The aim of this study was to evaluate the therapeutic effect of YGPs in MOG35–55-induced EAE mice and to further elucidate the underlying molecular mechanism. Methods: Female C57BL/6 mice were divided into six groups, including the non-treated EAE model, prednisone acetate- and 1.2, 2.4 or 4.8 g/kg YGPs-treated EAE groups, and a normal control group. The EAE model was established by injecting the mice subcutaneously with MOG35–55 antigen. The body weights were measured and the neurological functions were scored in each group. The pathology and morphology of the brain and spinal cord was examined. The expression of MAP-2 was detected by immunofluorescent staining. The levels of netrin1, DCC, RhoA, Rac1, and Cdc42 were assayed by immunohistochemistry, qRT-PCR and Western blot on day 40 post-immunization (PI).
YGPs treatments significantly reduced neurological function scores in EAE mice, where the inflammatory infiltration was reduced and the axon and myelin damage in both brain and spinal cord was alleviated. In the brain and spinal cord tissues, YGPs increased the expression of neuronal factors MAP-2, netrin1 and DCC. The expression of Rac1 and Cdc42 were increased, while RhoA was reduced following YGPs treatments.
Our results demonstrated that YGPs exhibited a neuroprotective effect on promoting nerve regeneration at the brain and spinal cord in EAE mice induced by MOG35–55. Netrin1, DCC and the Rho family GTPases of RhoA, Racl, Cdc42 were involved in mediating the effects of YGPs on nerve regeneration.