法医学组织病理切片DNA的实时荧光定量分析

目的:运用TaqMan探针实时荧光定量扩增法,对法医学病理切片进行DNA定量分析,探讨切片组织类型、保存时间对DNA基因组的质量影响。方法:取14例尸检7个年龄段的新鲜组织样本,制作脑、心、肝、肾、脾、肺、肠等7类组织病理切片。以2个7阶拉丁方实验设计,将切片随机分组保存7 d、14 d、30 d、90 d、180 d、360 d、720 d。用硅珠法提取切片DNA,实时荧光PCR进行DNA定量。结果:同一类型组织的不同保存时间的切片DNA含量存在差异(P<0.01),保存1月以内的切片DNA含量下降不显著,半年以上的样本DNA含量下降明显;同一保存时间的不同组织类型之间的DNA含量存在差异(P<0.01),肺、肝、肾三种组织切片DNA含量相对较高;身源年龄组之间差异不显著(P>0.6)。结论:法医学病理组织切片DNA含量较低,为低拷贝模板,组织切片保存时间、组织类型是影响DNA质量的重要因素。

Quantitative analysis of DNA by real-time PCR for forensic pathological section

Objective:To investigate the effects of preserving period and tissue types of pathological sections on the quality of DNA genome for forensic science using real-time quantitative PCR detection with TaqMan probe-based gene analysis.Methods:The fresh tissue samples were obtained from 14 cases of autopsy by 7 death ages for preparing pathological sections of the brain,heart,liver,lung,spleen,kidney and ileum tissue,and randomly maintained these sections for 7,14,30,90,180,360 and 720 days,respectively,in accordance with Latin square by double 7-order design.Silicon bead method was used to extract the DNA template that was further quantitatively detected using the real-time fluorescent quantitative PCR.Results:The DNA quantitative results varied a lot in the same kind of tissue sections preserved in dissimilar phase(P<0.01).No significant difference was seen in sections protected within one month,and yet,the DNA quantification was degraded significantly in those beyond 180 days.Also,the DNA content varied,to a certain extent,with diverse tissue sections kept for the same length(P<0.01),and the content was found relatively higher in sections of pulmonary,liver and kidney tissues.No significant difference was found concerning death ages(P>0.6).Conclusion:Forensic pathological tissue sections commonly exhibit lower content of DNA,i.e.,low copy number DNA,suggesting that the DNA nature is associated with the intervals of sections kept and tissue types.