UPLC/Q-TOF MS-based femoral muscle metabolomic analysis under high-temperature: a proof of concept for postmortem interval estimation.

Introduction: Accurate postmortem interval (PMI) estimation is a major challenge in forensic medicine, especially for the rapidly and highly putrefied bodies in tropical high-temperature areas. Despite numerous studies, there are still no reliable, objective methods to accurately estimate PMI for corpses found in a high-temperature environment. Methods: In the current research, an ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS)-based metabolomics approach was employed for the analysis of the metabolic profile of rat femoral muscle tissue in a high-temperature environment at different postmortem intervals. Multivariate pattern recognition and pathway analyses were employed for the identification of differential metabolites. Results: This study identified 14 significantly changed metabolites and two altered metabolic pathways. Among them, L-threonine, histidyl-threonine, L-tryptophan, N6-acetyl- L-lysine, eicosapentaenoic acid, glycerol 3-phosphate, and creatine were selected as possible diagnostic biomarkers for PMI estimation. Their impact value and potential biological function in the organisation's degradation process were the basis for selection. Discussion: This study demonstrated the feasibility of UPLC/Q-TOF MS-based metabolomics in femoral muscle tissue research and identified several differential metabolites that may provide forensic scientists with a helpful reference in PMI estimation in a high-temperature environment.