Central Nervous System/drug effects; Encephalomyelitis, Autoimmune, Experimental/drug therapy; Ribavirin/analogs & derivatives; Ribavirin/pharmacology; Animals; Antimetabolites, Antineoplastic/pharmacology; Antiviral Agents/pharmacology; Central Nervous System/pathology; Central Nervous System/physiopathology; Chemotaxis, Leukocyte/drug effects; Chemotaxis, Leukocyte/immunology; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Synergism; Drug Therapy, Combination; Encephalomyelitis, Autoimmune, Experimental/pathology; Encephalomyelitis, Autoimmune, Experimental/physiopathology; Gliosis/drug therapy; Gliosis/immunology; Gliosis/physiopathology; Immunosuppression Therapy/methods; Male; Multiple Sclerosis/drug therapy; Multiple Sclerosis/pathology; Multiple Sclerosis/physiopathology; Myelin Sheath/drug effects; Myelin Sheath/immunology; Myelin Sheath/pathology; Rats; Treatment Outcome; Wallerian Degeneration/drug therapy; Wallerian Degeneration/immunology; Wallerian Degeneration/physiopathology