Chronic Ethanol Feeding Modulates Inflammatory Mediator Activation of Nuclear Factor-kB, and Eesponsiveness to Endotoxin in Murine Kupffer Cells and Circulating Leukocytes

摘要

Chronic ethanol abuse is known to increase susceptibility to infections after injury, in part, by modification of macrophage function. Several intracellular signalling mechanisms are involved in the initiation of inflammatory responses, including the nuclear factor-tcB (NF-kB) pathway. In this study, we investigated the systemic and hepatic effect of chronic ethanol feeding on in vivo activation of NF~kB in NF-/cBEGFP reporter gene mice. Specifically, the study focused on Kupffer cell proinflammatory cytokines IL-6 and TNF-a and activation of NF-zcB after chronic ethanol feeding followed by in vitro stimulation with lipopolysaccharide (LPS). We found that chronic ethanol upregulated NF-kB activation and increased hepatic and systemic proinflammatory cytokine levels. Similarly, LPS-stimulated IL-ljS release from whole blood was significantly enhanced in ethanol-fed mice. However, LPS significantly increased IL-6 and TNF-a levels. These results demonstrate that chronic ethanol feeding can improve the responsiveness of macrophage LPS-stimulated IL-6 and TNF-a production and indicate that this effect may result from ethanol-induced alterations in intracellular signalling through NF-kB. Furthermore, LPS and TNF-a stimulated the gene expression of different inflammatory mediators, in part, in a NF-/cB-dependent manner.