Forensic Pathology Study Of Rat Skin Incisions And Wounds Before And After Death

ObjectiveBy observing and comparing the skin wounds,HE staining and EⅢA-FN immunohistochemical and forensic pathological changes of sharp instrument injury at different time before and after death in rats at different time within 24 h after death.To study the macro changes of wound at different time after antemortem and postmortem,the morphological changes of HE tissue,whether local incision and wound induced systemic EⅢA-FN reaction,the relationship between injury time and the content of EⅢA-FN in the skin of incision and wound,the comparison of the content of EⅢA-FN in the skin of incision and wound,and the effect of different time after death on the content of EⅢA-FN content,and to explore the causes of wound duo to open and HE the value of the microscopic organization form in forensic medicine,explore EⅢA-FN in identification was wounded and dead after application value,provide A reference for forensic pathology of mechanical damage identification.MethodsForty-five SD rats were randomly divided into 9 groups with 5 rats in each group,including 15 min,0.5h,1h,2h,4h,8h injury group,15 min injury group immediately after death and normal control group.Will by intraperitoneal injection of rats after anesthesia,take off limbs and back hair,the corresponding time point with the outside of sterile knife on the limbs segment production cut 1 cm long,deep fascia,no dress,in after the death of2 h,4h,8h,24 h to macroscopic pathology observation,each skin injury group take cutting edge we now skin skin white space and back,The skin of the normal control group and the injured group were taken from the same part of the incision and wound,and HE staining and immunohistochemical staining(SP method)were performed according to the routine pathological procedures.The pathological morphological changes and expression changes of EⅢA-FN were compared under microscope,and the immunohistochemical staining results were analyzed by image and statistics.To explore the application value of EⅢA-FN in differentiating the antemortem and postmortem injuries of sharp instruments.Results1.Both the antemortem injury group and the postmortem injury group had the phenomenon of multiple opening.There was inflammatory cell infiltration in the injured group at 4 and 8 hours before the death,and no obvious histomorphological changes were observed in the other groups.At 2h,4h,8h and 24 h after death,there were no significant changes in the whole skin layer.2.Expression of EⅢA-FN: The expression of EⅢA-FN was found in the epidermis,sebaceous glands and hair follicles of the incised and incised skin in the pre-injury group.The expression of EⅢA-FN in sebaceous glands of self blank control group,postmortem injury group and normal control group was observed.3.Comparison of the expression level of EⅢA-FN in the skin of incision and wound and the skin of blank control group: the expression level of EⅢA-FN in the skin of incision and wound and the skin of blank control group had statistical significance(P<0.05);Immediately after the death of injury group,A cutting edge area with its blank controls skin after death 2h EⅢA-FN expression difference was statistically significant(P<0.05),in 4h,8h,24 h after the death of no statistical significance(P>0.05);There was no significant difference in the expression of EⅢA-FN in the skin of the injured group and the blank control group 15 min after death(P>0.05).4.Comparison of the expression level of EⅢA-FN in the skin of incision and wound between the injury group: the expression level of EⅢA-FN in the skin of incision and wound between the injury group was statistically significant(P<0.05).There was no significant difference in the expression of EⅢA-FN in the skin of the postmortem injury group at 2h postmortem(P>0.05)),the expression level of EⅢA-FN in skin was significantly different at 4h,8h and 24 h postmortem(P<0.05).5.Comparison of the expression level of EⅢA-FN in incisor skin between antemortem injury group and postmortem injury group: the expression level of EⅢA-FN in incisor skin between antemortem injury group and postmortem injury group was statistically significant(P<0.05).There was no significant difference in the expression level of EⅢA-FN in the injured group and the injured group immediately after death(P>0.05).There was no significant difference in the expression level of EⅢA-FN in the15 min injury group and the 15 min injury group at 2h and 4h after death(P>0.05),but there was significant difference in the expression level at 8h and 24 h after death(P<0.05).6.There was no significant difference in the expression of EⅢA-FN at 2h,4h,8h and 24 h after death(P>0.05).ConclusionWithin 15 minutes after death,the skin was hyperreactive to sharp instrument stimulation,and the wound opening could not be used as a reliable index for the diagnosis of antemortem injury.HE histomatological observation is necessary to distinguish antemortem injury from antemortem injury.Local skin injury will not cause systemic skin EⅢA-FN changes.There was A positive correlation between the time of early skin injury and the expression level of EⅢA-FN.The expression of EⅢA-FN could distinguish the injury with time of more than 0.5h before death from injury within 15 min after death,and different time within 24 h after death had no influence on the expression of EⅢA-FN.EⅢA-FN is expected to be an index to distinguish antemortem injury from postmortem injury in forensic pathology.