Temperature-dependent alterations in skeletal muscle during the postmortem interval: Structural, metabolic, and...

Area of Science:

• Forensic Science
• Molecular Biology
• Biochemistry

Background:

• Estimating the postmortem interval (PMI) is a critical challenge in forensic science.
• The influence of environmental temperature on postmortem skeletal muscle structural, metabolic, and transcriptional changes is not well understood.

Purpose of the Study:

• To investigate the effects of different environmental temperatures on postmortem skeletal muscle degradation.
• To characterize the temporal changes in skeletal muscle structure, energy metabolism, autophagy, and long non-coding RNA (lncRNA) expression at various postmortem intervals and temperatures.

Main Methods:

• Mice skeletal muscle samples were analyzed at multiple postmortem time points (0-36 hours) under controlled temperatures (4 °C, 20 °C, 30 °C).
• Histological, biochemical (adenylate energy status), and molecular analyses (autophagy markers, lncRNA sequencing) were performed.
• Quantitative PCR and polynomial regression were used to validate and model lncRNA expression patterns.

Main Results:

• Skeletal muscle deterioration, metabolic decline (ATP depletion), and autophagy marker changes were temperature-dependent, occurring faster at higher temperatures and slower at lower temperatures.
• Transcriptomic analysis revealed 1643 high-confidence lncRNAs, with distinct expression patterns influenced by temperature.
• Six candidate lncRNAs showed predictable, time-dependent expression trajectories across different temperatures, modeled with high accuracy (R² = 0.87-0.92).

Conclusions:

• Postmortem skeletal muscle undergoes structural, metabolic, and transcriptional alterations influenced by environmental temperature.
• These temperature-dependent molecular changes provide a potential basis for improving postmortem interval estimation in forensic investigations.