、1d、3d、7d、21d、28d、35d、42d时间点组,采用断颈法处死后,在相应时间点采用常规HE染色观察和采用Hoechst33258荧光染色法检测DNA浓度、进行看家基因GAPDH PCR半定量,对骨骼肌DNA降解情况进行分析。结果 HE染色结果显示,随着死后时间的延长,骨骼肌的自溶程度增加,在死后7d,细胞核HE切片中细胞核基本消失。Hoechst 33258荧光定量和GAPDH PCR半定量分析显示,大鼠死后21d以内,DNA浓度及GAPDH的表达量迅速下降,期间各时间点之间均存在显著性差异(P=0.000),而在之后至42d期间,数值维持在一个较低的水平,组间无显著性差异。上述实验结果可相互印证。结论大鼠骨骼肌组织DNA含量死后21d内呈明显下降趋势,其变化规律可尝试用于晚期死亡时间推断。更多还原

【Abstract】 Objective To discuss the correlation between the degradation of skeletal muscle nuclear DNA and the later postmortem interval( PMI). Methods Fifty-four healthy Spregue-Dawley rats were randomly divided into different groups,and then sacrificed by cervical dislocation at 0d,1d,3d,7d,21 d,28d,35 d,42d time point. The change of structure were observed by hematoxylin-eosin staining under light microscope. To determine the DNA degradation of the skeletal muscle,the concentration of DNA was quantified by using Hoechst 33258 fluorescence,and the housekeeping gene GAPHD was semi-quantified by RT-PCR at corresponding time points. Results HE-stained sections showed autolysis degree was increased with the increasing postmortem interval and the cellular nucleus almost disappeared at 7d after death. The result of DNA quantification and GAPHD examination showed that the degradation of rat skeletal muscles DNA was significantly different within 21 d after death( P= 0. 000). Between the 3d and 42 d,the skeletal muscle DNA concentration maintained a lower level,and there was no significant differences between each group. The results mentioned above can validate each other. Conclusion The degradation of rat skeletal muscles nuclear DNA showed significant differences at PMI after 21 d and its degradation can be used for estimating the later postmortem interval.更多还原