OBJECTIVETo explore the acting mechanism of electrical field in electrical injury.

METHODSThirty-six New Zealand white rabbits were employed in the study and were randomly divided into 7 groups. There were 12 rabbits in group 1 and 4 in each group of other 6 groups. The animal model of nonthermal electrical injury previously replicated was employed in the study. Experiment with paralleled muscular fibers in electrical field was carried out in groups 2 approximately 4, while that of vertical muscular fibers in electrical field in groups 5-7. Anatomical examination was done to determine the index of deep burn injury (IDBI) in all groups of rabbits at 0, 2 and 24 postburn hour (PBH). Histological and ultrastructural examination, gamma picturing and isotope scanning with 99mTc were done in group 1 at 2 PBH.

RESULTSThere was no obvious skin injury in the white rabbits in group 1. Deep tissue necrosis was identified under the small electrode. Constant muscular spasm was observed in the inner side of the thigh. The muscles in paralleled electrical field suffered more severe injury than those in vertical one. Tissue injury was more severe in those areas with higher current density, less soft tissue, and also in the central area of the axis of the electric field. There were obvious changes in the perfusion and blood pool phases in these areas as observed with the aid of 99mTc. Light microscopic examination revealed swelling and necrosis of muscular fibers. Under electron microscopy, it was found that there were edema and dissolution with separation of lipid molecular layers of cell membrane, Shortened nucleus with partial dissolution of nuclear membrane, increased heparin granules within nucleus, swelling of mitochondria and endoplasmic reticulum, myofilament dissolution, expanded gap between myofilament and decreased number of heparin granules.

CONCLUSIONNon-thermal tissue injury in the electrical field, in terms of cell, ultrastructural and molecular levels, was induced and aggravated by all the factors constituting high voltage electrical field.