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)

采用节段性谷氨酸灌注模型，观察了nNOS抑制剂7-硝基吲唑（7-NI）对短暂缺血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）：腹腔注射nNOS抑制剂7-NI（25 mg/kg），每2小时1次。B组（n=7）腹腔注射非选择性NOS抑制剂L-硝基精氨酸甲酯（L-NAME，25 mg/kg），每2 h 1次。C组动物（n=7）术前静脉注射AMPA/红藻氨酸受体拮抗剂NBQX（4.0mg/kg）; D组动物（n=7）术前口服利鲁唑（100 mg/kg/d），连续10天。E组（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3.9±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组动物的神经功能评分明显优于B组和E组（p<0.05）。E组脑片腹角灰质坏死严重。而A、C、D组则表现为轻度神经元改变伴嗜酸性粒细胞改变。7-NI对节段性谷氨酸灌注联合短暂缺血所致的脊髓损伤有保护作用。药物治疗nNOS抑制剂可能是ALS减轻脊髓谷氨酸神经毒性的一个有前途的策略

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