title: A high-fat diet increases body weight and circulating estradiol concentrations but does not improve bone structural properties in ovariectomized mice.
abstract: Bone health is influenced by body mass and estrogen. The objective of the study was to determine whether high-fat diet-induced obesity affects bone structure and alters markers of bone turnover in ovariectomized (OVX) mice. We hypothesized that a high-fat diet would increase body weight gain and serum estradiol levels in OVX mice but would not improve bone structural parameter in OVX mice. Thirty-five C57BL/6 mice were either sham operated or OVX at the age of 4 months and then fed either a normal-fat diet (10% energy as fat) or a high-fat diet (45% energy as fat with extra fat from lard) ad libitum for 11 weeks. Ovariectomy increased body weight, serum tartrate-resistant acid phosphatase concentration, and expression of cathepsin K in bone; decreased serum estradiol concentration; and induced significant bone loss manifested by decreased bone volume/total volume (BV/TV), connectivity density (Conn.D), trabecular number, and trabecular thickness with increased trabecular separation and structural model index (P < .01). The high-fat diet increased body weight (P < .01) in OVX mice and nonsignificantly decreased BV/TV (P = .08) and Conn.D (P = .10). Despite having similar serum estradiol concentrations and higher body weight, OVX mice consuming the high-fat diet had lower BV/TV, Conn.D, trabecular number, trabecular thickness, and higher structural model index and trabecular separation than did sham mice fed the normal-fat diet. These findings indicate that increased body weight and elevated serum estradiol concentration induced by a high-fat diet do not mitigate ovariectomy-induced bone loss in mice.
authors.affiliation: USDA, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58202, United States. Electronic address: Jay.Cao@ars.usda.gov.
authors.forename: Jay J
authors.initials: JJ
authors.lastname: Cao
authors.affiliation: USDA, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58202, United States.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Gregoire
mesh_terms: D000818:Animals; D015519:Bone Density / Q000502:physiology*; D004032:Diet; D059305:Diet, High-Fat; D004958:Estradiol / Q000097:blood*; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000209:etiology / Q000503:physiopathology; D010024:Osteoporosis / Q000503:physiopathology; D010052:Ovariectomy; D015430:Weight Gain
chemical_list: D004958:Estradiol
keywords: Bone structure; High-fat diet; Mice; Obesity; Ovariectomy