Pharmacologic evaluation of protective efficacy of caspase inhibitor, diazoxide for spinal cord protection using aspartate segmental infusion model. -Strategy against paraplegia by reducing mitochondrial-dependent apoptotic pathway

采用在体脊髓短暂缺血模型，观察了半胱氨酸蛋白酶抑制剂二氮嗪对脊髓神经元的保护作用。新西兰白色家兔接受肾下主动脉隔离。A组（n=7）：静脉注射caspase抑制剂二氮嗪（4 mg/kg）; B组（n=7）在预处理后给予NMDA受体拮抗剂MK-801（6 mg/kg）。C组动物（n=7）术前口服利鲁唑（100 mg/kg/天）10天，增加与A组相似的预处理。D组动物（n=7）仅接受Viehcles作为A组的对照。术后12、24、48 h采用Tarlov评分法对动物神经功能状态进行评分。神经功能评分A组为3.8±0.9，B组为3.4±0.6，C组为4.0±0.6，D组为0.8±0.6。与D组相比，A组动物显示出显著更好的神经功能恢复（p<0.05）。A组、B组和C组的功能评分无显著性差异。D组的切片显示腹角有严重的灰质坏死。而A、B、C组则表现为轻度神经元改变伴嗜酸性粒细胞改变。二氮嗪可改善节段性门冬氨酸灌注联合短暂缺血所致的脊髓损伤。使用半胱天冬酶抑制剂的药理学策略可能是治疗与主动脉手术相关的迟发性截瘫的有希望的策略，减少天冬氨酸兴奋毒性。

We evaluated the protective effects of caspase inhibitor, diazoxide on spinal cord neurons using segmental aspartate infusion model under brief ischemia in vivo. New Zealand white rabbits underwent an infrarenal aortic isolation. Group A animals(n=7) received intravenous pretreatment of caspase inhibitor, diazoxide (4mg/kg). Group B animals(n=7) received pretreatment of NMDA antagonist, MK-801(6mg/kg) after the pretreatment similar to group A. Group C animals (n=7) received oral medication of riluzole(100mg/kg/day) preoperatively for ten days adding the pretreatment similar to group A. Group D animals(n=7) received viehcles only as a control of group A. Animals received segmental aspartate(30 mM) infusion for 10 minutes at a rate of 2ml/min. Neurologic status was scored at 12,24 and 48 hours after surgery using Tarlov score. Neurologic status was 3.8±0.9 in group A, 3.4±0.6 in group B, 4.0±0.6 in group C, 0.8±0.6 in group D respectively. Animals in group A showed significantly better neurologic recovery compared with group D (p<0.05). There was no significant difference between the functional scores of group A, group Band groupC respectively. Sections from group D exhibited severe gray matter necrosis in ventral horn. In contrast, group A, group B and group C exhibited mild neuronal change with eosinophilic changes. Diazoxide might ameliorate the spinal cord injury induced by segmental aspartate infusion combined with brief ischemia. Pharmacologic strategy using caspase inhibitor, might be a promising strategy against delayed onset paraplegia associated with aortic surgery reducing aspartate excitotoxicity.