Changes in bone mineral density and microarchitecture with advancing age in the male apolipoprotein E knockout mice / 中华内分泌代谢杂志

ABSTRACT

Objective To study the changes of microarchitecture, bone mineral density (BMD) , and bone mineral content (BMC) in apolipoprtein E knockout( ApoE-/-) mice. Methods Male ApoE-/- mice at 15, 28, and 40-week of age and sex-age-matched wild-type (WT) mice were involved in the study. The trabecular and cortical bone microarchitecture were assessed by micro-CT( μCT) in the right distal femur. The total body BMD of the left femur was determined by dual-energy X-ray absorptiometry ( DXA). The relationships among BMD, microarchitecture, and BMC were analyzed. Results Compared with WT mice,the advancing age ApoE-/- mice showed an increased volumetric BMD (vBMD), tissue BMD (tBMD) , BMC, bone volume fraction (BV/TV), trabecular number (Tb. N ) , trabecular thickness (Tb. Th) with an decreased bone surface fraction ( BS/BV), trabecular separation (Tb. SP) , and the structure mode index (P <0. 05 ) in the cancellous bone of femur. The cortical bone microarchitecture parameters as inner perimeter, outer perimeter, cortical area, marrow area, total area and moment of inertia were also increased, but cortical BMD, cortical bone mineral content (C. BMC) and cortical thickness retained constant. At the age of 28 weeks,the total body BMD in ApoEE-/- mice revealed higher than WT mice (P<0. 05) and there was no changes in 15 and 40-week-old mice compared with the sex-age-matched controls. vBMD was positively correlated with BMC, BV/TV,Tb. Th, BS/BV, and C. BMC, with the correlation coefficients 0.955,0.944,0. 834,0.923, and 0.903 .respectively, and there was no correlation between vBMD and the other parameters. Conclusions ApoEE-/- mice display an increased bone mass, suggesting that ApoE has an important role in bone remodeling.