Objective To study the pathological changes of relapsing-remitting experimental allergic encephalomyelitis(EAE) in Wistar rat.Method\ Tissue sections were processed with HE staining,Weil myelin staining and modified Bielschowsky staining.The expression and distribution of MMP-2 and-9 were detected with the method of IHC.Result There were many perivascular cuffings in tissues accompanied by large pieces of demyelination and inflammatory cells infiltrating into partial demyelinated tissues,axons with some vesicular loss,strong postive GFAP around the old lesion,and MMP-2 and-9 were expressed in vascular endothelial cells,meninges,ECM and inflammatory cells.Conclusion(1) Pathological changes of relapsing-remitting EAE in rat were in coincidence with the clinical manifestations of patients and there were active and inactive lesions in the tissues.(2) MMP-2 and-9 were expressed in the active lesions and they participated in the pathogenesis.(3) Pathological changes of relapsing-remitting EAE were similar to multiple sclerosis and such rats are an ideal animal model.