| ObjectiveBy observing the contrast 36 v,110 v,220 v voltage of before and after the death of three sets of electrical injury of rabbit skin organization HE staining,immunohistochemical study HSP70 and HIF-1 forensic pathology change,studies three groups of different voltage,lifetime and after,and after the death of the relationship between different time shock and current plaque,discuss current plaque formation,mechanism and the value of the current spot index,exploration and HSP70 HIF-1 diagnostic value in current skin damage,provide a reference for electrical skin damage identification of forensic pathology.Methods35 rabbits were selected and randomly divided into 2 groups of 36 V,110V and 220 V shock groups before and after death and the normal control group,a total of 7 groups with 5 rabbits in each group.Living electric shock group: The rabbits were anesthetized with 10% chloral hydrate 2ml/kg and depilated with depilatory agent.The rabbit skin was subjected to pre-natal electric shocks(contact time: 1s,contact strength: slightly indentated skin,contact surface: maximum contact area at the end of the electrode is 0.6cm x 0.1cm)with self-made voltage-regulating shock device at 36 V,110V and 220 V respectively.The ear vein air embolism site was taken immediately after the experiment was completed.After death of the experimental animals,the contact skin was taken and sliced according to the routine pathological procedure..After death shock group: The rabbits were anesthetized with 10% chloral hydrate 2ml/kg and depilated with depilatory agent.The experimental animals were killed by auricular vein air embolism.Each limb of the experimental animals was divided into three regions,totally 12 regions.The rabbits were subdivided into three regions according to the voltage of 36 V,110V and 220 V.The rabbits were subdivided into five minutes,15 minutes,30 minutes,1h,2h,3h,4h,6h,7h,8h and 9h by self-made voltage regulating device.Electric shock(contact time: 1s,contact strength: slightly indentated skin,contact surface: maximum contact area at the end of the electrode is 0.6cm x 0.1cm).Skin samples were prepared according to routine pathological slicing procedure.Normal control group: The rabbits were anesthetized with 10% chloral hydrate 2ml/kg and depilated with depilatory agent.The experimental animals were killed by auricular vein air embolism.The skin of the limbs was taken immediately after death,5 minutes,15 minutes,30 minutes,1 hour,2 hours,3 hours,4 hours,5 hours,6 hours,7 hours,8 hours and 9 hours after photography and fixation,and the sections were prepared according to the routine pathological procedure.The gross morphology of the skin of each group was observed,and the sections of the above groups were stained with HE and then sealed for microscopic comparison of pathological changes.Wax blocks in the pre-life shock group,post-death shock group and the normal control group were selected.After biopsy,hif-1 and HSP70 immunohistochemical staining were used to prepare pathological sections for microscopic examination,and the immunohistochemical results were determined and statistically analyzed to explore the identification value of hif-1 and HSP70 in the current spot injury.Results1.No changes were observed in the skin histology of 36 V electric shock before and after death;The changes of current spots were observed in 110 V and 220 V electric shocks at different times before and after death,and there was no difference in the shapes of current spots formed by the electric shocks before and after death,but the current spots formed by 220 V electric shocks on the skin were more obvious than that by 110 V electric shocks.2.Positive expression of HIF-1 was found in the living control group and the 36 V,110V and 220 V shock groups,and the intensity increased with the increase of shock voltage.High expression of HIF-1 was observed in subcutaneous fibroblasts stimulated by 36 V,110V,and 220 V currents,while low expression was observed in subcutaneous fibroblasts in the control group.The three groups were compared with the control group,and only the 220 V group showed statistically significant difference(P=0.003<0.01),that is,HIF-1 immunohistochemical staining showed statistically significant difference in the 220 V group.The comparison between the three groups was statistically significant(P=0.049<0.05),indicating that there was a statistical difference between the three groups with HIF-1 immunohistochemical staining.3.Positive expression of HSP70 was found in the living control group and the 36 V,110V and 220 V shock groups,and the intensity increased with the increase of shock voltage.Hyperexpression of HSP70 in subcutaneous fibroblasts was stimulated by 110 V and 220 V electric currents before death.Low expression of HSP70 in subcutaneous fibroblasts of 36 V and control group.There was no statistical difference between the three shock groups and the control group,that is,there was no statistical difference between the three shock groups and the control group with HSP70 immunohistochemical staining.The comparison between the three groups showed significant statistical significance(P=0.004 < 0.01),indicating that there was a significant statistical difference in the immunohistochemical staining of HSP70 between the three groups.4,36 v,110v and 220 v voltage in 5min,15 min,30 min after death,1h,2h,3h,4h and 5 h shock group and control group after the death of the skin for examination by immunohistochemical staining HIF-1,36 v electric shock after the death of a different time group into subcutaneous tissue fiber cytoplasm expression weakly positive HIF-1,5min after the death of statistical analysis,30 min,1h,2h,5h shock group and the control group was statistically difference(P<0.05),shock expression were significant differences between groups(P<0.01);5min and 15 min after the death of 110 v and 3h into subcutaneous tissue fiber cytoplasm shock group were no express HIF-1,the rest of the electric shock group is expression of different degree by statistical analysis after the death of 5min,15 min,2h,3h,4h,5h shock group and the control group was statistically difference between groups(P<0.05),shock to express obvious statistical significance(P< 0.01);HIF-1 expression was observed in the subcutaneous fibroblast cytoplasm of the 220 V shock group at different time after death,and the difference between the shock group and the control group was statistically significant(P<0.05)and(P=0.006<0.05).5.36 v,110v and 220 v voltage in 5min,15 min,30min after death,1h,2h,3h,4h,5h shock group and control group after the death of the skin for examination by HSP70 immunohistochemical staining,at different times after the death of 36 v electric group into subcutaneous tissue fiber cytoplasm expression HSP70 weak positive,after statistics analysis and 30 min after the death of 1 h electric group compared with control group with statistical difference(P<0.05),the comparison between electric shock way without statistical significance;The HSP70 expression in the subcutaneous fibroblast cytoplasm of the shock group at different time after 110 V death was positive to different degrees,and the difference between the shock group and the control group at 15 min after death was statistically significant(P<0.05),and the difference between the shock groups was statistically significant(P<0.001).5 min,15 min after the death of 220 v,4h and 5h cytoplasm are yellow dye,subcutaneous tissue HSP70 weakly positive expression,2h and 3h after the death of subcutaneous tissue were no yellowing of the cytoplasm and negative of HSP70 expression,after statistics analysis and 15 min after the death of 4h electric group compared with control group with statistical difference(P<0.05),electric shock is compared between group was statistically significant(P<0.001).6.Immunohistochemical staining comparison of HIF-1 expression in the same voltage shock before death and after death showed statistically significant differences between the 36 V shock group before death,1h and 2h after death(P < 0.05).There were statistically significant differences between the 110 V shock group before and after death at 15 min,2h,3h,4h and 5h(P < 0.05).There were statistically significant differences between the 220 V group before and after death at 15 min,2h,3h and 4h(P < 0.05).7.Immunohistochemical staining comparison of HSP70 expression at the same voltage during the life and after death showed statistical significance after statistical analysis(P < 0.05).There were statistically significant differences between the 110 V shock group before and after death at 15 min,1h and 5h(P < 0.05).There were statistically significant differences between the 220 V group before and after death at 15 min,30min,1h,2h,3h and 5h(P < 0.05).ConclusionThere is a correlation between current spot and voltage intensity,and the higher the voltage,the more obvious the current spot is.The reason for the formation of electric current spot is the electric burn caused by the conversion of electric energy into heat energy,and the critical value of heat energy required for the formation of electric current spot exists.The electric current spot is an important basis for identifying electric injury,but it is not a reliable index to distinguish between pre-and post-mortem electric injury.That is to say,the electric current spot is not a necessary condition for identifying electric shock death.The existence of electric injury or even electric shock can be affirmed with electric current spot.No electric spot can exclude the effect of electric shock.HIF-1 and HSP70 can be used to distinguish different voltage shocks before and after birth in certain circumstances.HIF-1 and HSP70 are the diagnostic reference indexes of skin electric injury. |
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