The Influence Of The Treatment And The Expresstion Of Nrf2 In EAE Mice Which Were Treated By Alpha Lipoic Acid

Objective:Multiple sclerosis(MS)is an common autoimmune demyelinating disease that results in disabilty of young adults primarily, the pathological mechanisms is unclear, many risk factors such as genetic and environmental factors promote the course of MS, recently years, more and more people pay attention to one of the pathological mechanisms- oxidative stress.The nuclear factor erythroid 2 related factor 2(Nrf2), a member of cap ‘n' collar family, belongs nuclear transcription factor. It binds to the antioxidant response element(ARE) in several disorders including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis so on, to enhance the ability of antioxidant stress and cellular protection, reduce the damage of the nerve and delay the progress of the disease. Therefore, Nrf2 as the key regulator of the anti-oxidative stress becomes the focus of the study and the new direction of the treatment.Alpha lipoic acid(?-LA) is an natural antioxidant, the experiment relied on experimental autoimmune encephalomyelitis(EAE)mice which were treated by alpha lipoic acid and tried to observe the clinical features,for example, neurological deficit score, weight, mental condition and activities so on, and the expresstion of Nrf2 in lumbar enlargement of spinal cord. We studied the role of alpha lipoic acid in treating and protecting the EAE mice and the expression of Nrf2, meanwhile we also investigated the mechanism about antioxidant stress of alpha lipoic acid in EAE mice, it could provide a new theoretical and experimental basis for the clinical treatment of MS.Methods:At first, to establish EAE model which was induced by peptide fragment of myelin oligodendrocyte glycoprotein(MOG), the neurological deficit score of EAE mice?0.5 points as the standard of successful model.The second, experimental animals and groups. 36 C57BL/6 mice after onset were randomly grouped in two groups including EAE group and alpha lipoic acid group, every group had 18 mice respectively; meanwhile, 18 normal mice was chosen randomly as normal control group.The third, the methods of intervention. Isopyknic dimethyl sulphoxide(DMSO)were injected in enterocoelias which belong to the mice of normal control group and EAE group everyday during fourteen days;meanwhile, alpha lipoic acid group were injected alpha lipoic acid with 15mg/kg/d.The fourth, the targets of observation. To observe the clinical features, such as neurologic deficit score,weight, mental condition and activities so on 0 day, 7day, 14 day after illness respectively; then executed the mice to take up the lumbar enlargement of spinal cord, we observed the results of histopathology in lumbar enlargement of spinal cord which included the invasive degree of inflammatory cells and the expression of Nrf2, in addition, we also measured the expression of Nrf2 mRNA by real-time PCR in lumbar enlargement of spinal cord of the experimental mice.Results:1 The general situations and clinical features of the experimental mice in three groups: the clinical features of normal control group mice showed normal mind and appetite, glossy fur, flexible activities and increased weight; after immmuned tenth day,the mice in alpha lipoic acid group and EAE group began to become weak, the main features included decreasing weight and appetite, deteriorative mentality and activities, and dim furs so on, the clinical features were less serious in alpha lipoic acid group than EAE group. 2 Compared the weight seventh day after illness among normal control group, EAE group and alpha lipoic acid group: the weight was decreased in EAE group and alpha lipoic acid group compared with normal control group(P<0.05), mice in EAE group was more obvious than alpha lipoic acid group(P<0.05). 3 To record the neurological deficit score seventh day after illness of normal control group, EAE group and alpha lipoic acid group : compared to normal control group, the neurological deficit score more higher in EAE group and alpha lipoic acid group(P<0.05),while, the EAE group mice were the most serious(P<0.05). 4 HE staining: the lumbar enlargement of spinal cord of mice in EAE0, EAE7, EAE14 group showed the infiltration of inflammatory cells, all of these groups, the infiltration of inflammatory cells in EAE7 group was the most serious; all alpha lipoic acid groups had a similar features, but more lighter and the number of inflammatory lesions was more less. 5 Immunohistochemical staining: compared to normal control group, the number of positive cells were lower in lumbar enlargement of spinal cord of mice in EAE0, EAE7, EAE14(P<0.05); the number of positive cells in alpha lipoic acid 7 group and alpha lipoic acid 14 group were more higher than normal control group(P<0.05); alpha lipoic acid 7group were higher than EAE7group(P<0.05); similarly, alpha lipoic acid 14 group were higher than EAE14 group(P<0.05). 6 Real-time PCR: compared to normal control group, the expression of Nrf2 mRNA were lower in EAE14 group(P<0.05); alpha lipoic acid 7 group were higher than EAE7group(P<0.05); alpha lipoic acid 14 group and EAE14, the expression were similar, the difference was not statistically significant(P>0.05).Conclusions:1 The decline of the weight was indicative for the onset of the disease; neurological deficit score also was significant for us to evaluate the severity of the illness. Alpha lipoic acid can protect the EAE mice to improve the clinical features containing mental condition, appetite and activeties, delay the downregulation of the weight and improve neurological deficit score.2 Nrf2 is a key factor of antioxidant stress, alpha lipoic acid can up-regulation the expression of Nrf2 in EAE mice, it's may be the pathways of enhance the antioxidant stress in EAE mice.