| Objective:Multiple sclerosis(MS) is a common demyelination disease of the centralnervous system(CNS). The main pathological features is that demyelination,glial cell proliferation, axonal lesions and progressive neurologicaldysfunction. But the exact etiology and pathogenesis is not clear. Now it isbelieved that environmental factors, genetic susceptibility, autoimmune andother factors were related.At present, some studies at home and abroad have shown that: oxidativestress play a very important role in the pathogenesis of MS. Oxygen freeradicals and other metabolites generated by Oxidative stress can oxidizebiological macromolecules in vivo, induce free radical chain reaction, generatea large number of lipid peroxidation, cause membrane damage, a variety ofsubcellular structural damage, enzyme activity decreased or disappeared,cause cell autolysis.The related foreign studies: the damage of mitochondrial structure andfunction is mediated by inactivation of mitochondrial protein and oxidativestress, mitochondrial dysfunction leading to programmed cell death,eventually leading to animal axonal and neuronal degeneration inexperimental autoimmune encephalomyelitis, which is the model of multiplesclerosis. At the same time that the morphology and function of mitochondriadamage occurs early in the course of the disease began, mitochondrial damageextent and severity of illness closely related. Mitochondrial damage moreserious, the worse the prognosis of MS.α-lipoic acid as a strong antioxidant, has attracted wide attention of people.It belongs to vitamin B compounds, is a natural anti-oxidants. It is mainly through scavenging free radicals, chelating metal ions, recycled from otheranti-oxidants play its antioxidant activity. At abroad, it through interventionthe process of oxidative stress, reducing free radical damage of blood vesselsand nerves has been used to treat diabetic peripheral neuropathy and hasachieved good efficacy. There is little research on α-lipoic acid and multiplesclerosis at home and abroad, However, α-lipoic acid on Mitochondrialdamage in MS whether the protective effect is unclear.In this study, by establishing a model of multiple sclerosis-experimentalautoimmune encephalomyelitis (EAE), related indicators of mitochondriadamage were detected in the pathogenesis of rats, to understand mitochondriadamage in the pathogenesis of MS. By α-lipoic acid on the intervention ofEAE in rats to observe the corresponding changes in indicators ofmitochondria damage, understanding of protective effect for mitochondriadamage, and thus for clinical treatment of MS to provide new ideas andexperimental evidence.Methods:A total of70adult healthy female Wistar rats with body weighing between180and200g were divided randomly into different groups: normal controlgroup(NC,8rats), with complete Freund's adjuvant plus saline injection ofanimal, other rats were immunized by fresh guinea pig spinal cordhomogenate(GPSCH). After they first paroxysm, divided randomly out6ratsas disease group(DIS),others divided randomly into EAE group,dexamethasone(DXM2mg/kg.d) group, alpha-lipoic acid (LA100mg/kg.d)group, and the3groups were divided into Remission group(REM), relapsegroup(REL) two sub-groups according to the course of the disease. Norecurrence in DXM group and; LA group, according to the separately meandays of remission and relapse of EAE in preliminary experiments, the ratswere divided into7days group after intervention (DXM7d group; LA7dgroup)and14days group after intervention (DXM14d group; LA14d group).The weight of rats and its clinical score were made daily. The brain tissue wasstained with HE and observed by which inflammatory cells infiltration, The observation of ultrastructure in the electron microscope. The brain was madeof the homogenate samples, the extraction of mitochondria, the application ofCoomassie brilliant blue to determine protein content, chemical colorimetricto determine the content of Na+/K+ATPase.Results:1. The clinical appearance and the relapse of disease in different group:Most of the EAE rats emerge the clinical appearance at the11th day afterimmunization, and reach the peak of the disease at the14th day afterimmunization, and then decline. There is no incidence of rats in the controlgroup. Comparison of the relapse of disease in three groups, we found thefrequency of EAE attacks in EAE group were higher that the treatment groups(P <0.05). No statistical significance between the LA group and DXM group(P>0.05).2. Clinical profile of EAE in different groupNeurological deficits scores of DXM group,LA group were lower thanthose of EAE group (P <0.01). No statistical significance between the LAgroup and DXM group (P>0.05).3．Histopathology:3.1.HE staining:Central nervous tissue of rats in each group are visible to varying degrees ofinflammatory cell infiltration, particularly the degree of infiltration ofinflammatory cells is most significant in the brain of onset group, aroundblood vessels showed dense infiltration of inflammatory cells in the cuffsample. The infiltration of inflammatory cells in the rat central nervous tissueof the intervention group have a lesser extent.3.2Electron microscopeThe main pathological change was myelin lamellar loose with myelindamage, demyelination, axonal swelling, osteoporosis, swelling ofmitochondria, vacuolization, cristae dissolution at the crest-time of the disease;There was mitigation of damage to myelin co-exist with relatively completemyelin axons within the structure is vague, mitochondria can also be found vacuolization, sparse crest at paracmasis of the disease; There was severeaxonal lesions, vacuolization of axons disappear even more severemitochondrial vacuolization at relapse of the disease. The intervention groupsalso can see the change, but its extent is relatively light.4. the determination of Na+/K+ATPaseIn normal group, the content of Na+/K+ATPase was most; the content ofNa+/K+ATPase decreased in the disease period, an increase in the remissionperiod, the content decreased again in the relapse period; by DXM, and LAintervention,the content of Na+/K+ATPase increased.Conclusions:1The content of Na+/K+ATPase in brain tissue are associated with theactivity of EAE, with the course of development has been a definite trend.There is a certain influence of drug intervention on various indicators.2LA reduces the morbidity, and protects the rats from the severity of thedisease.3α-lipoic acid on EAE in rats have protective effect on axonal injury andits protective effect may be adopted to achieve by anti-oxidative stress. |
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