Establishment Of Animal Model For Experimental Allergic Encephalomyelitis In BALB/c Mice And Preliminary Study On The Pathogenic Mechanism Of EAE

Objective:This study was carried out to construct the mouse model of the experimental allergic encephalomyelitis (EAE) for better understanding of its pathogenesis.Method:The emulsionized antigen adjuvant was obtained by mixation of myelin basic protein (MBP) and Freund's complete adjuvant, and then immunized the BALB/c mouse at the 0 day and 7 day. For the high dose group, each mouse was immunized 0.2ml antigen adjuvant emulsification containing 400μg MBP and 0.1ml Pertussis vaccine, the low-dose group injected 0.2ml antigen adjuvant emulsification containing 200μg MBP and 0.1ml Pertussis vaccine, 0.3ml of PBS with complete freund's adjuvant (CFA) and Pertussis vaccine as a control. The clinical manifestation of each group was analyzed and marked. The brain tissue of experiment group, control group or normal group had apparente clinical manifestation after secondary immunization which were sliced and HE stained, and the pathological change was analyzed for the different dosage of antigen in the incidence of the experimental allergic encephalomyelitis. The splenic lymphocytes were isolated in sterile condition, and stimulated by phytohemagglutinin (PHA), the IFN-γin the supernatant was detected by ELISA. The autoantibody level was also inspected by ELISA. Single cell suspension was obtained from the mouse spleen and the number of CD4+ T and CD4+CD25+ T cells was counted by flow cytometry after 10μl monoclonal antibody was added into the cells.Results:Most of the mice in experiment group were appeared clinical manifestation, such as action sluggish and tail acratia, were appeared at the 3 day after antigen injected. After the secondary immunization, the experiment mice were gradually descreased foodintake, moving slowly, back-bow, midrange acratia of posterior or anterior limb, claudication, even completely paralyzed or dead, etc. In the high-dose group, 9 mice were appeared tail acratia (Grade 1), 3 mice were midrange acratia of posterior or anterior limb (Grade 2), 1 mouse posterior limb acratia severely and claudication (Grade 3), 3 mice dead (Grade 5), the morbidity was 89%. In the low-dose group, 8 mice were tail acratia, 2 mice were midrange acratia of posterior or anterior limb, and 1 mouse dead, the morbidity was 61%.There was not above clinical manifestation in the control group.!nflammatory cells infiltrate around the blood vessel of the brain tissue of experiment group mice were observed by light microscope, the other pathological change were oversleeve-like change and brain tissue looseness. There was no such change in control group.The IFN-γlevel was increased, compared with the control group, and the number of CD4+ T was also increased, the ratio of CD4+ CD25+ T/ CD4+ T was decreased.Conclusion:(1)The the mouse model of the experimental allergic encephalomyelitis was constructed and the model was stable, and reliable.(2)The level of IFN-γwere increased in experimental animals in this study. This may be the reason why autoreactivity type 1 helper T lymphocyte cells proliferation. CD4+ T cells pay key roles in the pathogenisis of the experimental allergic encephalomyelitis,and the ratio change of CD4+ CD25+ Treg / CD4+ T cells could be one of pathogenic mechanism of EAE.