YOUNG R W
J Cell Biol. 1962 Sep;14(3):357-70. doi: 10.1083/jcb.14.3.357.
Endochondral osteogenesis was studied autoradiographically in ribs and tibiae of 32 Long-Evans rats injected with 1 microc/gm H(3)-thymidine at 6 days of age and sacrificed at intervals between 1 hour and 2 weeks later. Proliferation and specialization of bone cells were studied by analyses of (a) the percentage of mitoses which were labeled, (b) the percentage of labeled nuclei in bone cells, and (c) grain counts. The following conclusions were derived: The various types of bone cells represent different functional states of the same cell. Cell division is usually restricted to cells in the morphologically unspecialized "osteoprogenitor" state. Specialized bone cells arise by modulation of osteoprogenitor cells. The average cell generation time is shortest in the metaphysis, longest in the periosteum, and intermediate in the endosteum. The average duration of DNA synthesis is relatively constant (about 8 hours). With increasing length of generation time there is a slight increase in G(2) + mitosis, but the major change is a lengthening of G(1). After dividing, cells in the osteoprogenitor state may remain within the progenitor pool or undergo modulation of cell type, specializing as osteoblasts or becoming incorporated in osteoclasts.
采用放射自显影术对32只长-伊文斯大鼠的肋骨和胫骨进行软骨内成骨研究。这些大鼠在6日龄时注射1微克/克的³H-胸腺嘧啶核苷，并于1小时至2周后的不同时间点处死。通过分析以下内容研究骨细胞的增殖和分化：（a）标记有丝分裂的百分比，（b）骨细胞中标记细胞核的百分比，以及（c）颗粒计数。得出以下结论：不同类型的骨细胞代表同一细胞的不同功能状态。细胞分裂通常局限于形态上未分化的“骨祖细胞”状态的细胞。特化的骨细胞由骨祖细胞的调节产生。平均细胞生成时间在干骺端最短，在骨膜最长，在内骨膜居中。DNA合成的平均持续时间相对恒定（约8小时）。随着生成时间的延长，G₂期+有丝分裂期略有增加，但主要变化是G₁期延长。骨祖细胞状态的细胞分裂后可能留在祖细胞池中，或经历细胞类型的调节，特化为成骨细胞或并入破骨细胞。
