Effect of temporary freezing on postmortem protein degradation patterns.

Area of Science:

• Forensic science
• Biochemistry
• Postmortem interval determination

Background:

• Accurate time since death estimation is crucial in forensic investigations.
• Current postmortem interval (PMI) methods have limitations in specific timeframes or case scenarios.
• Western blot analysis of muscle protein degradation shows promise for overcoming these limitations.

Purpose of the Study:

• To investigate the effects of freezing and thawing on postmortem muscle protein decomposition.
• To assess the reliability of Western blot analysis for PMI determination using preserved tissue samples.

Main Methods:

• Dismembered pig hind limbs were either non-frozen or thawed after 4 months of freeze-storage.
• Samples were decomposed at 30°C for 7 and 10 days.
• Muscle proteins were analyzed using SDS-PAGE and Western blotting to observe degradation patterns.

Main Results:

• Muscle proteins exhibited predictable degradation patterns over time.
• The freeze-and-thaw process had no significant impact on protein degradation patterns.
• Degradation products appeared in distinct phases, aiding in temporal assessment.

Conclusions:

• A freeze-thaw cycle with prolonged frozen storage does not significantly alter postmortem skeletal muscle protein decomposition.
• This finding supports the robustness of protein degradation analysis for PMI determination in forensic settings.
• The study provides crucial data from a porcine model to validate this method for forensic applications.