DeGuire Jason R, Mak Ivy L, Lavery Paula, Agellon Sherry, Wykes Linda J, Weiler Hope A
School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada.
School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada.
Bone. 2015 Apr;73:42-50. doi: 10.1016/j.bone.2014.12.005. Epub 2014 Dec 15.
Age-related osteoporosis and sarcopenia are ascribed in part to reductions in anabolic hormones. Dietary conjugated linoleic acid (CLA) improves lean and bone mass, but its impact during androgen deficiency is not known. This study tested if CLA would attenuate the effects of orchidectomy (ORX)-induced losses of bone and lean tissue. Male guinea pigs (n=40; 70-72 weeks), were randomized into four groups: (1) SHAM+Control diet, (2) SHAM+CLA diet, (3) ORX+Control diet, (4) ORX+CLA diet. Baseline blood sampling and dual-energy X-ray absorptiometry (DXA) scans were conducted, followed by surgery 4 days later with the test diets started 7 days after baseline sampling. Serial blood sampling and DXA scans were repeated 2, 4, 8 and 16 weeks on the test diets. Body composition and areal BMD (aBMD) of whole body, lumbar spine, femur and tibia were measured using DXA. At week 16, muscle protein fractional synthesis rate (FSR), volumetric BMD (vBMD), microarchitecture and bone strength were assessed. Body weight declined after SHAM and ORX surgery, with slower recovery in the ORX group. Dietary CLA did not affect weight or lean mass, but attenuated gains in fat mass. Lean mass was stable in SHAM and reduced in ORX by 2 weeks with whole body and femur bone mineral content (BMC) reduced by 4 weeks; CLA did not alter BMC. By week 16 ORX groups had lower free testosterone and myofibrillar FSR, yet higher cortisol, osteocalcin and ionized calcium with no alterations due to CLA. ORX+Control had higher prostaglandin E2 (PGE2) and total alkaline phosphatase compared to SHAM+Control whereas ORX+CLA were not different from SHAM groups. Femur metaphyseal vBMD was reduced in ORX+CTRL with the reduction attenuated by CLA. Femur cortical thickness (Ct.Th.) and biomechanical strength were reduced and cortical porosity (Ct.Po.) elevated by ORX and attenuated by CLA. This androgen deficient model with a sarcopenic-osteoporotic phenotype similar to aging men responded to dietary CLA with significant benefits to femur density and strength.
与年龄相关的骨质疏松症和肌肉减少症部分归因于合成代谢激素的减少。膳食共轭亚油酸（CLA）可改善瘦体重和骨量，但其在雄激素缺乏期间的影响尚不清楚。本研究测试了CLA是否会减轻去势（ORX）诱导的骨和瘦组织损失的影响。雄性豚鼠（n = 40；70 - 72周）被随机分为四组：（1）假手术+对照饮食，（2）假手术+CLA饮食，（3）去势+对照饮食，（4）去势+CLA饮食。进行基线血液采样和双能X线吸收法（DXA）扫描，4天后进行手术，在基线采样7天后开始给予试验饮食。在试验饮食上分别于2、4、8和16周重复进行系列血液采样和DXA扫描。使用DXA测量全身、腰椎、股骨和胫骨的身体成分和骨面积密度（aBMD）。在第16周时，评估肌肉蛋白质分数合成率（FSR）、体积骨密度（vBMD）、微结构和骨强度。假手术和去势手术后体重下降，去势组恢复较慢。膳食CLA不影响体重或瘦体重，但减弱了脂肪量的增加。假手术组瘦体重稳定，去势组在2周时瘦体重减少，全身和股骨骨矿物质含量（BMC）在4周时降低；CLA未改变BMC。到第16周时，去势组游离睾酮和肌原纤维FSR较低，但皮质醇、骨钙素和离子钙较高，CLA未引起改变。与假手术+对照相比，去势+对照的前列腺素E2（PGE2）和总碱性磷酸酶较高，而去势+CLA与假手术组无差异。去势+对照的股骨干骺端vBMD降低，CLA减轻了这种降低。去势降低了股骨皮质厚度（Ct.Th.）和生物力学强度，增加了皮质孔隙率（Ct.Po.），CLA减轻了这些变化。这种具有类似于老年男性的肌肉减少性骨质疏松症表型的雄激素缺乏模型对膳食CLA有反应，对股骨密度和强度有显著益处。
