An Experiemental Study On Electrocution Without Electrical Marks

BACKGROUND In the forensic practice, the cases of electrocution without current mark left are often happened. However, traditionally, the changes of morphology of electrocution are current mark and metallizing of skin, which were used to determine the electrocution. When there are no changes that can be observed by naked eyes, forensic pathologist were at wits' end and cannot infer whether electrocution exists. On the forensic pratice, the forensic pathologist must solve the three problems, i.e. whether did electrocution exist? Where were the exit and entrance of current? When did the electrocution exist, at antemortem or postmortem?Some studies indicated that cell membrane will be perforated in the electric field. However, in the electrocution, whether the cell membrane of the tissue of the victim are perforated? If perforated, whether the perforation only can be caused by electric field? At present, we cannot find reports in this field. Factually, eletric stimulus can cause the muscles constraction, and cause the length of sarcomere shortenning and some genes expression. Some studies indicated that in the experimental animals, the length of sarcomere shortenning and some genes expression only happened in the skeletal muscles that were stimulated, however, the other part did not. Thus, we study on the electrocution without current marks left depending on the experimental results. In the sudy, we try to find the answer for the above problems.PurposeThe study try to find the main points on forensic identification of the cases of electrocution without current marks left, including:ⅰ). To find the diagnosis index of the electrocution cases without current marks left;ⅱ). To find a way to infer the current pathway in the victim;ⅲ). To find the difference of electrocution from antemortem and postmortem.Methods1. The study on the morphological diagnosis index of the electrocution without current marks leftⅰ). The electrical perforation of blood cell in vitroBlood which has been donated by six volunteers(12ml blood was taken from each and devided six parts, each part is 2 ml blood). The sample was derided six groups, ie, control group, 5s, 10s, 20s, 30s and 1min electrified group. Each of electrified groups was electrified for 5s, 10s, 20s, 30s, 1min, respectively. Scanning electron microscope was used to detect the pores which caused by 220 voltage alternating current.ⅱ). The erythrocytes and endothelial cells of electrical and non-electrical rabbits, and those of victim from electrocution were observed by scanning electron microscope.Six animal models were set up. Model A, at first, right anterior limb and left hind limb of rabbits were soddened by 0.1M PBS; then, two pieces of wet gause which were soaked in the 0.1M PBS were winded on the right anterior limb and left hind limb of them, respectively, and then two hake wires were winded; finally, the two wires were connected to the alternating current of 220 voltage or 110 voltage, and electrified. Model B, two hake wires were fixed at the bilaterals of an oblong container, then a small quantities water were infunded into it, about 1.5cm deep, and then, one rabbit was put in each time; finally, the two wires were connected to the alternating current of 220 voltage or 110 voltage and electrified. Model C, the animals were were put into a bag and fallen from 40 meter high, one rabbit each time. Model D, Rabbits were burned to death by praying ethanol and burning it. Model E, Rabbits were intragastric administration with sodium nitrite, a blood poison, to death. Model F, Rabbits were put into a small container and carbon dioxide was imput to it, till they died. Forty-five rabbits were derided into nine groups randomly. Each group include five rabbits, i. e, control group, A1, A2, B1, B2, C, D, E, F group. Control group rabbits were killed by air injection from marginal vein of ear, A1 and A2 groups rabbits were electrified to death by model A, with 220 voltage and 110 voltage, respectively; and B1 and B2 groups rabbits were electrified to death by model B, with 220 voltage and 110 voltage, respectively. C～F group animals were killed by method described above. Erythrocyte and endothelium of aorta and pulmonary artery were observed by scanning electron microscope.Human endothelium of aorta and pulmonary artery of five cases that were electrified to death were observed by scanning electron microscope, and three cases caused death by other cause were observed too, as control group.Ⅱ. A study on current pathway in the electrocution rabbits——A study on expressions of il-6,hsp70,c-fos mRNA of skeletal muscle of rabbits which were electrified to deathTen New Zealand rabbits were divided into two groups, randomly, i.e experimental group and control group, each group include five rabbits. The experimental animal model were set up, that is, the left posterior limb and right anterior limb of experimental group were winded with gauze which were dipped in the 0.1M PBS, then 220V alternating current were electrocuted. The control group were sacrificed by air injection from marginal vein of ear. The quadriceps femoris and biceps brachii were applied to detect the level of i1-6,hsp70,c-fos mRNA with the technique of fluorescent quantitation RT-PCR, the cycle threshold value were analysed by software of SPSS 10.0.Ⅲ. A study on the distinguishment of electrocution from antemortem or postmortemⅰ). A study on the expressions differientation of hsp70,c-los,i1-6mRNA in skeletal muscles and the cardiac muscle of rabbits electrified antemortem and postmortemFifteen New Zealand rabbits were divided into three groups randomly, i.e, antemortem electrocution group, postmortem electrocution group, and control group, each group include five rabbits. For the antemortem electrocution group, the left posterior limb and right anterior limb of rabbits were winded with gauze which were dipped in the 0.1M PBS, then electrocuted by 220V alternating current. However, to the postmortem electrocution group, animals were sacrificed by air injection via marginal vein of ear at first, then the left posterior limb and right anterior limb as experimental group were winded with gauze which were dipped in 0.1M PBS, then electrocuted by 220V alternating current, immediately. The control group were sacrificed by air injection via the vein of edge of ear, too, without electrocution. 50 mg of quadriceps femoris and biceps brachii were applied to detect the level of IL-6,hsp70,c-fos mRNA With the technic of fluorescent quantitation RT-PCR, the cycle threshold value were analysed by software of SPSS 11.5.ⅱ). A study on the length change of sarcomere of rabbits electrified to death at antmortem and postmortemTwelve rabbits were randomly divided into four groups, each group include three rabbits: ControlⅠgroup, controlⅡgroup, electrocution group, and electrified group after death. ControlⅠ,Ⅱ, and the rabbits electrified group after death were killed by air injection via marginal vein of ear. In controlⅠgroup, quadriceps femoris of left hind limb were taken immediately and put in 3％glutaral solution(V/V)and fixed for 24h. In controlⅡgroup, the skeletal muscle were taken after 24h when sacrificed and put in 3％glutaral solution(V/V) and fixed for 24h. Electrocution group rabbits were electrified to death by 220 voltage, whose right anterior limb and left hind limb of rabbits were soddened by 0.1M PBS; then, two pieces of wet gause which were soaked in 0.1M PBS were winded on the right anterior limb and left hind limb of them respectively, and then two wires were winded; finally, the two wires were connected to the alternating current of 220 voltage and electrified to death. In electrified group after death, when the rabbits were killed by air embolism, they were electridied by 220 voltage alternating current, too. Then, their quadriceps femoris of left hind limb were taken out and put in 3％glutaral solution(V/V). Transmission electron microscope were used to observe the sarcomere, and the length of sarcomere were measured and the results were analysed by statistics.Results1. The study on the morphological diagnosis index of the electrocution without current leftⅰ). the electrical perforation of blood cell in vitroPores can be detected on erythrocytes and leukocytes which have been electrified in all electrified groups. Pores shape is round or ellipase. Pores on the erythrocyte may be one or more, however, the pores on the leukocyte maybe more than one and looked like cribble. Amounts of cells which have been perforated increased with time going on of electrification.ⅱ) The erythrocytes and endothelial cells of rabbits that were electrified to death and non-electric shock death and human erythrocytes and endothelial cells from the victim of electrocutin by scanning electron microscope.We find that some pores can only be seen on the surface of erythrocytes and endothelial cells of aorta and pulmonary artery of those died of electrifying, however, there are no pores were found on those of the non-electrifying and normal control animals.Some pores can only be seen on the surface of endothelial cells of aorta and pulmonary artery of those died of electrocution, however, there are no pores were found on those died of other cause.Ⅱ. A study on current pathway in the electrocuted rabbits A study on expressions of IL-6,hsp70,c-fos mRNA of skeletal muscle of rabbits that were electrified to deathWhen the rabbits were executed electrocution, the skeletal muscles would constract, and the i1-6,hsp70,c-fos genes will express significantly at the level of transcription, compared with the non-electrified limbs.Ⅲ. A study on the difference of electrocution from antemortem and postmortemⅰ). A study on the expressions differientation of hsp70,c-fos,i1-6mRNA in skeletal muscles and the cardiac muscle of rabbits electrified at antemortem and postmortemThe level of i1-6,hsp70,c-fos mRNA in the skeletal muscle and cardic muscle of the rabbits that were electrified to death by alternating current increased significantly. However, those of postmortem group only slightly increased. the extent of the former is far more than the latter, P＜0.05. ⅱ). A study on the length change of sarcomere of rabbits electrified to death antmortem and postmortemThe lengthen of the sarcomere in both electrocution group and electridied after death group were shortened, however, the extent of the former is far more than the latter, P＜0.05. The length of sarcomere in controlⅡgroup was lengthened noticeablely, P＜0.05.Conclusionⅰ). Alternating current can cause the cell perforating in vitro.ⅱ). Alterning current can cause rabbits' blood vessel endothelium perforating in vivo, and the perforation is specific relatively to electric field and current.ⅲ) Alterning current can cause human blood vessel endothelium perforating in vivo. Therefore, the perforation phenomena may be supposed to diagnose the electrified death cases where no electric mark is left.ⅳ). The expressions disparation of IL-6,hsp70,c-fosmRNA on the electrified rabbits symmetrical skeletal muscle can be an index to estimate the current pathway.ⅴ). The expressions disparation of IL-6,hsp70,c-fosmRNA and the length changes of sarcomere of the skeletal muscle could be suggested as an index to ditinguish electrocution at antemortem from postmortem.