Establishment of soft-tissue-injury model of high-voltage electrical burn and observation of its pathological changes

A realistic model is very useful in laying the foundation for clinical treatment and further study of high-voltage electrical burns. We therefore established a soft-tissue-injury model of high-voltage electrical burn in rabbits using the highest voltage alternating current reported. Twenty-five healthy big-ear white rabbits were randomly divided into five groups (five in each group): control group (C group) before injury and 0.5-h, 24-h, 48-h and 72-h groups after injury. Except for the control group, the rabbits in the other four groups were anaesthetised with ketamine and the electrodes were placed in their left limbs. Electric shock was administered from a distance of 7 cm at 3000 V output voltage for 0.1s to observe the skin temperature, electric resistance, wound morphology, histological change and to measure the level of muscle viability and serum myocardial enzymes, among others. Instant current application reached 3-5A (mean: 4.1+/-0.8A), and electric shock voltage was fixed at 3000 V. The resistance between the two electrodes in the left limb decreased from between 1500 and 3600 Omega (mean: 2590.3+/-812.9 Omega) to 921.5+/-528.7 Omega after the electric shock. The skin temperature of the control group was 30.1+/-2.5 degrees C, which elevated to 50.3+/-4.5 degrees C after the electric shock. Muscle necrosis occurred progressively 24-72 h after the injury with obvious acute inflammation. Electron microscopic examination revealed a bilaminar sarolemma membrane structure, multiple mitochondria between muscle bundles and disappearance of shortened mitochondrial crista 48 h after injury. Additionally, the muscle viability index decreased gradually to 0.376+/-0.071 72 h after the injury, while in the control group it was 1.354+/-0.117. The skin, arterial walls, and peripheral nerves showed obvious degeneration and necrosis. Moreover, pathological changes were found in vital organs distal to the electric shock sites, such as the heart, liver, lung and kidney, indicating systemic injuries. The level of serum myocardial enzymes was significantly elevated, especially 24h after injury. Thus, electric shock at 3000 V output electric voltage for 0.1s can cause severe, focal, soft-tissue injury and pathological changes in the vital organs such as heart, liver, kidney and lung with the characteristics similar to those of high-voltage-electrical-burn patients.