title: Temporal analysis of lipopolysaccharide-induced sickness behavior in virgin and lactating female rats.
abstract: OBJECTIVE
  Lipopolysaccharide (LPS), an endotoxin that originates from the cell wall of Gram-negative bacteria, activates the immune system to release proinflammatory cytokines and to induce sickness behavior. The present study sought to characterize the time-dependent effects of LPS on fever, body weight, and food and water consumption in female virgin and lactating rats exposed to an LPS dose previously reported to induce sickness behavior in pregnant female rats.
  
  
  METHODS
  Virgin female Wistar rats in the estrous phase and lactating female Wistar rats on the third day of lactation received 100 µg/kg LPS or saline solution. Tympanic temperature, body weight, and food and water consumption were assessed 0, 2, 24, 48, 72, 96, and 120 h after treatment.
  
  
  RESULTS
  In lactating female rats, tympanic temperature was attenuated compared with virgin females. Food consumption and body weight gain in both groups decreased, but lactating rats consumed more food than virgin rats. Water consumption increased at different time points.
  
  
  CONCLUSIONS
  LPS exposure induced several signs of sickness behavior, including decreases in food consumption and body weight gain, and induced adipsia in both virgin and lactating female rats. Because the time course and profile of fever varied between lactating and nonlactating animals, these responses appeared to depend on the physiological state of female animals.
authors.affiliation: Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo, Brazil.
authors.forename: Amanda
authors.initials: A
authors.lastname: Nascimento
authors.forename: Maria
authors.initials: M
authors.lastname: Bernardi
authors.forename: Vanessa
authors.initials: V
authors.lastname: Pecorari
authors.forename: Christina
authors.initials: C
authors.lastname: Massoco
authors.forename: Luciano
authors.initials: L
authors.lastname: Felicio
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D005260:Female; D055809:Illness Behavior / Q000187:drug effects / Q000502:physiology*; D007774:Lactation; D008070:Lipopolysaccharides / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008070:Lipopolysaccharides