Nrf2和HO-1在实验性自身免疫性脑脊髓炎大鼠脊髓中的动态表达及依达拉奉保护机制的研究

The dynamic expression of Nrf2 and HO-1 in spinal cord tissues of experimental autoimmune encephalomyelitis of rats and the mechanism underlying neuroprotective effect of edaravone

目的:探讨依达拉奉对实验性自身免疫性脑脊髓炎(Experimental autoimmuneen cephalomyelitis,EAE)大鼠的影响及作用机制。方法:应用豚鼠脊髓匀浆抗原(GPSCH)免疫Wistar大鼠建立EAE模型,随机分为对照组、EAE组、依达拉奉小剂量组、依达拉奉大剂量组及地塞米松组(DXM),比较各组不同时间点的发病率并进行神经功能评分,脊髓组织切片进行HE染色、三色染色观察病理变化,免疫组化染色观察Nrf2及血红素加氧酶(HO-1)表达。结果:依达拉奉大剂量组(8.33%)和DXM组(0%)的发病率均低于EAE组(58.3%)(P<0.05);在发病高峰期时,依达拉奉大剂量组(0.32±1.10)、DXM组(0)各大鼠神经功能评分明显低于EAE组(2.06±2.01)及依达拉奉小剂量组(1.21±1.51)(P<0.05);依达拉奉大剂量组(1.25±1.67)、DXM组(0)大鼠16天时脊髓组织内炎症细胞浸润形成的血管袖套数目明显低于EAE组(8.17±3.49)及依达拉奉小剂量组(7.67±4.37)(P<0.05);依达拉奉大剂量组的轴突及髓鞘损伤程度较EAE组和依达拉奉小剂量组轻;与正常组比较,EAE组、依达拉奉小剂量组、依达拉奉大剂量组及DXM组大鼠的脊髓组织中Nrf2及HO-1表达均上调,依达拉奉大剂量组的表达数目最高,且与其他组比较差异具有统计学意义(P<0.05)。结论:依达拉奉可以降低EAE大鼠的发病率,减轻发病时神经功能损伤的程度以及脊髓内炎性细胞浸润的程度,其神经保护作用可能是通过上调Nrf2及HO-1的表达,发挥抗氧化应激作用来实现的。

Objective：To study the effect of edaravone on EAE rats and the underlying mechanism.Methods：Wistar rats were immunized with GPSCH,and randomly divided into control group,EAE group,dexamethasone group,low dose of edaravone group and high dose of edaravone group.The morbidity of disease and clinical signs were observed.The pathological changes of spinal cord tissue sections were observed under light microscopy after HE staining and trichrome staining.The expression of Nrf2 and HO-1 was observed by immunohistochemistry.Results：Morbidity of high dose of edaravone group （8.33%） and DXM group （0%） was significantly lower than in EAE group （58.3%） （P0.05）;At the 16th day neurological deficit scores of high dose of edaravone group （0.32±1.10） and DXM group （0） were significantly lower than those of EAE group （2.06±2.01） and low dose of edaravone group （1.21±1.51） （P0.05）;The extent of inflammation of high dose of edaravone group （1.25±1.67） and DXM group （0） were significantly lower than those of EAE group （8.17±3.49） and low dose of edaravone group （7.67±4.37） （P0.05）;The degree of demyelination in the white matter and injury of axon of in high dose of edaravone group were lower than in EAE group and low dose of edaravone group;The expression of Nrf2 and HO-1 in spinal cord was all upregulated compared with that of control group,and those in the high dose of edaravone group was the highest.Conclusion：Edaravone reduces the morbidity of EAE rats,alleviates the severity of the disease and reduces the lymphocyte infiltration and inflammation in the spinal cord of EAE rats.Edaravone＇s neuroprotective effect may be through upregulation of Nrf2 and HO-1.