Establishment of a Myelin Basic Protein Fragment-Induced Wistar Rat Model of Autoimmune Encephalomyelitis / 中国实验动物学报

ABSTRACT

Objective To establish an experimental autoimmune encephalomyelitis (EAE) model in Wistar rats with myelin basic protein fragment (MBP69-85) and observe its pathological changes. Methods MBP69-85 dissolved in normal saline was mixed with complete Freund's adjuvant (CFA) (including 6 mg bacille Calmette Guerin) to prepare the encephalitogenic emulsion. Ten out of 70 Wistar rats were chosen as a control group, the others were divided equally into group A,B,C according to the difference of the encephalitogenic emulsion. Rats in group A were immunized with 50 μg MBP69-85 +CFA (including 6 mg BCG). Rats in group B were immunized with 25 μg MBP69-85+CFA (including 6 mg BCG). Rats in group C were immunized with 25 μg MBP69-85+CFA (including 12 mg BCG). The pathological changes of brain and spinal cord tissues were examined by light microscopy after HE staining and immunohistochemistry of MBP and NF. Results Some of the Wistar rats immunized with 50 μg MBP69-85 showed disorder at 12～16 days after immunization. The clinical symptoms included tail acratia or paralysis of tail and limbs, head tilt, etc. and the mean score was 2.38±1.89. There were infiltration of inflammatory cells inside nervous tissue and perivascular cuffings in HE stained sections. The immunohistochemistry of MBP and NF showed demyelination in the white matter and axon injury. Conclusion To some extent, the establishment of EAE depends on the dose of the immunizing antigen. The BCG in CFA was not the major cause of morbility of the rats. The EAE model induced with MBP69-85 in Wistar rats, showing typical clinical symptoms and pathological changes of multiple sclerosis, is a reliable animal model for the study of pathogenesis and treatment of multiple sclerosis.