title: Uncoupling protein-2 mRNA expression in mice subjected to intermittent hypoxia.
abstract: OBJECTIVE
  To investigate the effect of intermittent hypoxia-a model of obstructive sleep apnea (OSA)-on pancreatic expression of uncoupling protein-2 (UCP2), as well as on glycemic and lipid profiles, in C57BL mice.
  
  
  METHODS
  For 8 h/day over a 35-day period, male C57BL mice were exposed to intermittent hypoxia (hypoxia group) or to a sham procedure (normoxia group). The intermittent hypoxia condition involved exposing mice to an atmosphere of 92% N and 8% CO2 for 30 s, progressively reducing the fraction of inspired oxygen to 8 ± 1%, after which they were exposed to room air for 30 s and the cycle was repeated (480 cycles over the 8-h experimental period). Pancreases were dissected to isolate the islets. Real-time PCR was performed with TaqMan assays.
  
  
  RESULTS
  Expression of UCP2 mRNA in pancreatic islets was 20% higher in the normoxia group than in the hypoxia group (p = 0.11). Fasting serum insulin was higher in the hypoxia group than in the normoxia group (p = 0.01). The homeostasis model assessment of insulin resistance indicated that, in comparison with the control mice, the mice exposed to intermittent hypoxia showed 15% lower insulin resistance (p = 0.09) and 21% higher pancreatic β-cell function (p = 0.01). Immunohistochemical staining of the islets showed no significant differences between the two groups in terms of the area or intensity of α- and β-cell staining for insulin and glucagon.
  
  
  CONCLUSIONS
  To our knowledge, this is the first report of the effect of intermittent hypoxia on UCP2 expression. Our findings suggest that UCP2 regulates insulin production in OSA. Further study of the role that UCP2 plays in the glycemic control of OSA patients is warranted.
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Luciana Rodrigues
authors.initials: LR
authors.lastname: Vieira
authors.affiliation: School of Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Denis
authors.initials: D
authors.lastname: Martinez
authors.affiliation: Faculdade Anhanguera de Pelotas, Pelotas, Brazil.
authors.forename: Luiz Felipe
authors.initials: LF
authors.lastname: Forgiarini
authors.affiliation: Lutheran University of Brazil, Canoas, Brazil.
authors.forename: Darlan Pase da
authors.initials: DP
authors.lastname: Rosa
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Gustavo Alfredo Ochs de
authors.initials: GA
authors.lastname: Muñoz
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Micheli
authors.initials: M
authors.lastname: Fagundes
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Emerson Ferreira
authors.initials: EF
authors.lastname: Martins
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Carolina Caruccio
authors.initials: CC
authors.lastname: Montanari
authors.affiliation: Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Cintia Zappe
authors.initials: CZ
authors.lastname: Fiori
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology; D007333:Insulin Resistance; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D020181:Sleep Apnea, Obstructive / Q000378:metabolism* / Q000503:physiopathology; D000071246:Uncoupling Protein 2
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; D012333:RNA, Messenger; C000604390:Ucp2 protein, mouse; D000071246:Uncoupling Protein 2