银杏叶提取物EGb761对大鼠脊髓损伤后的神经保护作用

Neuro-protective effect of Ginkgo biloba extract EGb761 on spinal cord injury in rats

目的探讨银杏叶提取物EGb761对实验性大鼠脊髓损伤后神经保护的作用及其机制。方法成年雄性SD大鼠132只,体重200～250 g,随机分为正常对照组（N组）、损伤组（T组）、甲基强的松龙治疗组（MP组）和EGb761治疗组（EGb761组）,每组33只。T组、MP组、EGb761组用改良Allen法以25GCF损伤力度致伤大鼠,建立T9脊髓中度损伤模型。术后4、8、24 h每组随机取3只动物切取损伤区1 cm脊髓节段,分别用黄嘌呤氧化酶法和硫代巴比妥酸（TBA）法测定脊髓组织中超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量。分别于术后24 h、3、5、7、14 d处死动物（n=6）,快速取T9节段脊髓,TUNEL法标记细胞凋亡,免疫组化方法检测诱生型一氧化氮合酶（iNOS）的表达。结果术后4、8、24 h EGb761治疗组SOD活性及MDA含量与损伤对照组比较均差异有显著性（P〈0.01）。术后各时相点EGb761治疗组神经细胞凋亡指数和iNOS表达阳性细胞率均低于损伤对照组（P〈0.01或P〈0.05）。结论 EGb761能抑制脊髓损伤后的脂质过氧化反应,减轻神经细胞的凋亡,其机制可能与抑制iNOS表达有关。

Aim To investigate neuro-protective effect of Ginkgo biloba extract EGb761 on spinal cord injury in rats.Methods 132 SD rats were randomly divided into sham group,injury control group,methylprednisolone（MP） treated group and EGb761 treated group,33 rats for each group.The spinal cord injury model was established by modified Allen method.After 4h,8h,24h superoxide dismutase（SOD） activity and malondialdehyde（MDA） in 1cm segment of the spinal cord taken from 3 rats in each group randomly were deter-mined by xanthine oxidase and thiobarbituric acid（TBA） respectively.Rats were killed（n = 6） 24 h,3 d,5 d,7 d,14 d after treat-ment and T 9 spinal cord segment was quickly taken.Apoptosis was labeled by TUNEL method and inducible nitric oxide synthase（iN-OS） expression was detected by immunohistochemistry.Results EGb761 treated group and injury control group were significantly dif-ferent in SOD activity and MDA content after 4,8,24 h（P〈 0.01）.Compared to the injury control group,apoptosis index of neuro-cytes and the expression of iNOS positive cells both decreased obviously（P 〈0.01 or P〈 0.05） at various time points after treatment in EGb761 treated group.Conclusion EGb761 can inhibit lipid peroxidation and reduce the apoptosis of neurocytes after spinal cord in-jury in rats.Its mechanism maybe explained by that EGb761 can inhibit the expression of iNOS.