Ingram A J, Parbtani A, Clark W F, Spanner E, Huff M W, Philbrick D J, Holub B J
Department of Medicine, University of Western Ontario, London, Canada.
Am J Kidney Dis. 1995 Feb;25(2):320-9. doi: 10.1016/0272-6386(95)90015-2.
The objective of this study was to assess the effects of flaxseed and flax oil diets in the rat renal ablation model. Flaxseed is a rich source of alpha-linolenic acid, an 18:3n3 omega-3 fatty acid, which has anti-atherogenic and anti-inflammatory properties. Flaxseed, but not flax oil, is also rich in lignans, which are platelet-activating factor-receptor antagonists. Rats were subjected to 5/6 nephrectomy, fed a regular laboratory diet (RLD) for 1 week, then divided into three groups to receive either the RLD (n = 8), a 15% flaxseed diet (n = 8), or a 15% flax oil diet (n = 7). Blood pressure, proteinuria, glomerular filtration rate, and urinary prostaglandins (thromboxane B2 and 6-keto prostaglandin F1 alpha) were measured presurgery and at 1 week (before dietary allotment) and 20 weeks postnephrectomy when blood for plasma lipids and kidneys for histology and tissue-phospholipid analyses were obtained. Blood pressure increased progressively in the RLD group but not in the flax diet groups. Plasma triglycerides and cholesterol increased in all groups, but this increase was significantly attenuated by both flax diets. Proteinuria increased 1 week postsurgery and continued to increase in the RLD group but not in the flax diet groups. Glomerular filtration rate decreased progressively, but this decline in renal function was attenuated significantly by the flax diets. Both of the flax diets prevented glomerulosclerosis and mesangial expansion. Renal alpha-linolenic acid was increased by both the flax diets (flax oil > flaxseed), but eicosapentaenoic acid increased in the flax oil group only. The flaxseed group had greater renal-arachidonic acid levels than the flax oil and RLD groups. The total omega-3 fatty acids increased twofold to threefold in the flax oil group compared with the two other groups. The total saturated fatty acids were lower and the polyunsaturated fatty acids were increased in both flax diet groups. A progressive increase in urinary thromboxane B2 occurred in the RLD group but not in the flaxseed group; the level decreased in the flax oil group. The ratio of prostaglandin F1 alpha/thromboxane B2 was preserved in the flax oil group only. In conclusion, the dietary flax seed and flax oil attenuated the decline in renal function and reduced glomerular injury with favorable effects on blood pressure, plasma lipids, and urinary prostaglandins. While we have not proven any specific synergistic effects of the constituents of the flaxseed diet, the benefits of flax-derived alpha-linolenic acid with or without lignans in the rat-5/6 renal ablation model seem clear from this experiment.
本研究的目的是评估亚麻籽和亚麻油饮食对大鼠肾切除模型的影响。亚麻籽是α-亚麻酸的丰富来源，α-亚麻酸是一种18:3n3ω-3脂肪酸，具有抗动脉粥样硬化和抗炎特性。亚麻籽还富含木脂素，而亚麻油中不含木脂素，木脂素是血小板活化因子受体拮抗剂。对大鼠进行5/6肾切除术，给予常规实验室饮食（RLD）1周，然后分为三组，分别接受RLD（n = 8）、15%亚麻籽饮食（n = 8）或15%亚麻油饮食（n = 7）。在手术前、1周（饮食分配前）和肾切除术后20周测量血压、蛋白尿、肾小球滤过率和尿前列腺素（血栓素B2和6-酮前列腺素F1α），同时采集血液用于血浆脂质分析，采集肾脏用于组织学和组织磷脂分析。RLD组血压逐渐升高，而亚麻籽饮食组血压未升高。所有组的血浆甘油三酯和胆固醇均升高，但两种亚麻籽饮食均显著减轻了这种升高。蛋白尿在手术后1周增加，RLD组持续增加，而亚麻籽饮食组未增加。肾小球滤过率逐渐降低，但亚麻籽饮食显著减轻了肾功能的下降。两种亚麻籽饮食均预防了肾小球硬化和系膜扩张。两种亚麻籽饮食均使肾脏α-亚麻酸增加（亚麻油组>亚麻籽组），但只有亚麻油组的二十碳五烯酸增加。亚麻籽组的肾脏花生四烯酸水平高于亚麻油组和RLD组。与其他两组相比，亚麻油组的总ω-3脂肪酸增加了两倍至三倍。两种亚麻籽饮食组的总饱和脂肪酸较低，多不饱和脂肪酸增加。RLD组尿血栓素B2逐渐增加，而亚麻籽组未增加；亚麻油组水平降低。仅亚麻油组维持了前列腺素F1α/血栓素B2的比值。总之，饮食中的亚麻籽和亚麻油减轻了肾功能下降，减少了肾小球损伤，对血压、血浆脂质和尿前列腺素产生了有益影响。虽然我们尚未证明亚麻籽饮食成分有任何特定的协同作用，但从本实验来看，在大鼠5/6肾切除模型中，亚麻衍生的α-亚麻酸无论有无木脂素似乎都有明显益处。
