内毒素预处理激活大鼠急性脊髓损伤Nrf2蛋白抑制Caspase-3的表达  

Nrf2 protein activated by LPS pretreatment inhibits Caspase-3 expression in rats after acute spinal cord injury

作　　者：李维朝[1] 蒋电明[1] 朱凤臣[1] 祁小桐[1] 黄英如[2] 

机构地区：[1]重庆医科大学附属第一医院骨科,重庆400016 [2]重庆医科大学中医药学院骨科教研室,重庆401331

出　　处：《第三军医大学学报》2011年第19期2029-2033,共5页Journal of Third Military Medical University

摘　　要：目的研究大鼠急性脊髓损伤及经内毒素预处理后损伤脊髓中转录因子Nrf2及凋亡蛋白Caspase-3的表达。方法 SD大鼠132只,随机数字表法分为假手术组、模型组和LPS预处理组。采用改良Allen’s打击法制作SD大鼠急性脊髓损伤(acute spinal cord injury,ASCI)模型,在术后1、3、5、7 d进行BBB(basso beattie and bresnahan)评分。在建模后6、12 h、1、3、5、7 d获取损伤段脊髓标本,HE染色观察其组织病理学变化;Nissl染色观察神经元中尼氏小体的变化;免疫组织化学染色定位观察损伤段脊髓中Nrf2和Caspase-3的表达变化规律;Western blot法分析损伤段脊髓中Nrf2表达的变化规律。结果模型组和预处理组术后1、3 d大鼠BBB评分都有明显降低,5、7 d时预处理组BBB评分高于模型组(P<0.05)。6、12、24 h时HE和Nissl染色显示模型组和预处理组脊髓有广泛性出血,大量红细胞渗出,间质性水肿严重,核固缩,神经元数目明显减少,细胞体积变小,尼氏体模糊、碎裂。假手术组大鼠脊髓组织低表达Nrf2及微量表达Caspase-3。3、5、7 d时,与模型组相比,预处理组形态学损伤明显减轻,Nrf2蛋白表达明显增强(P<0.01,P<0.05),凋亡蛋白Caspase-3表达明显降低(P<0.01,P<0.05)。结论内毒素预处理大鼠在SCI后Nrf2蛋白表达明显增加,抑制凋亡信号Caspase-3的表达,减轻神经元的死亡与损伤,其可能与SCI的病理改变与转归密切相关。Objective To study the Nrf2 and Caspase-3 expressions in rats with LPS pretreatment after acute spinal cord injury（ASCI）.Methods One hundred and thirty-two SD rats were randomly divided into a sham group,a model group and a LPS-pretreatment group.The model of ASCI was built by the modified Allen＇s method,and was assessed by the Basso Beattie and Bresnahan（BBB） score at 1,3,5 and 7 d after the operation.The injured spinal cord tissue samples were collected at 6,12 h,and 1,3,5 and 7 d after the operation.The pathological changes of rat spinal cord were observed by HE staining,the Nissl body in neurons was observed by Nissl staining,the expressions of Nrf2 and Caspase-3 were detected by immunohistochemical staining,and the Nrf2 protein level was detected by Western blotting.Results The rat BBB scale decreased significantly in both the model group and the LPS-pretreatment group at 1 d and 3 d after operation and was higher in the LPS-pretreatment group than in the model group at 5 d and 7 d after operation（P0.05）.The injured spinal cord by HE and Nissl staining showed an extensive focal hemorrhage,large quantity of erythrocyte diapedesis,severe interstitial edema,karyopyknosis,significantly decreased number of neurons,small cell volume and blurring and debris of Nissl bodies in the model group and the LPS-pretreatment group at 6 h,12 h and 1 d after operation.Low Nrf2 and trace Caspase-3 expressions were detected in the sham group.As compared with those of the model group,the morphological injury was significantly alleviated,the Nrf2 protein expression was significantly enhanced（P0.01,P0.05） and the Caspase-3 expression was significantly decreased（P0.01,P0.05） in the LPS-pretreatment group at 3 d,5 d and 7 d after operation.Conclusion The Nrf2 expression is significantly increased in rats with LPS pretreatment after ASCI.Nrf2 inhibits the Caspase-3 expression and reduces the neuronal death and injury,which may be closely related to the pathological changes and prognosis of ASCI.

关 键 词：内毒素 急性脊髓损伤 预处理 Nrf2蛋白 半胱氨酸蛋白酶-3 

分 类 号：R651.2[医药卫生—外科学] R363.22[医药卫生—临床医学]