MiR-122, miR-133a, and miR-206 as potential biomarkers for post-mortem interval estimation

BackgroudAccurate estimation of post-mortem interval (PMI) is crucial in forensic investigations. MicroRNAs (miRNAs or miRs) are small non-coding RNAs that remain relatively stable within the cell nucleus despite post-mortem changes.ObjectiveWe assessed three target genes (miR-122, miR-133a, and miR-206) for PMI estimation using 72 healthy adult male BALB/c mice exposed to two different temperatures (4 and 21degree celsius) at nine different time points over 10 days.MethodsInitially, the stability of the two reference genes (RNU6B and 5 srRNA) was evaluated using gene stability analysis tools (Delta Ct, Best Keeper, and Genorm) to select the optimal reference gene. RNU6B was found to be the most stable endogenous control. Subsequently, the expression patterns of miR-122, miR-133a, and miR-206 were analyzed within a 10-day PMI period using the heart, skeletal muscle, liver, and brain tissues.ResultsAt 4degree celsius, miR-122 levels significantly decreased on days 8 and 10 in all tissues, with only the liver showing significant changes at 21degree celsius. MiR-133a decreased over time in the heart, muscles, and brain, showing a dramatic decrease on days 8 and 10 in the heart and muscles at both temperatures. Although miR-206 levels decreased over time in muscles and liver at 4 degree celsius, these increased in the brain at 21 degree celsius, with no expression changes in other organs.ConclusionIn summary, miR-122, miR-133a, and miR-206 are potential PMI markers in heart and skeletal muscle tissues.