Effects of high-fat diet on bone mineral density and microarchitecture in LDLR-/-mice

Abstract

Objective To investigate the effect of high-fat diet on bone calcium content, bone mineral density, and microarchitecture in low density lipoprotein receptor knockout(LDLR-/-) mice. Methods Thirteen LDLR-/- mice aged 11 weeks and 13 sex-age-matched C57BL/6J mice(WT)were divided into WT group with normal diet, WT group with high-fat diet, LDLR-/- group with normal diet, and LDLR-/- group with high-fat diet. All mice were sacrificed at 40 weeks of age and left tibias were harvested to analyze the bone mineral density and bone microarchitecture parameters. The right tibias were sampled for measurement of osteoporogeterin(OPG)and receptor activator of nuclear factor kappa-B ligand(RANKL)mRNA expressions using real-time PCR. Results LDLR-/- and high-fat diet significantly changed bone calcium content, bone microarchitecture parameters, and OPG/RANKL mRNA ratio(P<0.05). Compared with WT mice, LDLR-/-mice with high-fat diet showed a lower bone calcium content, along with correspondingly decreased parameters of bone microarchitecture(P<0.05). Compared with WT mice with normal diet, bone calcium content, tissue bone mineral density, and OPG/RANKL mRNA ratio were decreased in LDLR-/-mice with ordinary diet(P<0.01), while no change of other bone microarchitecture parameters was found. Conclusions High-fat diet results in decreased bone mass and damaged bone microarchitecture in LDLR-/- mice, which may be attributed to the down-regulation of OPG/RANKL mRNA ratio. (Chin J Endocrinol Metab, 2018, 34: 325-329) Key words: High fat diet; Low density lipoprotein receptor; Gene knockout; Bone mineral density; Bone microarchitecture