ATF3 mRNA, but not BTG2, as a possible marker for vital reaction of skin contusion.

The detection of vitality of wounds, especially when the wounds are inflicted very close to the time of death, is one of the most challenging issues in forensic pathology. This study investigated expression levels of ATF3 and BTG2 in mouse and human skin wounds. Protein levels examined by western blot showed that there was no significant change in ATF3 and BTG2 between wounded and intact skins. However, mRNA levels demonstrated higher expression of ATF3 and BTG2 in ante-mortem contused mouse skins, compared with the intact and postmortem contused skins. Increased ATF3 and BTG2 in the level of mRNA could also be detected until 96h and 48h after death, respectively. Human wounded skin samples from forensic autopsy cases were also examined. Increased ATF3 mRNA levels were detected until 48h after autopsy in 5 of 6 cases. However, no differences were observed between wounded and intact skins for BTG2. These findings suggest that the detection of mRNA levels of ATF3, but not BTG2, can be considered as a potential marker for vital reaction of skin contusion. Postmortem human samples should be used in order to validate the availability of markers screened by animal experiment.

RNA-seq profiling reveals differentially expressed genes as potential markers for vital reaction in skin contusion: a pilot study.

Detection of the vitality of wounds is essential in forensic practice. The present study used Illumina RNA-seq technology to determine gene expression profiles in contused mouse skin. In obtained high quality sequencing reads, the reads were mapped onto a reference transcriptome (Mus_musculus.GRCm38.83). The results revealed that there were 659 up-regulated and 996 down-regulated differentially expressed genes (DEGs) in contused mouse skin. The DEGs were further analyzed using the Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes databases. Genes from different functional categories and signalling pathways were enriched, including the immune system process, immune response, defense response, cytokine-cytokine receptor interaction, complement and coagulation cascades and chemokine signalling pathway. Expression patterns of 11 DEGs were verified by RT-qPCR in mice skins. In addition, alterations of five DEGs were also analyzed in postmortem human wound samples. The results were in concordance with the results of RNA-seq. These findings suggest that RNA-seq is a powerful tool to reveal DEGs as potential markers for vital reaction in terms of forensic practices.

IL-6 and IL-20 as potential markers for vitality of skin contusion.

The detection of vitality of wounds is very important in forensic practice. This study is performed using quantitative real-time reverse transcriptase polymerase chain reaction (RT-qPCR) in both mouse and human skin wounds for the application of IL-6 and IL-20 in order to differentiate intravital wounds from postmortem wounds. RT-qPCR analysis of contused mouse skin showed that increased IL-6 and IL-20 mRNA levels were found in comparison to intact skin tissues. The increased mRNA expressions of IL-6 and IL-20 were observed until 72 h after death in contused mouse skin, whereas there were no marked changes in these two cytokines in the postmortem contusion group. The alterations of IL-6 and IL-20 can also be detected in human skin wound samples. These finding suggest that mRNA levels of IL-6 and IL-20 might be used as potential markers for vital reaction.

CXCL1 and CXCR2 as potential markers for vital reactions in skin contusions.

Detection of the vitality of wounds is one of the most important issues in forensic practice. This study investigated mRNA and protein levels of CXCL1 and CXCR2 in skin wounds in mice and humans. Western blot analysis of CXCL1 and CXCR2 protein levels showed no difference between wounded and intact skin. However, mRNA levels demonstrated higher expression of CXCL1 and CXCR2 in contused mouse and human skin, compared with intact skin. At postmortem there were no remarkable changes in CXCL1 and CXCR2 mRNA levels in contused mouse skin. Increased mRNA expression was observed in contused mouse skin up to 96 h and 72 h after death for CXCL1 and CXCR2 respectively. In human samples of wounded skin, increased CXCL1 mRNA levels were detected up to 48 h after autopsy in all 5 cases, while increased CXCR2 mRNA levels were observed 48 h after autopsy in 4 of 5 cases. These findings suggest that the levels of CXCL1 and CXCR2 mRNA present in contused skin can be used as potential markers for a vital reaction in forensic practice.