title: Sleep deprivation attenuates endotoxin-induced cytokine gene expression independent of day length and circulating cortisol in male Siberian hamsters (Phodopus sungorus).
abstract: Sleep is restorative, whereas reduced sleep leads to negative health outcomes, such as increased susceptibility to disease. Sleep deprivation tends to attenuate inflammatory responses triggered by infection or exposure to endotoxin, such as bacterial lipopolysaccharide (LPS). Previous studies have demonstrated that Siberian hamsters (Phodopus sungorus), photoperiodic rodents, attenuate LPS-induced fever, sickness behavior and upstream pro-inflammatory gene expression when adapted to short day lengths. Here, we tested whether manipulation of photoperiod alters the suppressive effects of sleep deprivation upon cytokine gene expression after LPS challenge. Male Siberian hamsters were adapted to long (16 h:8 h light:dark) or short (8 h:16 h light:dark) photoperiods for >10 weeks, and were deprived of sleep for 24 h using the multiple platform method or remained in their home cage. Hamsters received an intraperitoneal injection of LPS or saline (control) 18 h after starting the protocol, and were killed 6 h later. LPS increased liver and hypothalamic interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF) gene expression compared with vehicle. Among LPS-challenged hamsters, sleep deprivation reduced IL-1 mRNA levels in liver and hypothalamus, but not TNF. IL-1 attenuation was independent of circulating baseline cortisol, which did not increase after sleep deprivation. Conversely, photoperiod altered baseline cortisol, but not pro-inflammatory gene expression in sleep-deprived hamsters. These results suggest that neither photoperiod nor glucocorticoids influence the suppressive effect of sleep deprivation upon LPS-induced inflammation.
authors.affiliation: Department of Neuroscience and Institute of Behavioral Medicine Research, Wexner Medical Center, The Ohio State University, Columbus, OH 43210 USA. noah.ashley@wku.edu
authors.forename: Noah T
authors.initials: NT
authors.lastname: Ashley
authors.forename: James C
authors.initials: JC
authors.lastname: Walton
authors.forename: Achikam
authors.initials: A
authors.lastname: Haim
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Laura A
authors.initials: LA
authors.lastname: Prince
authors.forename: Allison M
authors.initials: AM
authors.lastname: Fruchey
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Lieberman
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Weil
authors.forename: Ulysses J
authors.initials: UJ
authors.lastname: Magalang
authors.forename: Randy J
authors.initials: RJ
authors.lastname: Nelson
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D006224:Cricetinae; D016207:Cytokines / Q000276:immunology*; D017931:DNA Primers / Q000235:genetics; D004731:Endotoxins / Q000633:toxicity*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D006854:Hydrocortisone / Q000097:blood*; D007031:Hypothalamus / Q000378:metabolism; D007375:Interleukin-1 / Q000378:metabolism; D008070:Lipopolysaccharides; D008099:Liver / Q000378:metabolism; D008297:Male; D017111:Phodopus / Q000378:metabolism / Q000502:physiology*; D017440:Photoperiod; D011863:Radioimmunoassay; D060888:Real-Time Polymerase Chain Reaction; D012892:Sleep Deprivation / Q000378:metabolism / Q000503:physiopathology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; D017931:DNA Primers; D004731:Endotoxins; D007375:Interleukin-1; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D006854:Hydrocortisone
keywords: Siberian hamster; cortisol; cytokine; endotoxin; hypothalamus; inflammation; interleukin-1; photoperiod; sleep deprivation