大剂量维生素C联合小剂量甲基强的松龙对脊髓损伤后脊髓病理生理变化的影响

目的]探讨脊髓受压及减压后,大剂量维生素C(vitaminC)联合小剂量甲基强的松龙(MP)对脊髓灰质血流量,体感诱发电位(SEP),组织学变化,运动功能的影响.方法]36只犬随机分为3组,每组12只.A组于SEP消失后5min静脉注射MP 30 mg/kg,以5.4 mg (kg·h)输液泵静脉注射；B组于SEP消失后5min以同样方式注射vitaminC 200 mg/kg+ MP 10 mg/kg,减压后12 h,24h各注射vitaminC 200 mg/kg；C组于SEP消失后5min静脉注射0.9％氯化钠,同样以5.4 mg(kg·h)输液泵静脉注射.均持续90 min后减压,期间检测SEP及脊髓灰质血流量,减压后3h重复检测,并进行改良Tarlov评分.减压后28 d通过病理组织学分析确定损伤的范围.结果]在持续压迫期间A组4只犬出现了SEP,B组5只犬出现了SEP,C组无一出现.减压后A组有2只犬出现SEP,B组有2只犬出现SEP,C组有1只犬出现SEP.三组犬中出现SEP的脊髓灰质血流量明显高于没有出现SEP的犬(P＜0.05).A、B组脊髓灰质血流量明显高于C组(P＜0.05).A、B组动物后肢的运动功能可以较快恢复,C组不能恢复.A、B组脊髓损伤范围与C组具有显著性差异,病理改变与SEP及脊髓血流量具有相关性,与运动功能的恢复具有相关性.结论]大剂量维生素C与小剂量甲基强的松龙联合应用在神经功能保护及恢复方面提供了显著持续的作用,可能增加了脊髓局部的血流量.维生素C可以部分替代甲基强的松龙对于脊髓损伤的作用.

Effect of high-dose vitamin C combined with low-dose methylprednisolone on pathology and physiology after spinal cord injury

Objective] To examine the effect of high-dose vitamin C combined with low-dose methylprednisolone on regional spinal cord blood flow,electrophysiological function,histopathological changes and motor functinnal recovery.Method] Thirty-six canine were divided into three groups,with twelve in each group.Group A:methylprednisolone(30 mg/kg intravenous loading dose followed by 5.4 mg/kg/h intravenous infusion),Group B:vitamin C(200 mg/kg+MP(10 mg/kg)and Group C: saline solution administered to thirty-six beagles(twelve in each group).Somatosensory evoked potentials and spinal cord blood flow were evaluated throughout the period of sustained compression and at three hours after decompression.Functional motor recovery was evaluated after decompression.The volume of the lesion and damage to the tissue were assessed with histological analysis 28 days after decompression.Result]Four dogs in group A and five dogs in group B and none in group C recovered measurable somatosensory evoked potentials during sustained compression.After decompression,two more dogs in group A and three more dogs in group B and one dog in group C recovered somatosensory evoked potentials.In the three groups,spinal cord blood flow was significantly higher(P<0.05) in the dogs that had recovered somatosensory evoked potentials than it was in the dogs that had not.Motor tests demonstrated rapid recovery of hindlimb motor function in the groups A and B,significantly better than in the group C.Conclusion]The high-dose vitamin C combined with low-dose methylprednisolone administered in this study provide a large or significant lasting benefit with regard to neurological preservation or restoration.Methylprednisolone may increase regional spinal cord blood flow.Vitamin C can replace part of methylprednisolone in treatment of spinal cord injury.