The Dynamic Observation Of Demyelination In A Long Term EAE Rats' Model Induced By Low Dose GPSCH And The Protective Effects Of Alpha-lipoic Acid

Objective: Multiple sclerosis(MS) is one kind of central nervous system(CNS) demyelinating diseases, which typical course is relapse-release and aggravation in progress. The pathogenesy is not clear and there is no active treatment. After demyelination of CNS, the spontaneous remyelination is not sufficient. So there are no myelin to protect naked axon. Finaly, the axon are damaged secondary. Above all, it is effective treatment to protect the myelin and promote the remyelination in MS. As an antioxidant and immunity regulator,α-lipoic acid may alleviate oxidation and immune damage, and can protect and promote the remyelination in MS. Myelin basic protein(MBP) is a main composition of myelin which is important for maintaining the membrane layer of myelin sheath. MBP liberates from myelin sheath when myelin has been destoried. The impairment of myelin sheath in CNS can be indirect conclude by detect the MBP protein in cerebrospinal fluid, but its content is little and hard to obtain. so we take direct measure the MBP protion in CNS.Methods: The experimental autoimmune encephalomyelitis(EAE) is a ideal animal modle. In our experiments, EAE was induced by immunization of female Wistar rats with Low-dose guinea pig spinal cord homogenate(GPSCH) and carry on a long-term observation(180d). In this study, the EAE rats were treated withα-lipoic acid.The therapeutic efficacy was judgement by nerve function score, staining of myelin, electron microscope and Western Blot, et al.Meanwhile, using ELISA to test TNF-βand TGF-α, flow cytometric art technology to test Treg cells level.Results:1 There are significant difference in the nerve function score and recurrence rate between Lipoic acid intervention group and Natural course group,P <0.01(fig.2 and table.1). There are no obvious difference in latency between the two groups, because rats were injected with LA at onset. No incidence in Adjuvants group.2 There are inflammatory cells in Natural course group and Lipoic acid intervention group on 7d after onset (fig.4).3 The myelin sheath loose in Lipoic acid intervention group and Natural course group by electron microscope and Trichrome stain(fig 5 and 7). There are myelin fragments in natural course group on 180d after onset(fig.8A). Myelin sheath damage is light in LA group on 180d after onset(fig.8B). The myelin sheath is normal in the Adjuvants group (fig. 6).4 MBP expression by Western Blot show that there are no differences between the three groups on 7d after onset; Comparing to the Adjuvants group there are differences in the Lipoic acid intervention group (P<0.05)and Natural course group(P<0.01)on 180d after onset. Comparing to natural course group, there are differences in the Lipoic acid intervention group on 180d after onset. (P<0.05 ,chart.2,fig.9,fig.10). Indicating that LA has protecting effects of myelin sheath.5 ELISA test results showed that on 7d after onset and on 14d after onset the levels of TNF-αin serum are increased in both Natural course group and Lipoic acid intervention group.and the trends of TGF-βand CD4~+CD25~+Foxp3~+T cell are oppsite to TNF-α(chart.3). There are no difference between the three groups on 180d after onset( fig.3,4,5, chart.11,12,13).Conclusion:Through 180d's observation we found that LA can inhibit inflammation, reduce the recurrence,protect myelin sheath, promote myelin regeneration. Therefore , the LA can serve as an effective drugs in MS.