Mitamura Rieko, Hara Hiroshi
Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-9, Nishi-9, Sapporo 060-8589, Japan.
Br J Nutr. 2005 Aug;94(2):268-74. doi: 10.1079/bjn20051483.
This study demonstrates that feeding difructose anhydride III (DFAIII) improves bone strength and femoral mineral concentrations in a rat model of oestrogen deficiency. We showed the relationship between Ca, Mg and P absorption and bone characteristics in rats. Two groups of female Sprague-Dawley rats (6 weeks old) underwent bilateral ovariectomy (ovariectomized rats, OVX rats) or bilateral laparotomy (sham rats). At 10 weeks old, OVX and sham rats were divided into three subgroups and fed a control, 1.5 % DFAIII or 3 % DFAIII diet for 8 weeks, respectively. Ca but not Mg absorption rates were lowered by ovariectomy; however, ingestion of the 1.5 % and 3 % DFAIII diets similarly restored the reduced Ca absorption in OVX rats at 4 and 8 weeks after feeding of the test diets. DFAIII increased Mg absorption dose-dependently in sham and OVX rats. The bone strength, femoral Ca and Mg concentrations, and distal bone mineral density in the 3 % DFAIII group were higher than those in the control group in OVX rats. The absorption rates of Ca and Mg were significantly correlated with femoral Ca and Mg concentrations and strength, which suggests that increasing both Ca and Mg absorption improves bone characteristics in OVX rats. There were no differences in any of the variables in the femur between the 1.5 % and 3 % DFAIII groups in OVX rats. In conclusion, feeding of a low dose of DFAIII increased intestinal Ca and Mg absorption, and the promotive effect of DFAIII persisted for over 8 weeks. This effect was associated with prevention of ovariectomy-induced osteopenia.
本研究表明,在雌激素缺乏的大鼠模型中,喂食二果糖酐III(DFAIII)可提高骨强度和股骨矿物质浓度。我们展示了大鼠体内钙、镁和磷吸收与骨骼特征之间的关系。两组6周龄雌性斯普拉格-道利大鼠分别接受双侧卵巢切除术(去卵巢大鼠,OVX大鼠)或双侧剖腹术(假手术大鼠)。10周龄时,将OVX大鼠和假手术大鼠分为三个亚组,分别喂食对照饮食、1.5% DFAIII饮食或3% DFAIII饮食,持续8周。卵巢切除术降低了钙的吸收率,但未降低镁的吸收率;然而,在喂食试验饮食4周和8周后,摄入1.5%和3% DFAIII饮食同样恢复了OVX大鼠降低的钙吸收。在假手术大鼠和OVX大鼠中,DFAIII剂量依赖性地增加了镁的吸收。在OVX大鼠中,3% DFAIII组的骨强度、股骨钙和镁浓度以及远端骨矿物质密度均高于对照组。钙和镁的吸收率与股骨钙和镁浓度及强度显著相关,这表明增加钙和镁的吸收可改善OVX大鼠的骨骼特征。在OVX大鼠中,1.5%和3% DFAIII组的股骨各项变量均无差异。总之,喂食低剂量DFAIII可增加肠道钙和镁的吸收,且DFAIII的促进作用持续超过8周。这种作用与预防卵巢切除术后的骨质减少有关。