Preventive and therapeutic effects of the selective Rho-kinase inhibitor fasudil on experimental autoimmune neuritis

We studied the effects of fasudil, a selective Rho-kinase inhibitor, on experimental autoimmune neuritis (EAN). Continuous parenteral administration of fasudil prevented the development of EAN induced by P0 peptide 180–199 in Lewis rats while it also reduced EAN severity when administered after disease onset. Immunohistochemical examination disclosed a marked decrease in the amount of inflammatory cell infiltration and attenuation of demyelination and axonal degeneration. Specific proliferation of lymphocytes from fasudil-treated rats in response to P0 peptide was significantly reduced as compared with those from phosphate-buffered saline (PBS)-treated rats. Fasudil treatment was associated with a significant reduction in secretion of IFN-γ; by contrast, secretion of IL-4 was almost the same in the fasudil- and PBS-treated groups. As a result, the IFN-γ/IL-4 ratio in the supernatant was significantly deceased in fasudil-treated rats compared with PBS-treated ones. Therefore, our results indicate a beneficial effect of selective blockade of Rho-kinase in animals with autoimmune inflammation of the peripheral nerves, and may provide a rationale for the selective blockade of Rho-kinase as a new therapy for Guillain-Barré syndrome.