Seidlová-Wuttke Dana, Jarry Hubertus, Jäger Yvonne, Wuttke Wolfgang
Department of Obstetrics and Gynecology, Division of Clinical and Experimental Endocrinology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
J Bone Miner Metab. 2008;26(4):321-7. doi: 10.1007/s00774-007-0838-9. Epub 2008 Jul 4.
The development of bone in immature rats and in aged rats has not been thoroughly studied. Therefore, we investigated the development of bones in young, middle-aged, and aged female rats. Because most rat chows contain soy proteins, including estrogenic isoflavones, as a source of protein, comparison of effects on mineral density and on areas of the cancellous and cortical parts of the metaphysis of the tibia as measured by quantitative computer tomography in animals fed with soy-free and soy-containing food was made. As surrogate parameters of bone metabolism serum, osteocalcin (OC) and the breakdown products of bone collagen--the Crosslaps--were also determined. The cancellous density increased between day 25 after birth to reach peak bone mass at 90 days of age; in 18-and 20-month-old animals, significant reduction was observed that was more profound in the animals fed with soy-free food. Serum OC and the Crosslaps were highest in 15-day-old and lowest in 9-, 18-, and 20-month-old animals. Animals fed with soy-containing food had significantly higher osteocalcin levels at day 15 and at 9 and 18 months of age. In the aged animals, intake of soy isoflavones that have an estrogenic effect appears to exert beneficial effects as these aged animals lost less cancellous bone, as indicated by their surrogate parameters of metabolism in the serum. It is concluded that exorbitantly high bone turnover is present in immature and peripubertal rats. Raising and keeping female rats under soy-free or soy-containing conditions has marked effects on several bone parameters that are of particular relevance in aged animals.
未成熟大鼠和老年大鼠骨骼的发育尚未得到充分研究。因此，我们研究了幼年、中年和老年雌性大鼠骨骼的发育情况。由于大多数大鼠饲料都含有大豆蛋白，包括具有雌激素活性的异黄酮作为蛋白质来源，因此我们比较了在喂食不含大豆和含大豆食物的动物中，定量计算机断层扫描测量的胫骨干骺端松质骨和皮质骨部分的矿物质密度及面积的影响。作为骨代谢的替代参数，还测定了血清骨钙素（OC）和骨胶原分解产物——交联羧基末端肽（Crosslaps）。出生后第25天至90日龄时松质骨密度增加，达到峰值骨量；在18和20月龄的动物中，观察到显著降低，在喂食不含大豆食物的动物中更为明显。血清OC和Crosslaps在15日龄时最高，在9、18和20月龄动物中最低。喂食含大豆食物的动物在15日龄以及9和18月龄时骨钙素水平显著更高。在老年动物中，摄入具有雌激素作用的大豆异黄酮似乎发挥了有益作用，因为这些老年动物松质骨丢失较少，血清代谢替代参数表明了这一点。结论是未成熟和青春期前大鼠存在过高的骨转换。在不含大豆或含大豆的条件下饲养和维持雌性大鼠，对老年动物中几个特别相关的骨参数有显著影响。
