Protective Effect of Rolipram in Experimental Autoimmune Neuritis: Protection is Associated with Down-Regulation of IFN-γ and Inflammatory Chemokines as Well as Up-Regulation of IL-4 in Peripheral Nervous System

Rolipram, a phosphodiesterase type 4 inhibitor, is reported to have anti-inflammatory effects. It can markedly downregulate antigen-driven T cell proliferation and suppress TNF-ot and TNF-(3 production in vitro and in vivo, which have led to its use in the treatment of a number of autoimmune disorders including experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune neuritis (EAN). EAN is a CD4+ T cell-mediated demyelinating autoimmune disease of peripheral nervous system (PNS) that represents an animal model for the study of the immunopathogenesis and immunotherapy of Guillain-Barre syndrome (GBS) in human. In the previous study, we reported that suppression of EAN by Rolipram was associated with down-regulated myelin antigen-induced T cell responses as well as downregu-lated IFN-γ and TNF-α production. Here we report that EAN induced in Lewis rats by inoculation with the PNS P2 protein peptide 57-81 and Freund's complete adjuvant (FCA), was strongly suppressed by Rolipram administered twice daily intraperitoneally from day 9 post immunization (p.i.), i.e. after onset of clinical EAN to day 18 p.i. This clinical effect was associated with dose-dependent down-regulated production of IFN-γ and the chemokines macrophage inflammatory protein-la (MlP-la), MIP-2 and monocyte chemotactic protein-1 (MCP-1) as well as up-regulated IL-4 production in sciatic nerve sections from Rol-ipram-treated EAN rats at maximum of clinical EAN, i.e. on day 14 p.i. These findings suggest that Rolipram may be useful in certain T cell-dependent autoimmune diseases and inflammatory neuropathies. These observations call for further studies on the potential role of Rolipram in the treatment of autoimmune diseases