title: Energy-restricted diet benefits body composition but degrades bone integrity in middle-aged obese female rats.
abstract: This study investigates the effects of a restricted diet (RD) on body composition and musculoskeletal health along with endocrines and molecular mechanism in established mature obese rats. Twenty female rats were fed with a high-fat diet (HFD) ad libitum for 4 months and then assigned to either HFD or RD group for another 4 months. Another 10 rats were on a low-fat diet for 8 months. Outcome measures included body composition, bone mineral density, microarchitecrure, and strength; serum leptin, adiponectin, insulin-like growth factor I, and liver glutathione peroxidase activity; and protein expression and spleen tumor necrosis factor α messenger RNA expression. We hypothesized that mature obese rats on a 35% energy restriction diet for 4 months would improve body composition but degrade microstructural and mechanical properties of long bones, and such changes in musculoskeletal integrity are related to the modulation of obesity-related endocrines and proinflammation. Relative to HFD, RD benefited body composition (decreased body weight and %fat mass and increased %fat-free mass); decreased insulin-like growth factor I and leptin; elevated adiponectin, glutathione peroxidase activity and protein expression and tumor necrosis factor α messenger RNA expression; and suppressed bone formation and increased bone resorption, resulting in decreased trabecular and cortical bone volume, bone mineral density, and bone strength. Relative to low-fat diet, RD had a similar effect on body composition and serum markers but increased bone turnover rate and decreased bone mineral density and strength. Our data suggest that long-term RD has a negative impact on bone remodeling in obese female rats, probably through modification of endocrines and elevation of proinflammation.
authors.affiliation: Department of Pathology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA. leslie.shen@ttuhsc.edu
authors.forename: Chwan-Li
authors.initials: CL
authors.lastname: Shen
authors.forename: Wenbin
authors.initials: W
authors.lastname: Zhu
authors.forename: Weimin
authors.initials: W
authors.lastname: Gao
authors.forename: Shu
authors.initials: S
authors.lastname: Wang
authors.forename: Lixia
authors.initials: L
authors.lastname: Chen
authors.forename: Ming-Chien
authors.initials: MC
authors.lastname: Chyu
mesh_terms: D052242:Adiponectin / Q000097:blood; D000818:Animals; D015415:Biomarkers / Q000097:blood; D001823:Body Composition; D015519:Bone Density; D001862:Bone Resorption / Q000209:etiology*; D001842:Bone and Bones / Q000378:metabolism / Q000503:physiopathology; D031204:Caloric Restriction / Q000009:adverse effects*; D018752:Diet, Fat-Restricted; D059305:Diet, High-Fat; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D020738:Leptin / Q000097:blood; D008099:Liver / Q000378:metabolism; D009765:Obesity / Q000150:complications / Q000178:diet therapy / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D011506:Proteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013154:Spleen / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D015431:Weight Loss / Q000502:physiology
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D020738:Leptin; D011506:Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D007334:Insulin-Like Growth Factor I; D005979:Glutathione Peroxidase
keywords: ANOVA; BFR/BS; BFR/BV; BIS; BMC; BMD; BS; BV; Body composition; Bone; Ct.Ar; Ct.Th; DXA; ECF; ES; ES/BS; Ec-BFR/BS; Ec-ES/BS; Ec-MS/BS; Energy restriction; FFM; FM; Female rat; GH; GPX; HFD; ICF; IGF-I; LFD; LSD; MAR; MS/BS; Musculoskeletal health; ObS/BS; Obesity; OcS/BS; PCR; Ps-BFR/BS; Ps-MAR; Ps-MS/BS; RD; T.Ar; TBW; TNF-α; TV; Tb.N; Tb.Sp; Tb.Th; analysis of variance; bioimpedance spectroscopy; bone formation rate/bone surface; bone formation rate/bone volume; bone mineral content; bone mineral density; bone surface; bone volume; cDNA; complementary DNA; cortical bone area; cortical thickness; dual-energy x-ray absorptiometry; endocortical bone formation rate; endocortical eroded surface/bone surface; eroded surface; eroded surface/bone surface; extracellular fluid; fat mass; fat-free mass; glutathione peroxidase; growth hormone; high-fat diet; insulin-like growth factor I; intracellular fluid; least significant difference; low-fat diet; mRNA; messenger RNA; mineral apposition rate; mineralizing surface; osteoblast surface per bone surface; osteoclast surface per bone surface; percent endocortical mineralized surface/bone surface; percent periosteal mineralized surface/bone surface; periosteal bone formation rate; periosteal mineral apposition rate; polymerase chain reaction; restricted diet; total body water; total bone area; total volume; trabecular number; trabecular separation; trabecular thickness; tumor necrosis factor α