纳络酮早期干预对大鼠弥漫性轴索损伤后延髓髓鞘的作用观察

Effects of naloxone on acute diffuse axonal injury in rats

目的观察纳络酮(Naloxone)干预对弥漫性轴索损伤(diffuse axonal injury,DAI)病理损害的影响。方法采用改良的Marmarou大鼠颅脑DAI模型。Wistar雄性大鼠(99只),随机分为对照(假损伤)、损伤、纳络酮干预(2mg/kg于伤后45分腹腔一次性注射)3个组,于伤后2、6、24、72小时作行为学评分并观察病理形态学变化。结果大鼠DAI后神经功能障碍即时发生,干预组与损伤组比较,6小时及24小时评分有显著差异(P<0.05)。神经纤维嗜银染色切片光镜下见,损伤组24小时病理损害程度最重,延髓纤维排列紊乱,回缩球大量形成,干预组中轴突走行较正常,回缩球密度小。电镜观察可见损伤组24小时延髓髓鞘板层明显分离甚或轴索断裂,干预组轴索断裂少见。结论早期、大剂量纳络酮干预可减轻大鼠DAI后延髓髓鞘继发性病理损害。

Objective To observe the effects of the naloxone on the pathological damage of the acute diffuse axonal injury（DAI） in rats.Methods A total of 99 male Wistar rats were randomly divided into control group（sham injury）,injury group and naloxone intervention group（2.0 mg/kg of naloxone were administered intraperitoneally 45 minutes after trauma）.The DAI models were made by modified Marmarou＇ method（impact-acceleration model）.The neurological scores were estimated and pathological changes were observed at various times after cerebral injury in rats（2,6,24 and 72 hours）.Results The severest neurological dysfunction occurred immediately in rats after DAI.The neurological scores of interventional group were significantly improved at 6 hours and 24 hours,compared with those of injury group（P〈0.05）.The worst degree of pathological damage was seen at 24 hours by Glees.The light microscopy showed severe derangement of medullary fibers and large numbers of formation of retraction balls in injury group at this time point,but relatively normal fiber arrangements and low-density retraction balls in the naloxone intervention group at the same time point.Obvious separation of myelin layer and axonotmesis were observed in injury group,but rare axonotmesis in naloxone intervention group.Conclusion Early use of high dose of naloxone may provide remarkable protection against the experimental DAI in the early stage.