Cytokines reduce toxic effects of ethanol on oligodendroglia

To characterize immunomodulatory mechanisms that affect oligodendroglia (OL) and white matter following ethanol exposure during early CNS development, we investigated the direct effects of ethanol and cytokines on glia. Mixed glial cultures from newborn rat brain were exposed to 6.5-130 mM ethanol for 1-3 days. OL were sensitive to ethanol, with death ranging from 32 to 88% with increasing time and ethanol concentrations. Little cell death occurred in astroglia or microglia. Mixtures of cytokines representative of those produced by pro-inflammatory Th1 and monocyte/macrophage (M/M) cells as well as those produced by anti-inflammatory Th2 cells were all protective. Three of the cytokines in the Th1 mixture, IL-2, TNF-α and IFN-γ, were protective individually, although no single cytokine was as effective as the mixture. The protective effects of the Th1 mixture and of IL-2 were reversed by inhibition of both MAP kinase and PI-3 kinase signaling pathways. We conclude that cytokines can act either directly on OL or indirectly through effects on astroglia or microglia to protect OL from ethanol toxicity.