Şenbaş Z. A. (Executive), Orhan N., Arıcan N.
TUBITAK Project, 2022 - 2023
Objective: Although there are many methods used to estimate the time of death, the standard deviation in the evaluations is quite high, so the estimation intervals are quite wide. In this study, it was aimed to predict the postmortem interval (PMI) with shorter standard deviations than the existing methods by mRNA (messenger RNA) expression analysis in postmortem skeletal muscle tissues.
Method: HIF1A (Hipoxy-induced factor 1 alpha), ACTB (Beta- actin), B2M (Beta-2-microglobulin), PPIA (Peptidyl isomerase A) and GAPDH (Glyceraldehyde 3-Phosphate Dehydrogenase) mRNA expression levels were measured by RT-PCR (real-time polymerase chain reaction) technique along with total RNA levels. For this purpose, psoas major muscle samples were collected from cases sent to the Morgue Specialization Department of the Forensic Medicine Institute for forensic autopsy and whose time of death is known.
Results: There was no statistically significant correlation between total RNA (ribonucleic acid) values and PMI. There was a weak negative correlation between B2M Ct (cycle of threshold) values and PMI groups (r = -0.210, p = 0.045). With this, there is a weak negative correlation between Ct values of the same gene and PMI hour numbers (r = -0.232, p = 0.027). For normalization, Ct values obtained for HIF1A, B2M and ACTB genes were sorted with RefFinder software and it was determined that ACTB was the most stable gene among those three genes.
Conclusion: It has been determined that RNA can be isolated from skeletal muscle in the first 24 hours postmortem under forensic autopsy conditions, total RNA level alone is not a reliable marker in the estimation of PMI, and mRNA expression level measured by absolute value analysis of B2M may be useful for this purpose. It has been determined that ACTB can be used as a reference gene in postmortem skeletal muscle tissue for normalization purposes.