| Objective:Electrical injury and electrouction are the familiar cases in forensic medicine practice; but they are not easy to diagnose. Though there are many scholars tried their best to carry out a great deal of studies about them, if the typical changes of skin (such as the current marks,metallization of skin) is not existed,it is also difficult to diagnose.However, the typical changes of skin are so unusual in practical cases(one to three) that its application in legal medicine is limites treatly.So it is especially important to diagnose the electrical injury and electrouction which the typical changes of skin are not existed but as if them.It is reported that someone found PEG-3 significantly increase in the electrical injury cases, we study it by the method of immunohistochemistry and hybridization in situ in this experiment in order to discover the diagnostic value and the time expression dependability of PEG-3 in the electrical injury,electrouction and the postmotorm electrified.Methods:The animals were devided into two groups:the negative group and the experimental group.The experimental group were devided into three groups again: the electrical injury group, the electrouction group and the group of electrical shock after death. The electrical injury group is for 0h, 3h, 6h, 12h, 24h, 3d, 6d, 12d, the electrouction group is for 0h, 1h, 3h, 6h, 12h, and the group of electrical shock after death is for 0h, 0.5h, 1h, 3h,the control group is for 0h, 0.5h, 1h, 3h, 6h, 12h, total 23 groups ,three samples for each.The modelling methed for the negative group is to breakdown the neck to put to death, the electrical injury group is to shock the mouse for 30 seconds, the electrouction group is to put to death by electrical shocking and the group of electrical shock after death is to shock the mouse by electricity after breakdown the neck to put to death at the homologous time. After all these we should get the cardiac tissue at the propotional time, and then dye it by the method of HE, immunohistochemistry and hybridization in situ. We can gain the conclusion through the method of semiquantitative analysis at last.Results:The pathological changes of the electrical injury group and the electrouction group observed by HE dyeing as follows:From 3 hour to 6 hour ,poly-loci of myocardial cells denaturalization, necrosis and fragmentation, partial cells showed"wave-like"array and contraction bands necrosis; cytoplasm exhibiting homogenous and eosinophilic change, blurred cross striation; nuclear dakstaining, distoring, strenching and vacuolization; the myocardial interval broaden, edema and scattered bleeding; arterilole enlarging, nuclear of endothenial cells darkstaining, swelling, eosinophilic change of soomth cells, and hemaglutination; HBFP also showed multi-loci of ischemic myocardial cells. From 12 hour to 3 day, the scope of necrotic myocardial cells increasing, edema of the myocardial cells becoming more obvious, the little bands of fascle interval increasing and the transect of myocardiym exhibited"sieve-like"change; partial myocardial cells dissolution and neclear disappearance; vessel enlargingm nuclear of endothenial cells denaturalization, swelling and falling off, large number of red cells adhering on the wall of vessel, some neutrophil po;ymorphs aggulation and little of them leaked from vessel, transparent thrombus formation; a little loci of fibroblast and epimysium cells increasing.From 6 day to 12day, the scope pof necrosis was lager than pruvious observied, a great roll of film cardiac muscle myolysis and necrosis,and the spatium intermusculare obviously widen.The pathological changes of the electrical injury group and the electrouction group observed by immunohistochemistry and hybridization in situ dyeing as follows: there are very fortis positive staining in carcoplasm for the electrical injury group,increasing at once and at 12 hour ,it is to achieve the peak, sequentia taper. At 12 day , its value is still to remain super control group, but to get close the control group;It is also to submit the fortis positive staining for the electrouction group, increasing at once and at 3 hour ,it is to achieve the peak, sequentia taper. At 12 hour , its value is still to remain super control group, but to get close the control group; but there are only extremely tenuous positive staining for the negative control group and the group of electrical shock after death. All above may help to estimate the injury interval in forensic field.Conclusion:At the early phase of heart injuried by current,a large number of myofibre rupture, cytoplasm coagulating, homogeneous and eosinophilic changing; karyopyknosis, nuclear darkstaining, distortion, and partial nuclear strenching and vacuolization, chromatin margination; large number of crests fragmentation and dissolution, mitochondria vacuolization; partial myofilaments dissolution, etc. The patho;ogical change caused by electric force was not similar with that it was induced by acute myocardial infarction and other heart diseases and injury, and the result indicated that the pathological change was relatively characteristic and may be used to diagnose the injury induced by current. The fortis positive staining in carcoplasm also show the cardiac muscle be injuried by electric current.The expression of PEG-3 was related to nuclear damage, which increased in heart injury caused by current, but didn't increase in other myocardial injury and non-tumorous myocardial diseases. It may be a useful molecular index to diagnose heart injury induced by electric force. In additional, the rule of PEG-3 expression was changed following time, which may help to estimate the injury interval in forensic EI field. We can also discriminate the the electrouction group and the group of electrical shock after death, because there are only extremely tenuous positive staining for the group of electrical shock after death.
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