Skeletal muscle proteins: a new approach to delimitate the time since death.

PURPOSE: Skeletal muscle tissue is proposed as a forensic model tissue with strong potential, as it is easily accessible and its true-to-life state structure and function is well known. Despite this strong potential, skeletal muscle degradation studies are rare. The aim of this study was to test if a skeletal muscle-based protein analysis is applicable to delimitate the time since death.

METHODS: Under standard conditions, two pigs were stored either at 22 °C for 5 days or 4 °C for 21 days. Their Mm. biceps femori were sampled periodically for analyses of ten skeletal muscle proteins postmortem.

RESULTS: All analyzed proteins can serve as markers for a delimitation of the time since death. Desmin, nebulin, titin, and SERCA 1 displayed distinct protein patterns at certain points of time. The other five proteins, α-actinin, calsequestrin-1, laminin, troponin T-C, and SERCA 2, showed no degradation patterns within the analyzed postmortem time frame.

CONCLUSIONS: Referring to specific skeletal muscle proteins, results showed short-term stabilities for just a minority of analyzed proteins, while the majority of investigated proteins displayed characteristics as long-term markers. Due to specific patterns and the possibility to determine definite constraints of the presence, absence, or pattern alterations of single proteins, the feasibility of porcine skeletal muscle as forensic model tissue is outlined and the potential of skeletal muscle as forensic model tissue is underlined, especially with respect to later postmortem phases, which so far lack feasible methods to delimitate the time since death.