The effect of elapsed time on the cardiac Troponin-T (cTnT) proteolysis in case of death due to burn: A study to evaluate the potential forensic use of cTnT to determine the postmortem interval.

Background: After the death of an organism, intracellular enzymes cause protein to degrade into smaller fragments as the time passes, if these fragments can be isolated and visualized, and if the fragmentation is proved to be measurable and quantifiable, it can be a good sign of the post-mortem interval (PMI). The aim of this study is to evaluate the effect of PMI on Troponin-T protein degradation in cardiac tissues of cadavers through quantitative analysis of Troponin-T degradation by easily electrophoretic method and its association with PMI in case of deaths due to burn.

Methods: An efficient extraction protocol to analyze the banding pattern of cTnT in post-mortem tissue was developed. The analysis involves extraction of the protein (at different PMI (~7.30, 18.20, 30.30, 41.20, 41.40, 54.30..................88.40h), from the heart muscles of cadavers (burn cases), separation by denaturing gel electrophoresis (SDS-PAGE) and visualization by Western blot using cTnT specific monoclonal antibodies.

Results: The results specify a characteristic banding pattern amongst human cadavers (n=9), a pseudo-linear relationship between percent cTnT degraded and the time since death (r=0.87, p=0.0001). The area of the bands within a lane was quantified by scanning and digitizing the image using commonly available scanners.

Conclusions: The present research used a simple, easy, applicable and highly informative electrophoresis method that make it an ideal for the busy forensic laboratory. The post-mortem Troponin-T fragmentation observed in this study reveals a sequential, time-dependent process with the potential for use as a predictor of PMI in cases of burning. This result shows a potential for use as a future applied method of evaluating time since death.