title: Eliminating animal facility light-at-night contamination and its effect on circadian regulation of rodent physiology, tumor growth, and metabolism: a challenge in the relocation of a cancer research laboratory.
abstract: Appropriate laboratory animal facility lighting and lighting protocols are essential for maintaining the health and wellbeing of laboratory animals and ensuring the credible outcome of scientific investigations. Our recent experience in relocating to a new laboratory facility illustrates the importance of these considerations. Previous studies in our laboratory demonstrated that animal room contamination with light-at-night (LAN) of as little as 0.2 lx at rodent eye level during an otherwise normal dark-phase disrupted host circadian rhythms and stimulated the metabolism and proliferation of human cancer xenografts in rats. Here we examined how simple improvements in facility design at our new location completely eliminated dark-phase LAN contamination and restored normal circadian rhythms in nontumor-bearing rats and normal tumor metabolism and growth in host rats bearing tissue-isolated MCF7(SR(-)) human breast tumor xenografts or 7288CTC rodent hepatomas. Reducing LAN contamination in the animal quarters from 24.5 ± 2.5 lx to nondetectable levels (complete darkness) restored normal circadian regulation of rodent arterial blood melatonin, glucose, total fatty and linoleic acid concentrations, tumor uptake of O(2), glucose, total fatty acid and CO(2) production and tumor levels of cAMP, triglycerides, free fatty acids, phospholipids, and cholesterol esters, as well as extracellular-signal-regulated kinase, mitogen-activated protein kinase, serine-threonine protein kinase, glycogen synthase kinase 3β, γ-histone 2AX, and proliferating cell nuclear antigen.
authors.affiliation: Department of Structural and Cellular Biology, Tulane University School of Medicine, Tulane, Louisiana, USA. rdauchy@tulane.edu
authors.forename: Robert T
authors.initials: RT
authors.lastname: Dauchy
authors.forename: Lynell M
authors.initials: LM
authors.lastname: Dupepe
authors.forename: Tara G
authors.initials: TG
authors.lastname: Ooms
authors.forename: Erin M
authors.initials: EM
authors.lastname: Dauchy
authors.forename: Cody R
authors.initials: CR
authors.lastname: Hill
authors.forename: Lulu
authors.initials: L
authors.lastname: Mao
authors.forename: Victoria P
authors.initials: VP
authors.lastname: Belancio
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Slakey
authors.forename: Steven M
authors.initials: SM
authors.lastname: Hill
authors.forename: David E
authors.initials: DE
authors.lastname: Blask
mesh_terms: D000047:Academies and Institutes / Q000592:standards*; D000818:Animals; D000830:Animals, Laboratory / Q000502:physiology; D001786:Blood Glucose / Q000378:metabolism; D001943:Breast Neoplasms / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D006528:Carcinoma, Hepatocellular / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D007753:Laboratories / Q000592:standards*; D008029:Lighting / Q000592:standards*; D008113:Liver Neoplasms / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D008297:Male; D008550:Melatonin / Q000097:blood; D009374:Neoplasms, Experimental / Q000098:blood supply / Q000378:metabolism* / Q000473:pathology*; D051381:Rats; D011915:Rats, Inbred BUF / Q000502:physiology*; D011923:Rats, Nude / Q000502:physiology*; D014183:Transplantation, Heterologous; D017132:Workplace
chemical_list: D001786:Blood Glucose; D008550:Melatonin