DIFFERENTIAL EXPRESSION OF INTERLEUKIN-10 MESSENGER-RNA IN WALLERIAN DEGENERATION AND IMMUNE-MEDIATED INFLAMMATION OF THE RAT PERIPHERAL NERVOUS-SYSTEM

Interleukin-10 (IL-10) is a potent immunosuppressant cytokine which do wnregulates MHC class II antigen expression and inflammatory cytokine production, In this study we localized mRNA for IL-10 in the rat perip heral nervous system (PNS) by nonradioactive in situ hybridization usi ng a digoxygenin-labeled riboprobe specific for rat IL-10. IL-10 mRNA was expressed by some Schwann cells (SCs) in the normal Sciatic nerve, During Wallerian degeneration, SCs strongly expressed IL-10 mRNA betw een days 2 and 4 after transection, By day 14 only occasional cells we re positive for IL-10 mRNA, The vast majority of ED1-positive macropha ges were IL-10 negative after axotomy, Contrastingly, infiltrating mac rophages expressed IL-10 mRNA conincident with beginning clinical reco very in experimental autoimmune neuritis (EAN), the rat model of human Guillain-Barre syndrome, Our data suggest that SCs provide a constitu tive immunosuppressant system in the PNS, In EAN additional macrophage -derived IL-10 may be important for the resolution of the T cell-media ted immune response. (C) 1996 Wiley-Liss, Inc.