title: Metabolic effects of chronic sleep restriction in rats.
abstract: OBJECTIVE
  Chronic partial sleep loss is associated with obesity and metabolic syndrome in humans. We used rats with lesions in the ventrolateral preoptic area (VLPO), which spontaneously sleep about 30% less than intact rats, as an animal model to study the consequences of chronic partial sleep loss on energy metabolism.
  
  
  METHODS
  Adult male Sprague-Dawley rats (300-365 g).
  
  
  METHODS
  We ablated the VLPO in rats using orexin-B-saporin and instrumented them with electrodes for sleep recordings. We monitored their food intake and body weight for the next 60 days and assessed their sleep-wake by 24-h EEG/EMG recordings on day 20 and day 50 post-surgery. On day 60, after blood samples were collected for metabolic profiling, the animals were euthanized and the brains were harvested for histological confirmation of the lesion site.
  
  
  RESULTS
  VLPO-lesioned animals slept up to 40% less than sham-lesioned rats. However, they showed slower weight gain than sham-lesioned controls, despite having normal food intake. An increase in plasma ghrelin and a decrease in leptin levels were observed, whereas plasma insulin levels remained unaffected. As expected from leaner animals, plasma levels of glucose, cholesterol, triglycerides, and C-reactive protein were reduced in VLPO-lesioned animals.
  
  
  CONCLUSIONS
  Chronic partial sleep loss did not lead to obesity or metabolic syndrome in rats. This finding raises the question whether adverse metabolic outcomes associated with chronic partial sleep loss in humans may be due to factors other than short sleep, such as circadian disruption, inactivity, or diet during the additional waking hours.
authors.affiliation: Department of Neurology, Program in Neuroscience and Division of Sleep Medicine, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
authors.forename: Ramalingam
authors.initials: R
authors.lastname: Vetrivelan
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Fuller
authors.forename: Shigefumi
authors.initials: S
authors.lastname: Yokota
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Clifford B
authors.initials: CB
authors.lastname: Saper
mesh_terms: D000818:Animals; D001786:Blood Glucose; D001835:Body Weight; D002097:C-Reactive Protein; D004734:Energy Metabolism; D054439:Ghrelin / Q000097:blood; D007328:Insulin / Q000097:blood; D020738:Leptin / Q000097:blood; D008055:Lipids / Q000097:blood; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D009765:Obesity / Q000097:blood*; D051381:Rats; D012892:Sleep Deprivation / Q000097:blood / Q000378:metabolism*; D015430:Weight Gain
chemical_list: D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin; D020738:Leptin; D008055:Lipids; D002097:C-Reactive Protein
keywords: Obesity; insomnia; metabolic syndrome; sleep restriction; ventrolateral preoptic area