title: Non-invasive quantification of white and brown adipose tissues and liver fat content by computed tomography in mice.
abstract: OBJECTIVE
  Obesity and its distribution pattern are important factors for the prediction of the onset of diabetes in humans. Since several mouse models are suitable to study the pathophysiology of type 2 diabetes the aim was to validate a novel computed tomograph model (Aloka-Hitachi LCT-200) for the quantification of visceral, subcutaneous, brown and intrahepatic fat depots in mice.
  
  
  METHODS
  Different lean and obese mouse models (C57BL/6, B6.V-Lep(ob), NZO) were used to determine the most adequate scanning parameters for the detection of the different fat depots. The data were compared with those obtained after preparation and weighing the fat depots. Liver fat content was determined by biochemical analysis.
  
  
  RESULTS
  The correlations between weights of fat tissues on scale and weights determined by CT were significant for subcutaneous (r(2) = 0.995), visceral (r(2) = 0.990) and total white adipose tissue (r(2) = 0.992). Moreover, scans in the abdominal region, between lumbar vertebrae L4 to L5 correlated with whole-body fat distribution allowing experimenters to reduce scanning time and animal exposure to radiation and anesthesia. Test-retest reliability and measurements conducted by different experimenters showed a high reproducibility in the obtained results. Intrahepatic fat content estimated by CT was linearly related to biochemical analysis (r(2) = 0.915). Furthermore, brown fat mass correlated well with weighted brown fat depots (r(2) = 0.952). In addition, short-term cold-expose (4 °C, 4 hours) led to alterations in brown adipose tissue attributed to a reduction in triglyceride content that can be visualized as an increase in Hounsfield units by CT imaging.
  
  
  CONCLUSIONS
  The 3D imaging of fat by CT provides reliable results in the quantification of total, visceral, subcutaneous, brown and intrahepatic fat in mice. This non-invasive method allows the conduction of longitudinal studies of obesity in mice and therefore enables experimenters to investigate the onset of complex diseases such as diabetes and obesity.
authors.affiliation: Department of Experimental Nutrition, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany.
authors.forename: Marko
authors.initials: M
authors.lastname: Lubura
authors.forename: Deike
authors.initials: D
authors.lastname: Hesse
authors.forename: Nancy
authors.initials: N
authors.lastname: Neumann
authors.forename: Stephan
authors.initials: S
authors.lastname: Scherneck
authors.forename: Petra
authors.initials: P
authors.lastname: Wiedmer
authors.forename: Annette
authors.initials: A
authors.lastname: Schürmann
mesh_terms: D002001:Adipose Tissue, Brown / Q000000981:diagnostic imaging*; D052436:Adipose Tissue, White / Q000000981:diagnostic imaging*; D000818:Animals; D050218:Body Fat Distribution; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism; D005234:Fatty Liver / Q000175:diagnosis / Q000000981:diagnostic imaging*; D005260:Female; D021621:Imaging, Three-Dimensional / Q000379:methods; D008137:Longitudinal Studies; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese / Q000378:metabolism; D011860:Radiography, Abdominal / Q000379:methods; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods; D014280:Triglycerides / Q000378:metabolism
chemical_list: D014280:Triglycerides