The relationship between postmortem interval and protein changes in mice

Postmortem interval (PMI) estimation is important for forensic pathological autopsy. It has been reported that there is a correlation between certain protein changes in cadavers and PMI. However, no specific protein(s) has been used to determine the PMI so far. In this study, the total protein contents of mouse liver and spleen at different time of death were measured. The data showed that they were negatively correlated with the PMI. The degradation of beta-actin was found to be positively correlated with the PMI in the liver. Additionally, proteomic technique was used to study the changes of protein expression related to PMI in the liver of mice. By using Twodimensional electrophoresis, the expressions of four proteins were found to be significantly decreased and those of other three proteins were unchanged with the increase of PMI. Among the seven proteins, six were identified with peptide mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The three altered proteins were SBP2, ENOA, ALDH2 and three unchanged ones were 3HAO, TPIS, CATA, respectively. In the future, those unchanged proteins could be used as internal references to more accurately and reliably infer the time of death by assessing the level of changed proteins.

Automated summary

Postmortem interval (PMI) estimation is crucial in forensic pathology. This study reveals a negative correlation between total protein content and PMI in mouse liver and spleen, as well as a positive correlation between beta-actin degradation and PMI in the liver. Proteomic techniques were employed to identify protein expression changes related to PMI in the liver, leading to the discovery of four significantly decreased proteins and three unchanged proteins with the increase of PMI. These findings provide potential internal references for more accurate and reliable estimation of the time of death.