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

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Caaspase-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...

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

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(P<0.05).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(P<0.01,P<0.05) and the Caspase-3 expression was significantly decreased(P<0.01,P<0.05) 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.