Ward W E, Yuan Y V, Cheung A M, Thompson L U
Department of Nutritional Sciences, University of Toronto, Toronto, Ontario M5S 3E2, Canada.
Br J Nutr. 2001 Oct;86(4):499-505. doi: 10.1079/bjn2001429.
Due to the potential oestrogenic effects of secoisolariciresinol diglycoside (SDG), the mammalian lignan precursor in flaxseed (Linum usitatissimum), we hypothesized that exposure to purified SDG during early life would have a positive effect on developing bone. This present study determined whether exposure to SDG purified from flaxseed during suckling via mother's milk or continuously to adolescence (postnatal day (PND) 50) or adulthood (PND 132) increased bone mineral content (BMC) or bone strength in female rat offspring. Offspring were exposed to basal diet (BD) or one of two doses of SDG (50S, 100S) equivalent to that in a 50 or 100 g flaxseed/kg diet during lactation only or through to PND 50 or 132. At PND 50 and 132, femurs were analysed for BMC by dual energy X-ray absorptiometry and biomechanical strength by a 3-point bending test. Compared with BD group, rats exposed to continuous 50S or 100S diet had stronger femurs at PND 50 without changes in BMC. At PND 132 there were no differences in femur strength despite the fact that continuous exposure to BD resulted in a higher BMC than rats exposed to 100S during lactation only or to 50S or 100S during lactation through to adulthood. In conclusion, female rat bone is more sensitive to the oestrogen-like action of lignans during early life when endogenous levels of sex hormones are low, but by adulthood the improved bone strength does not persist. Importantly, exposure to purified lignan does not have negative effects on bone strength.
由于开环异落叶松脂素二葡萄糖苷（SDG）具有潜在的雌激素样作用，它是亚麻籽（亚麻）中的哺乳动物木脂素前体，我们推测在生命早期接触纯化的SDG会对骨骼发育产生积极影响。本研究确定了在哺乳期通过母乳接触从亚麻籽中纯化的SDG，或持续接触至青春期（出生后第50天，PND 50）或成年期（PND 132），是否会增加雌性大鼠后代的骨矿物质含量（BMC）或骨强度。后代仅在哺乳期或直至PND 50或132时，接触基础饮食（BD）或两种剂量的SDG（50S、100S）之一，这两种剂量相当于50或100克亚麻籽/千克饮食中的含量。在PND 50和132时，通过双能X射线吸收法分析股骨的BMC，并通过三点弯曲试验分析生物力学强度。与BD组相比，持续接触50S或100S饮食的大鼠在PND 50时股骨更强壮，而BMC没有变化。在PND 132时，股骨强度没有差异，尽管持续接触BD导致的BMC高于仅在哺乳期接触100S或在哺乳期至成年期接触50S或100S的大鼠。总之，在生命早期，当内源性性激素水平较低时，雌性大鼠的骨骼对木脂素的雌激素样作用更敏感，但到成年期，骨强度的改善并不持续。重要的是，接触纯化的木脂素对骨强度没有负面影响。
