Ward Wendy E, Kim Susie, Chan Daphne, Fonseca Debbie
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
J Nutr Biochem. 2005 Dec;16(12):743-9. doi: 10.1016/j.jnutbio.2005.04.002. Epub 2005 Aug 10.
The extent of conversion of daidzein to its metabolite, equol, by intestinal microflora may be a critical step that determines if a diet rich in daidzein protects against the deterioration of bone after estrogen withdrawal. The objective was to determine the extent that daidzein is converted to equol. In addition, bone mineral content (BMC), bone mineral density (BMD) and strength of femurs and lumbar vertebrae (LV) in four mouse strains were measured. Mice were ovariectomized and fed control diet (AIN93G) with or without daidzein (200 mg daidzein/kg diet) for 3 weeks, after which serum, femurs and LV were collected. Serum daidzein and equol were elevated in all mice fed daidzein. Among mice fed daidzein, the CD-1 and Swiss-Webster (SW) mice had higher (P<.001) serum equol than C57BL/6 (C57) and C3H mice. Differences due to mouse strain were observed for all bone outcomes. C57 mice had lower femur BMC (P<.001), BMD (P<.001) and peak load at femur midpoint (P<.001) and neck (P<.001) than other mouse strains. C57 mice also had a lower femur midpoint yield load (P<.001) and resilience (P<.001) than C3H mice. C57 mice had a lower LV1-4 BMC (P<.001) and BMD (P<.001) compared with all mouse strains and peak load of LV3 was lower than CD-1 and SW mice. Differences in serum equol, BMD and bone strength properties should be considered when selecting a mouse strain for investigating whether dietary strategies that include isoflavones preserve bone tissue after ovariectomy.
肠道微生物群将大豆苷元转化为其代谢产物雌马酚的程度，可能是决定富含大豆苷元的饮食能否预防雌激素撤减后骨质恶化的关键步骤。目的是确定大豆苷元转化为雌马酚的程度。此外，还测量了四种小鼠品系股骨和腰椎的骨矿物质含量（BMC）、骨矿物质密度（BMD）及强度。对小鼠进行卵巢切除，喂食对照饮食（AIN93G），添加或不添加大豆苷元（200毫克大豆苷元/千克饮食），持续3周，之后收集血清、股骨和腰椎。所有喂食大豆苷元的小鼠血清中的大豆苷元和雌马酚均升高。在喂食大豆苷元的小鼠中，CD-1和瑞士韦伯斯特（SW）小鼠的血清雌马酚含量高于C57BL/6（C57）和C3H小鼠（P<0.001）。所有骨指标均观察到因小鼠品系不同而存在差异。与其他小鼠品系相比，C57小鼠的股骨BMC（P<0.001）、BMD（P<0.001）以及股骨中点（P<0.001）和颈部（P<0.001）的峰值负荷更低。C57小鼠的股骨中点屈服负荷（P<0.001）和弹性（P<0.001）也低于C3H小鼠。与所有小鼠品系相比，C57小鼠的腰椎1-4 BMC（P<0.001）和BMD（P<0.001）更低，且腰椎3的峰值负荷低于CD-1和SW小鼠。在选择小鼠品系以研究包括异黄酮在内的饮食策略是否能在卵巢切除后保护骨组织时，应考虑血清雌马酚、BMD和骨强度特性的差异。
