SEQUENTIAL EXPRESSION OF MESSENGER-RNA FOR PROINFLAMMATORY CYTOKINES AND INTERLEUKIN-10 IN THE RAT PERIPHERAL NERVOUS-SYSTEM - COMPARISON BETWEEN IMMUNE-MEDIATED DEMYELINATION AND WALLERIAN DEGENERATION

This study examined the time course of mRNA levels of the proinflammat ory cytokines interferon-gamma (INF gamma), interleukin-1 beta (IL1 be ta), interleukin-12 (IL12; p40 subunit), and the immunosuppressant int erleukin-10 (IL10) by semiquantitative reverse transcription polymeras e chain reaction (RT-PCR) in rats with actively induced experimental a utoimmune neuritis (EAN) and in distal stumps of crushed sciatic nerve s undergoing Wallerian degeneration, In EAN IFN gamma- and IL1 beta-mR NA peaked at the onset and acute phase of clinical disease, IL12p40-mR NA was upregulated later than IFN gamma-mRNA in the late acute phase f rom days 15 to 21, IL10-mRNA appeared concomitantly with the proinflam matory cytokines at day 11, but persisted at high levels into the clin ical recovery phase, After nerve crush both IL1 beta- and IL10-mRNA we re rapidly upregulated in the distal stump at day 1 and slowly decline d over the next 2 weeks, Significant levels of mRNA for IFN gamma coul d be found at days 4 and 7, whereas IL12p40-mRNA showed a biphasic ind uction, We provide evidence for a concomitant induction of pro-and ant i-inflammatory cytokines in EAN, Moreover, the rapid upregulation in W allerian degeneration suggests a more general role of cytokines in the biology of the peripheral nerve. (C) 1998 Wiley-Liss, Inc.