动物模型 z-bo 2020-08-10 563

　　Human electric injuries are mostly high-voltage electric burns as serious. High-voltage electrical injuries are not only different in the nature and scope of local wounds from general burns, but also have a certain degree of complexity in judging the condition and handling and repairing local wounds after injury.

　　(1) Copy method: Remove the coat of the inner thigh of the experimental rabbit's hindlimbs about 6cm×8cm. Place copper electrode plates (3cm×3cm) on both sides of the site and fix it. The right side is the inlet and the left is the outlet. The electric shock was given under non-anaesthesia. The electric shock time was 5s, the rated voltage was 10kV, the actual passing current was (2±0.15)A, and the skin resistance was 2500Ω. The electrode plate was quickly released after the electric shock.

　　(2) Model features Appearance inspection: After the electrode plate is removed, the local skin is compared with the surrounding uncontacted surface: it is harder and the boundary is clear. The outer periphery is a narrow black ring, slightly higher than the edge, and there are 1 to 2 hoe carbonization centers. Near the center is gray and tough necrotic skin, slightly concave. Cut the skin, touch the muscles to be slightly swollen, the color is uneven, gray and red, the tissue is loose, easy to tear, and lack of elasticity. Embolism of small blood vessels can be seen in this layer, deep muscles are slightly dark red, and coagulation can be seen locally. The extent of muscle damage is unclear. From 4 to 28 hours after injury, the boundary of the burn area on the outer skin becomes more obvious; the entire wound is gray-white, but the exudation is not obvious; the local swelling is increased, and the texture is hard and leather-like. Secondary embolism or coagulation of larger blood vessels occurs. The scope of tissue necrosis gradually expanded, and the whole muscle was damaged, especially the deep tissue necrosis gradually formed. Normal muscle fibers, inter-ecological tissue, and flaky muscle coagulation necrosis coexist. 5-7 days after the injury, the skin was ulcerated, the muscles turned over, the local swelling was gradually reduced, the wound was foul-smelling, the infection was severe, and pus was discharged, and the inflammatory infiltration involved the original normal area. The wound becomes dark gray or dark red bleeding spots appear, the skin is deliquescence, and the degree of exfoliation of the burned tissue increases. Erosion occurred in deep tissues, and obvious vascular embolism was seen. Nerves and tendons are exposed. The normal rabbit skin is shiny and smooth, the muscle bundles are arranged regularly, the color is uniform, and the blood vessel direction is clearly visible.

　　Light microscopic examination showed that the skin showed hyaline change in the early stage of electric burn, subcutaneous coagulation necrosis, interstitial hyperemia, edema, blurred muscle fiber structure, and fusion of muscle filaments into clumps or vacuoles. 24 to 48 hours after injury, there was extensive purulent necrosis of the superficial dermis. The deep tissues showed homogeneous changes with infiltration of inflammatory cells. Vascular congestion is obvious, most of the small arteries and veins have bleeding, most of the muscle fibers near the lesion are coagulated and dissolved, and there is obvious congestion, congestion, and neurodegeneration in the muscle. 3 to 5 days after the injury, epidermal necrosis and ulcer formation, a large amount of suppuration under the dermis, thrombosis in the blood vessel wall, necrosis of some arteries, interstitial congestion and bleeding, and disintegration of some nerve cords. Muscle fibers have focal scars, partially dissolved, large areas of necrosis in the central area, and individual fatty changes and vacuoles. After 7 days, a large number of granulation tissues were obviously repaired. Normal section findings: the skin structure is complete, the muscle fibers are arranged neatly, the nucleus is normal, and there is no vascular congestion.

　　(3) Comparative Medicine Although progressive necrosis also occurs in thermal burns, it is difficult to explain some common clinical phenomena such as progressive and sandwich-like necrosis of electrical injury tissues with the theory and practice of thermal injury. Most of the electrical burns seen in clinical practice are electrical burns above 10,000V. In the experiment, the burns caused by arcs are avoided, so that the nature of the local damage after the electric shock is electrical contact burns instead of arc burns, and it is basically close to Electric burn caused by careless operation on the daily system line. The burn condition of the local wound after electric burn is basically the same as that of high voltage electric burn in clinic, and the development of the wound is also similar. This shows that the use of the high-voltage electric discharge device for animal experiments can basically reflect the situation of clinical electric burns.