The Regenerated Observation Of Sciatic Nerve In Rats After Electrical Injury

objectives: To Utilize the model of electrical injury in rats'sciatic nerve, observed regularly the change of nerve and evaluated function of nerve after electical injury, which could provide a reference for treating the electrical injuried nerve on the best opportunity and methods. Method: Seventy-five adult healthy rats were divided into three groups(Groupâ… ,Groupâ…¡, Groupâ…¢),the weight of rat was limited in 220g-250g, the right sciatic nerve was injuried by three kinds of voltage, which were 50Hz 500v,1000v and 3600v,the harming time was one second. four rats in every group was selected at 1W,2W,4W,8W and 3m postoperatively, some of targets was observed, such as form of the injuried nerve,sciatic nerve function index,the motor nerve conduction velocity,the observation of histology and image analysis. Results: the limb's function of all rats disappeared after injury, the limb was red swelling which extincted gradually after two weeks. Rats of Groupâ…¡and Groupâ…¢ appeared toe ulcer after four weeks, which didn't recover in three months. the electrophysiological examination showed that MNCV of all rats vanished partly after injury, Groupâ… had recovered after eight weeks, the recover of nerve's MNCV and SFI in Groupâ…¡and Groupâ…¢ was slowly, there existed obviously indifference comparing to the normal after three months. The examination of histology shows that the marginal myelin sheath happened demyelination in Groupâ… ,the nerve of near end grew gradually toward to far end, the injuried nerve had no obviously difference comparing to the normal myelin sheath in sum,diameter and thickness after three months; a lot of myelin sheath happened disvolution in Groupâ…¡, there had obviously difference between the injuried nerve and the normal in myelin sheath's sum,diameter and thickness after three months; there was seriously ruin in internal structure of nerve in Groupâ…¢, the sum of regenerated myelin sheath was less at the far end and the diameter was smaller, there had greatly difference comparing to the normal. the fibroblast proliferate generously and grew into interal of nerve in both group, which lead to confusion in nerve's structure, the nerve's epineurium thicken, connective tissue proliferated generous at injuried place . Conclusion: 1). Electroparation damage leaded by the strong electric field was the main mechanism of electrical injury. The breakage of the blood- nerve barriers aggravated the nerve's damage. 2). The harmful extent in nerve was direct ratio tothe voltage at the same injuried conditions. 3). The injuried nerve by low voltage could repair by self which formed effective regeneration. 4). The injuried nerve by high voltage had regeneration but it couldn't form effective regeneration. 5). The injury by high voltage lead to ruin in nerve's surrounding organize and nerve's internal structure, which influenced nerve fiber's regeneration seriously.