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

本研究采用短缺血脊髓段性天冬氨酸输注模型，评价了caspase抑制剂二氮氧化物对脊髓神经元的保护作用。对新西兰大白兔进行了肾下主动脉分离。A组（n=7）给予半胱天冬酶抑制剂二氮唑（4mg/kg）静脉预处理。B组（n=7）预处理后给予NMDA拮抗剂MK-801（6mg/kg）预处理，与a组相似。C组（n=7）术前给予利鲁唑（100mg/kg/ D）口服10天，并在此基础上加用与a组相似的预处理。D组（n=7）仅作为a组的对照，给予天冬氨酸（30mm）以2ml/min的速率静脉滴注10分钟。分别于术后12、24、48小时用Tarlov评分进行神经状态评分。A组神经功能评分为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。A组动物神经功能恢复明显优于D组（p<0.05）。A组与组间功能评分差异无统计学意义。D组切片显示腹角严重灰质坏死。相比之下，A、B、C组表现为轻度神经元改变，伴嗜酸性改变。二氮氧化合物可改善段性天冬氨酸灌注合并短暂缺血所致的脊髓损伤。使用caspase抑制剂的药理学策略，可能是一种有希望的策略，用于治疗主动脉手术相关的延迟性截瘫，降低天冬氨酸的兴奋毒性。

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.