The Protective Effects Of Edaravone On The Replanted Limb Of Rats

Objective:In order to study the protective effects of Edaravone on the replanted limb of rats, a model of limb replantation was established. By detecting the effects of Edaravone to serum Superoxidedismutase (SOD), Malondialdehyde (MDA), activity of Na+-K+-ATPase and Ca2+-ATPase of mitochondrion in skeletal muscle, and the structural changes of skeletal muscle was observed with optical microscope and electron microscope.Methods:Forty female Sprague-Dawley (SD) rats were randomly divided into four groups of ten rats each. Sham group (S), model group (M), low concentration of edaravone group (E1), high concentration of edaravone group (E2). M group was the model of limb replantation of rats. The rats were fixed following anesthetized. After the right posterior limb was disinfected, along the longitudinal direction on femoral vessels cut skin, the femoral artery, vein and nerve were exposed and dissociated. Blunt separation layers of organizations, in middle level of right femur cut off all muscles, only preserve vessels. After the blood was drove, the femoral artery and femoral vein were occluded by vascular clamp. The right posterior limb was put in the room temperature for 3h, then the vascular clamp was removed for reperfusion, suture the muscle, nerve and skin. The operative field was covered with saline soaked sterile gauze. Each group was given heparin sodium 1000U/kg to heparinization via the caudal vein before reperfusion. The rats in group E1 and E2 not only received the operation mentioned above, but also injected edaravone respectively with the concentration of 0.5mg/kg and lmg/kg via the caudal vein before reperfusion. The same volume of saline was injected in group S and M. In group S, the right posterior limb only dissociates the femoral artery and vein, put in the room temperature for 3h, then suture the skin. At the time 5h and 24h reperfusion,1 ml blood of each rat was taken via the external jugular vein. Serum Superoxidedismutase (SOD) and Malondialdehyde (MDA) were determined. At 24h take the right posterior limb gastrocnemius, extract mitochondrial to determine the changes of Na+-K+-ATPase and Ca2+-ATPase. Take the right posterior limb tibial muscle to detect the structural changes of skeletal muscle with optical microscope and electron microscope.Results:40 healthy SD rats included in the experiment entered the final analysis.1 The general morphological observation:In group S, right posterior limb muscle and skin ruddy and warm. In the group M, the color of right posterior limb muscle and skin was slightly dark red, and the temperature was slightly lower. In group E1, the appearance of the right posterior limb was alleviative to group M. The appearance in group E2 was more alleviative than group M.2 For the histological section:In group S, the muscular fiber was normal, there was no edema in the interstitial, and there was no inflammatory cells infiltration. In group M, the muscular fiber was chaotic and ruptured. The blood vessel was dilated and congestive. The interstitial was edema, and there was infiltration with many inflammatory cells. In group E1, the muscular fiber and interstitial were slightly edema. There was inflammatory cell infiltration. In group E2, the interstitial was slightly edema, and there were scattered inflammatory cells infiltrate.3 Observations from transmission electron microscope:The arrangement of myofibril in group S was relatively regular. Z line was clear, mitochondrial crista was compact, membrane was intact and without swelling. Parts of myofibril in group M were broken. Z line was unclear or disappeared, mitochondria were highly swollen and mitochondrial crista was in chaos, and parts had been vacuoles. In group E1, the arrangement of myofibril was relatively regular. Z line was a little obscured. There have major lipid droplets. Parts of the mitochondria were vacuolated. In group E2, the arrangement of myofibril was relatively regular. Z line was clear. There have small amounts of lipid droplets. Parts of the mitochondria were vacuolated.4 The activity of SOD and the content of MDA in serum: Serum SOD activity:Activity of SOD in group M, E1 and E2 was lower than group S (p＜0.05). The activity of SOD in group E1 and E2 was higher than group M (p＜0.05). The activity of SOD in group E2 was higher than group E1 (p＜0.05). The activity of SOD at 24h of reperfusion in group M, E1 and E2 was lower than 5h.Serum MDA content:Content of MDA in group M, E1 and E2 was higher than group S (p＜0.05). The content of MDA in group E1 and E2 was lower than group M (p＜0.05). The content of MDA in group E2 was lower than group E1 (p＜0.05). The content of MDA at 24h of reperfusion in group M, E1 and E2 was higher than 5h.There was no significant difference of SOD and MDA at 24h of reperfusion compared with that 5h in group S (p>0.05).5 Activity of mitochondria Na+-K+-ATPase and Ca2+-ATPase:The activity of Na+-K+-ATPase and Ca2+-ATPase in group M, E1 and E2 was lower than group S (p＜0.05). The activity of Na+-K+-ATPase and Ca2+-ATPase in group E1 and E2 was higher than group M (p<0.05). The activity of Na+-K+-ATPase and Ca2+-ATPase in group E2 was higher than group E1 (p＜0.05).Conclusion:1 Edaravone can reduce ischemia reperfusion injury of rats, have the protective effect on replanted limb.2 The mechanism may be increased in the activity of SOD, mitochondria Na+-K+-ATPase and Ca2+-ATPase, decreased the content of MDA.