Fasudil Inhibits The Infiltration Of Inflammatory Cells By Upregulating Occludin Expression In Experimental Autoimmune Encephalomyelitis

Objective:In this study, we explored the therapeutic effect of Fasudil at different stages of experimental autoimmune encephalomyelitis, and studied possible mechanisms of the action, providing experimental basis for further clinical treatment of multiple sclerosis (MS).Methods:Chronic EAE model was established in female C57BL/6mice immunized with MOG35-55. After immunization,42mice were randomly divided into EAE group, Fasudil early treatment group and the Fasudil late treatment group. Fasudil in early treatment group was intraperitoneal injected (40mg/kg/d, once/d), at day3after immunization, consecutive to day30after immunization. Fasudil in late treatment group was injected at onset of EAE in similar manner. Normal saline was injected as EAE control group. Clinical score was evaluated and body weight was reported every other day. The animals were sacrificed at day30after immunization. Spinal cords and brains were collected for HE staining and immunofluorescence staining. The extraction from spinal cord was used to detect the expression of Occludin protein. Data were analyzed using the Graphpad the Prism software.Results:1. As compared with EAE control, Fasudil treatment reduced EAE incidence rate, delayed EAE onset, and reduce the symptoms of EAE. Fasudil early treatment group and late treatment group compared with group EAE, the change of body weight and onset time were all prolonged (P<0.01,P<0.05). Fasudil early treatment was better than late treatment.2. Fasudil inhibited the infiltration of inflammatory cells in the central nervous system. HE staining showed inflammatory cell infiltration in brain stem, cerebellum, brain and spinal cord white matter, mainly lymphocytes and monocytes. Fasudil treatment significantly inhibited the invasion of inflammatory cells.3. Fasudil downregulated the expression of p-MYPT1in CNS CD31-positive endothelial cells, compared with EAE group, the expression of p-MYPT1on CD31positive endothelial cells were decreased (P<0.01,P<0.05, reopectively) in Fasudil early treatment group and late treatment group, suggesting that Fasudil inhibited ROCK activity in brain endothelial cells.4. Fasudil induced the expression of endothelial cell tight junction protein Occludin in the CNS, thereby improving the integrity of the BBB permeability, and reducing the invasion of inflammatory cells. The activation of Occludin protein in spinal cords were all increased (P<0.05) in Fasudil early treatment group and late treatment group.Conclusion:Our results show therapeutic potential of Fasudil in EAE, early treatment is better than late treatment. Fasudil inhibited the infiltration of inflammatory cells, reduced the expression of p-MYPT1in the brain endothelial cells, and induced the expression of Occludin protein. Fasudil inhibited ROCK activity in cerebral vascular endothelial cells, induced the expression of Occludin, thus inhibiting the central infiltration of inflammatory cells, and ultimately preventing the occurrence and development of the disease.