Lv Yehui, Tao Li, Hu Luyuyan, Du Chengqiang, Wang Hui, Zhang Heng, Hu Yikai, Chen Long
Institute of Wound Prevention and Treatment, School of Basic Medical Sciences, Shanghai University of Medicine & Health Sciences, Shanghai 201318, China.
Human Anatomy Teaching and Research Section, School of Basic Medicine, Inner Mongolia Medical University, Hohhot, Inner Mongolia 010059, China.
Leg Med (Tokyo). 2025 May;75:102626. doi: 10.1016/j.legalmed.2025.102626. Epub 2025 Apr 19.
Accurate determination of postmortem interval (PMI) and cause of death (COD) is a critical challenge in forensic pathology, with significant implications for criminal investigations. Traditional PMI estimation methods are based on macroscopic changes and are influenced by environmental factors and investigator subjectivity. Recent advances in molecular biology have shown that certain cellular structures, such as mitochondria, retain functionality after death, making them potential biomarkers for forensic assessment. As mitochondria play a central role in cellular metabolism and respond dynamically to post-mortem hypoxia, investigation of mitochondrial membrane potential (ΔΨm) may provide a quantifiable and objective method for estimating PMI.
We successfully isolated mitochondria from post-mortem tissues and cultured cells, confirming their purity and membrane integrity. Regression analysis showed a strong linear correlation between ΔΨm and PMI in brain, myocardium and skeletal muscle within the first 15-18 h postmortem, with skeletal muscle showing the highest correlation coefficient. ΔΨm values remained stable at different temperatures, suggesting that it is a robust biomarker for estimating PMI. In vitro experiments under hypoxic conditions revealed a transient increase in ΔΨm at 24 h, accompanied by ATP depletion, ROS accumulation and shifts in mitochondrial fission and fusion dynamics, indicating mitochondrial adaptation to oxygen deprivation.
These findings highlight ΔΨm as a promising temperature stable biomarker for early assessment of PMI. The observed mitochondrial adaptations suggest that ΔΨm-based models may improve forensic accuracy and provide insights into postmortem metabolic processes. Further validation with human postmortem samples is essential to refine these models and explore their applicability to COD determination.
准确确定死后间隔时间（PMI）和死因（COD）是法医病理学中的一项关键挑战，对刑事调查具有重大意义。传统的PMI估计方法基于宏观变化，受环境因素和调查人员主观性的影响。分子生物学的最新进展表明，某些细胞结构，如线粒体，在死后仍保留功能，使其成为法医评估的潜在生物标志物。由于线粒体在细胞代谢中起核心作用，并对死后缺氧做出动态反应，因此研究线粒体膜电位（ΔΨm）可能为估计PMI提供一种可量化且客观的方法。
我们成功地从死后组织和培养细胞中分离出线粒体，证实了它们的纯度和膜完整性。回归分析表明，在死后最初的15 - 18小时内，大脑、心肌和骨骼肌中的ΔΨm与PMI之间存在很强的线性相关性，其中骨骼肌的相关系数最高。ΔΨm值在不同温度下保持稳定，表明它是估计PMI的可靠生物标志物。缺氧条件下的体外实验显示，在24小时时ΔΨm短暂升高，同时伴有ATP消耗、ROS积累以及线粒体裂变和融合动力学的变化，表明线粒体对缺氧的适应。
这些发现突出了ΔΨm作为一种有前景的温度稳定生物标志物，可用于早期评估PMI。观察到的线粒体适应性表明，基于ΔΨm的模型可能提高法医鉴定的准确性，并深入了解死后代谢过程。用人死后样本进行进一步验证对于完善这些模型并探索它们在COD确定中的适用性至关重要。
