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Author (up) Bedrosian, T.A.; Fonken, L.K.; Walton, J.C.; Nelson, R.J. url  doi
openurl 
  Title Chronic exposure to dim light at night suppresses immune responses in Siberian hamsters Type Journal Article
  Year 2011 Publication Biology Letters Abbreviated Journal Biol Lett  
  Volume 7 Issue 3 Pages 468-471  
  Keywords Animals; Blood Bactericidal Activity/immunology; Circadian Rhythm; Cricetinae; Fever/immunology; Hypersensitivity, Delayed/immunology; *Immunity; Light/*adverse effects; Lipopolysaccharides; Locomotion; Phodopus/*immunology  
  Abstract Species have been adapted to specific niches optimizing survival and reproduction; however, urbanization by humans has dramatically altered natural habitats. Artificial light at night (LAN), termed 'light pollution', is an often overlooked, yet increasing disruptor of habitats, which perturbs physiological processes that rely on precise light information. For example, LAN alters the timing of reproduction and activity in some species, which decreases the odds of successful breeding and increases the threat of predation for these individuals, leading to reduced fitness. LAN also suppresses immune function, an important proxy for survival. To investigate the impact of LAN in a species naive to light pollution in its native habitat, immune function was examined in Siberian hamsters derived from wild-caught stock. After four weeks exposure to dim LAN, immune responses to three different challenges were assessed: (i) delayed-type hypersensitivity (DTH), (ii) lipopolysaccharide-induced fever, and (iii) bactericide activity of blood. LAN suppressed DTH response and reduced bactericide activity of blood after lipopolysaccharide treatment, in addition to altering daily patterns of locomotor activity, suggesting that human encroachment on habitats via night-time lighting may inadvertently compromise immune function and ultimately fitness.  
  Address Department of Neuroscience, The Ohio State University Medical Center, Columbus, OH 43210, USA. tracy.bedrosian@osumc.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1744-9561 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21270021; PMCID:PMC3097873 Approved no  
  Call Number IDA @ john @ Serial 90  
Permanent link to this record
 

 
Author (up) Ikeno, T.; Weil, Z.M.; Nelson, R.J. url  doi
openurl 
  Title Dim light at night disrupts the short-day response in Siberian hamsters Type Journal Article
  Year 2014 Publication General and Comparative Endocrinology Abbreviated Journal Gen Comp Endocrinol  
  Volume 197 Issue Pages 56-64  
  Keywords 2,4-dinitro-1-flourobenzene; Dnfb; Dth; Eya3; Eyes absent 3; GnIH; GnRH; Immune function; Ld; Lps; Light pollution; Pt; Pelage; Per1; Period1; Photoperiodism; Rfrp; RFamide-related peptide; Scn; Sd; Seasonality; Tsh; TSH receptor; Tshr; dLAN; delayed-type hypersensitivity; dim light at night; gonadotropin-inhibiting hormone; gonadotropin-releasing hormone; lipopolysaccharide; long days; pars tuberalis; short days; suprachiasmatic nuclei; thyroid-stimulating hormone  
  Abstract Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response.  
  Address Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA. Electronic address: randy.nelson@osumc.edu  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0016-6480 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:24362257 Approved no  
  Call Number IDA @ john @ Serial 82  
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