Overview of bone biology in the egg-laying hen
Overview of bone biology in the egg-laying hen
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DOI：
10.1093/ps/83.2.193
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发表时间：
2004-02-01
期刊：
影响因子：
4.4
通讯作者：
Whitehead, CC
中科院分区：
文献类型：
--
作者：
Whitehead, CC
在年轻的母鸡中，长骨通过软骨内生长而伸长。生长板软骨细胞增殖，然后肥大，并被形成骨小梁网络的成骨细胞所取代。随着骨的延长，这种骨逐渐被破骨细胞吸收。通过膜内骨化，长骨变宽，扁平骨形成，其中骨膜层中的成骨细胞形成皮质骨，伴有骨内膜内表面的骨吸收。结构性骨小梁和皮质骨类型的生长持续到母鸡性成熟开始。在这一点上，雌激素的大量激增改变了成骨细胞形成髓骨而不是结构骨的功能。髓骨是一种编织骨，作为蛋壳形成的钙的不稳定来源。它排列在结构骨上，也以骨针形式出现在骨髓腔内。它具有很小的固有强度，但可以有助于抗断裂性。破骨细胞吸收髓骨和结构骨，使得在母鸡保持生殖状态期间，整个骨骼中的结构骨逐渐丧失，这是骨质疏松症的特征。骨骼的脆弱性增加使它们更容易骨折。骨丢失的动力学可能受到许多营养、环境和遗传因素的影响。如果母鸡失去繁殖能力，雌激素水平下降，成骨细胞恢复结构性骨形成，骨骼再生可以发生。
In young pullets, long bones elongate by endochondral growth. Growth plate chondrocytes proliferate, then hypertrophy, and are replaced by osteoblasts that form a network of trabecular bone. This bone is gradually resorbed by osteoclasts as the bone lengthens. Long bones widen, and flat bones are formed, by intramembranous ossification in which cortical bone formation by osteoblasts in the periosteal layer is accompanied by osteoclastic resorption at the inner endosteal surface. Growth of structural trabecular and cortical bone types continues up to the onset of sexual maturity in pullets. At this point, the large surge in estrogen changes the function of osteoblasts to forming medullary bone rather than structural bone. Medullary bone is a woven bone that acts as a labile source of calcium for eggshell formation. It lines structural bone and also occurs as spicules within the marrow cavity. It has little inherent strength but can contribute to fracture resistance. Osteoclasts resorb both medullary and structural bone so that during the period the hen remains in reproductive condition there is a progressive loss of structural bone throughout the skeleton, which is characteristic of osteoporosis. The increasing fragility of the bones makes them more susceptible to fractures. The dynamics of bone loss can be affected by a number of nutritional, environmental, and genetic factors. If the hen goes out of reproductive condition, estrogen levels fall, osteoblasts resume structural bone formation, and skeletal regeneration can take place.