Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario.
J Toxicol Environ Health A. 2009;72(20):1209-16. doi: 10.1080/15287390903127121.
A previous study showed that flaxseed (FS) combined with low-dose (LD) estrogen therapy, resembling LD transdermal estrogen therapy in postmenopaual women, inhibited loss of bone mineral density (BMD), bone mineral content (BMC), and strength in lumbar vertebrae in ovariectomized rats. Whether FS combined with an even lower dose of estrogen is effective at preserving bone or whether FS interferes with the effect of this lower dose of estrogen is unknown. Thus, this study determined whether an ultra-low-dose (ULD) estrogen therapy, half the dose previously studied, in combination with FS preserved bone mass and strength in the lumbar vertebrae in ovariectomized rats. Rats were treated for 12 wk with (1) basal diet (BD) (ovariectomized control), (2) BD + ULD estrogen implant, or (3) BD containing 10% FS + ULD estrogen implant. A sham-operated control group was fed BD. Unlike ULD, FS + ULD attenuated loss of BMD and strength at the lumbar vertebrae and BMD in femurs and tibias. FS + ULD resulted in higher percentages of n-3 fatty acids including alpha-linolenic acid and eicosapentaenoic acid and lower percentages of n-6 fatty acids including linoleic acid compared to all other groups. Differences in fatty acid composition at the lumbar vertebrae and tibia were significantly related to BMD, BMC, and strength. No treatment-induced effects on uterus weight were observed, but histological analyses are needed to confirm safety. In conclusion, FS did not antagonize the activity of ULD, and their combination attenuated the loss of BMD and strength at the lumbar vertebrae, which was associated with differences in bone fatty acid composition.
先前的研究表明,亚麻籽(FS)与低剂量(LD)雌激素联合治疗,类似于绝经后妇女的 LD 透皮雌激素治疗,可抑制去卵巢大鼠腰椎骨密度(BMD)、骨矿物质含量(BMC)和强度的丧失。FS 与甚至更低剂量的雌激素联合是否能有效保护骨骼,或者 FS 是否会干扰这种更低剂量雌激素的作用尚不清楚。因此,本研究旨在确定超低剂量(ULD)雌激素治疗(先前研究的剂量减半)与 FS 联合是否能保留去卵巢大鼠腰椎骨量和强度。大鼠用(1)基础饮食(BD)(去卵巢对照)、(2)BD+ULD 雌激素植入物或(3)BD 中含有 10% FS+ULD 雌激素植入物治疗 12 周。假手术对照组喂食 BD。与 ULD 不同,FS+ULD 减轻了腰椎 BMD 和强度以及股骨和胫骨 BMD 的丧失。FS+ULD 导致 n-3 脂肪酸(包括α-亚麻酸和二十碳五烯酸)的百分比增加,而 n-6 脂肪酸(包括亚油酸)的百分比降低,与所有其他组相比。腰椎和胫骨的脂肪酸组成差异与 BMD、BMC 和强度显著相关。未观察到治疗对子宫重量的影响,但需要组织学分析来确认安全性。总之,FS 没有拮抗 ULD 的活性,它们的组合减轻了腰椎 BMD 和强度的丧失,这与骨脂肪酸组成的差异有关。