title: Chronic lipopolysaccharide infusion fails to induce depressive-like behaviour in adult male rats.
abstract: BACKGROUND
  Chronic inflammation is implicated in numerous diseases, including major depression and type 2 diabetes mellitus (T2DM). Since depression and T2DM often co-exist, inflammatory pathways are suggested as a possible link. Hence, the establishment of an immune-mediated animal model would shed light on mechanisms possibly linking depression and metabolic alterations.
  
  
  OBJECTIVE
  In this study we investigated a behavioural and metabolic paradigm following chronic infusion with low doses of lipopolysaccharide (LPS) using osmotic minipumps in male rats.
  
  
  METHODS
  Behavioural testing consisted of evaluating activity level in the open field and depressive-like behaviour in the forced swim test. Metabolic assessment included measurement of body weight, food and water intake, and glucose and insulin levels during an oral glucose tolerance test.
  
  
  RESULTS
  LPS-infused rats showed acute signs of sickness behaviour, but chronic LPS infusion did not induce behavioural or metabolic changes.
  
  
  CONCLUSIONS
  These results suggest that although inflammation is immediately induced as indicated by acute sickness, 4 weeks of chronic LPS administration via osmotic minipumps did not result in behavioural changes. Therefore, this paradigm may not be a suitable model for studying the underlying mechanisms that link depression and T2DM.
authors.affiliation: 1Translational Neuropsychiatry Unit,Aarhus University,Risskov,Denmark.
authors.forename: Christina Weide
authors.initials: CW
authors.lastname: Fischer
authors.affiliation: 1Translational Neuropsychiatry Unit,Aarhus University,Risskov,Denmark.
authors.forename: Nico
authors.identifier: http://orcid.org/0000-0001-9655-8911
authors.initials: N
authors.lastname: Liebenberg
authors.affiliation: 2The National Research Centre for the Working Environment,Copenhagen,Denmark.
authors.forename: Anne Mette
authors.initials: AM
authors.lastname: Madsen
authors.affiliation: 1Translational Neuropsychiatry Unit,Aarhus University,Risskov,Denmark.
authors.forename: Heidi Kaastrup
authors.initials: HK
authors.lastname: Müller
authors.affiliation: 3Medical Research Laboratory,Medical Department M (Endocrinology and Diabetes),Aarhus University Hospital,Denmark.
authors.forename: Sten
authors.initials: S
authors.lastname: Lund
authors.affiliation: 1Translational Neuropsychiatry Unit,Aarhus University,Risskov,Denmark.
authors.forename: Gregers
authors.initials: G
authors.lastname: Wegener
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D003863:Depression / Q000139:chemically induced* / Q000175:diagnosis / Q000378:metabolism / Q000523:psychology; D004195:Disease Models, Animal; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test / Q000379:methods; D007328:Insulin / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016207:Cytokines; D007328:Insulin; D008070:Lipopolysaccharides; D005947:Glucose
keywords: central nervous system; depression; neuroendocrinology; psychoneuroimmunology