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Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only Publication Acceptance Date: 11/15/2007 Publication Date: 4/15/2008 Citation: Cao, J.J. 2008. Relative bone mass decreased in mice fed high dietary fat despite an increase in body mass and bone formation markers [Abstract]. Journal of Federation of American Societies for Experimental Biology. 22:314.1. Interpretive Summary: Technical Abstract: Osteoporosis and obesity are interrelated health disorders. Osteoblasts and adipocytes are derived from common mesenchymal stem cells and age-related osteoporosis is associated with increased bone marrow adipogenesis. To determine whether bone mass and osteoblast number and activity are affected by dietary fat intake, six-week-old male C57BL/6 mice were randomly assigned to two groups (n=10-11/group) and fed either a high fat diet (HFD, 45% kcal as fat) or a low fat control diet (LFD, 10%) for 14 weeks. Bone marrow stromal cells (BMSCs) were cultured and bone architecture was evaluated by micro computed tomography. Mice fed HFD were 31% heavier (P<0.01) than those fed LFD, 41±6 vs. 31±2g, respectively. Higher numbers of alkaline phosphatase (ALP) positive colonies and calcium nodules were formed by BMSCs from HFD than from LFD mice (P<0.01). At d 14 of culture, ALP mRNA levels in BMSCs from HFD were higher (P<0.05) than from LFD mice. There were no significant differences in tibial fat-free weight, length, and mid-shaft diameter between the two groups (P>0.05). Although HFD increased total tibial volume by 14% as compared with LFD (2.05±0.15 vs. 1.80±0.29 mm3, respectively, P<0.05), bone volume relative to body mass decreased (8.5±1.8 vs. 11.2±3.4 mm3/kg, respectively). Our data suggest that feeding HFD results in bone resorption that exceeds any positive effect that increased body weight has on bone formation. |
