Assessment of the protective effect of nNOS inhibitor, 7-nitmindasole(7-NI) on spinal cord neurons using glutamate segmental infusion model.-Development of pharmacologic spinal cord protection for amyotrophic lateral sclerosis(ALS)

采用短缺血脑段性谷氨酸输注模型，观察nNOS抑制剂7-硝基吲达索（7-NI）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组动物（n=7）每2 h腹腔注射nNOS抑制剂7- ni （25mg/kg）预处理。B组动物（n=7）每2 h腹腔注射非选择性NOS抑制剂n (G)-硝基- l -精氨酸甲酯（L-NAME, 25mg/kg）预处理。C组动物（n=7）预处理后静脉给予AMPA/kainate受体拮抗剂NBQX (4.0 mg/kg)，与A组相似。D组动物（n=7）术前口服利鲁唑（100mg/kg/ D） 10 D。E组（n=7）只接受灌胃，作为a组的对照。动物以2ml/min的速度注射谷氨酸（30 mM），灌胃6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3.9±0.7，B组为1.9±0.7，C组为3.6±1.1，D组为4.1±0.4，E组为0.9±0.7。A组动物神经功能评分显著高于B组和E组（p<0.05）。E组切片显示腹角严重灰质坏死。A组、C组和D组均表现为轻度神经元改变，伴嗜酸性改变。7-NI可能对段性谷氨酸输注合并短暂缺血所致的脊髓损伤有保护作用。在药理学上，使用nNOS抑制剂治疗ALS可能是一种有希望的策略，可以减少脊髓中有害的谷氨酸神经毒性

We evaluated the protective effects of nNOS inhibitor, 7-nitroindasole(7-NI) on spinal cord neurons using segmental glutamate infusion model under brief ischemia in vivo. New Zealand white rabbits underwent an infrarenal aortic isolation. Group A animals(n=7) received intraperitoneal pretreatment of nNOS inhibitor, 7-NI(25mg/kg) every two hours. Group B animals(n=7) received intraperitoneal pretreatment of non-selective NOS inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME, 25mg/kg) every two hours. Group C animals (n=7) received intravenous administration of AMPA/kainate receptor antagonist, NBQX (4.0 mg/kg) after the pretreatment similar to group A Group D animals(n=7) received oral medication of riluzole(100mg/kg/day) preoperatively for ten days. Group E(n=7) received viehcles only as a control of group A. Animals received segmental glutamate(30 mM) infusion for 6 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 3.9±0.7 in group A, 1.9±0.7 in group B, 3.6±1.1 in group C, 4.1±0.4 in group D and 0.9±0.7 in group E respectively. Animals in group A showed significantly better neurologic score compared with group B and group E (p<0.05). Sections from group E exhibited severe gray matter necrosis in ventral horn. In contrast, group A, group C and group D exhibited mild neuronal change with eosinophilic changes. 7-NI might have protective effects ~on spinal cord injury induced by segmental glutamate infusion combined with brief ischemia. Pharmacologic, therapy with nNOS inhibitor might be a promising strategy for ALS reducing the detrimental glutamate neurotoxicity in the spinal cord