title: Influence of tail versus cardiac sampling on blood glucose and lipid profiles in mice.
abstract: Blood is collected during animal experimentation to measure haematological and metabolic parameters. It cannot be assumed that circulating blood has the same composition irrespective of its location, and indeed, differences in the composition of blood sampled from the arterial and venous compartments have been reported. Here we investigated whether blood collected by cardiac puncture (CP) versus that collected following removal of the distal 1 mm of the tail tip (TT) differs with respect to glucose and lipid profiles in male C57BL/6J mice at 4, 7, 20 and 28 weeks of age. Blood was first collected from the TT of unanaesthetized mice, which were then immediately anaesthetized using ketamine/xylazine, and a second blood sample was collected by CP. The CP glucose concentration was significantly higher than TT glucose by a positive bias averaging +80% (P < 0.01), irrespective of the age of the mice. Conversely, the concentrations of the CP lipids, including total cholesterol, high-density lipoprotein cholesterol and triglyceride were lower than TT lipids by a negative bias averaging -25% (P < 0.05). These observations highlight the difficulty in measuring and comparing metabolic parameters such as glucose and lipid between one blood compartment and another. They illustrate the need to standardize sampling sites, especially when repeated blood sampling is required.
authors.affiliation: Human Nutrition Unit, The University of Auckland, Auckland,  New Zealand.
authors.forename: Yih Kai
authors.initials: YK
authors.lastname: Chan
authors.forename: Paul F
authors.initials: PF
authors.lastname: Davis
authors.forename: Sally D
authors.initials: SD
authors.lastname: Poppitt
authors.forename: Xueying
authors.initials: X
authors.lastname: Sun
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Greenhill
authors.forename: Rita
authors.initials: R
authors.lastname: Krishnamurthi
authors.forename: Aneta
authors.initials: A
authors.lastname: Przepiorski
authors.forename: Anne-Thea
authors.initials: AT
authors.lastname: McGill
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: Krissansen
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D001800:Blood Specimen Collection / Q000379:methods*; D006321:Heart; D050356:Lipid Metabolism / Q000502:physiology; D008055:Lipids / Q000097:blood*; D008297:Male; D051379:Mice; D011677:Punctures / Q000379:methods / Q000662:veterinary*; D013623:Tail / Q000098:blood supply*
chemical_list: D001786:Blood Glucose; D008055:Lipids