Novel environment influences the effect of paradoxical sleep deprivation upon brain and peripheral cytokine gene expression

Sleep loss increases inflammatory mediators in brain and peripheral tissues, but the mechanisms underlying this association are not fully understood. Male C57BL/6j mice were exposed to paradoxical sleep deprivation (PSD) for 24 h using the modified multiple platform (MMP) technique (platforms over water) or two different controls: home cage or a dry platform cage, which constituted a novel environment. PSD mice exhibited increased IL-1 beta and TNF-alpha pro-inflammatory gene expression in brain (hypothalamus, hippocampus, pre-frontal cortex), as well as in peripheral tissues (liver, spleen), when compared with home-cage controls. In addition, among PSD mice, TGF beta 1, an anti-inflammatory cytokine, was increased in pre-frontal cortex, liver, and spleen in conjunction with elevated serum corticosterone concentration relative to home-cage controls. However, these differences were nearly abolished when PSD mice were compared with control mice subjected to a dry MMP cage, suggesting that simply exposing mice to a novel environment can induce an acute inflammatory response. (C) 2016 Elsevier Ireland Ltd. All rights reserved.