人脾组织DNA含量与死亡时间关系的显微拉曼光谱

摘要

Objective: To study the relationship between DNA degradation in spleen tissue cells and estimation of postmortem interval and to provide a new way for the estimation of postmortem interval (PMI). Methods: The spleen tissue in vitro obtained at different time points were kept in a controlled environment. Constitution of chemical group and DNA content in spleen tissue were examined by means of confocal Raman microspectroscopy with an excitation wavelength of 532 nm in the range of 800 cm-1 ～ 3200 cm-1. Results: The relative peak intensities (I1094/I2923) of RAMAN spectros for spleen tissue decreased gradually with prolongation of postmortem interval from 48 to 72 h after death. Peak intensity of relation to nucleic acid at peak position 1094 cm-1 was reduced obviously; Peak intensity of relation to lipid at peak position 1454 cm-1 and 2923 cm -1 did not change significantly; Peak intensity ratio (I1094/I2923) of confocal Raman microscopy was decreased with the prolongation of postmortem interval from 48 to 72h after death. Conclusions: DNA content in spleen tissue cells decreased gradually with the prolongation of postmortem interval fiom 48 to 72h after death. A linear relationship exists between relative peak intensities I1094/I2923 and postmortem interval (PMI). Thus,Confocal Raman Microspectroscopy is a potential method in the inference of postmortem interval.%目的:应用显微拉曼光谱技术探讨人体死亡后脾组织细胞DNA含量变化与死亡时间间隔(PMI)的变化规律,为推断死亡时间提供检测依据.方法:选取8例已知死亡时间的人体脾脏置于特定环境下,在死后48h～72h范围内不同时间点提取人脾组织样品,利用激光共焦显微拉曼光谱技术,在拉曼位移测试范围800 cm-1～3200 cm-1内检测样品的化学基团的构建及含量变化.结果:人死后48h～72 h内,随着PMI的推移,脾组织显微拉曼光谱的特征峰峰位没有发生明显变化,但特征峰峰高有明显变化;与核酸有关的峰位1094 cm-1处峰强度随PMI有明显下降趋势;与脂类有关的峰位1454 cm-1、2923 cm-1处的峰强随PMI变化不明显;每条谱线的相对峰强(I1094/I2923)随死亡时间的推移而减小.结论:人死亡后脾组织细胞DNA含量与PMI有明显的相关性.