Roach Helmtrud I, Mehta Gautam, Oreffo Richard O C, Clarke Nicholas M P, Cooper Cyrus
University Orthopaedics, Bone & Joint Research Group, University of Southampton, Southampton General Hospital, Southampton, United Kingdom.
J Histochem Cytochem. 2003 Mar;51(3):373-83. doi: 10.1177/002215540305100312.
Despite the continued presence of growth plates in aged rats, longitudinal growth no longer occurs. The aims of this study were to understand the reasons for the cessation of growth. We studied the growth plates of femurs and tibiae in Wistar rats aged 62-80 weeks and compared these with the corresponding growth plates from rats aged 2-16 weeks. During skeletal growth, the heights of the plates, especially that of the hypertrophic zone, reflected the rate of bone growth. During the period of decelerating growth, it was the loss of large hydrated chondrocytes that contributed most to the overall decrease in the heights of the growth plates. In the old rats we identified four categories of growth plate morphology that were not present in the growth plates of younger rats: (a). formation of a bone band parallel to the metaphyseal edge of the growth plate, which effectively sealed that edge; (b). extensive areas of acellularity, which were resistant to resorption and/or remodeling; (c). extensive remodeling and bone formation within cellular regions of the growth plate; and (d). direct bone formation by former growth plate chondrocytes. These processes, together with a loss of synchrony across the plate, would prevent further longitudinal expansion of the growth plate despite continued sporadic proliferation of chondrocytes.
尽管老龄大鼠的生长板仍然存在，但纵向生长不再发生。本研究的目的是了解生长停止的原因。我们研究了62 - 80周龄Wistar大鼠股骨和胫骨的生长板，并将其与2 - 16周龄大鼠相应的生长板进行比较。在骨骼生长过程中，生长板的高度，尤其是肥大区的高度，反映了骨生长速率。在生长减速期，大型水化软骨细胞的丢失对生长板高度的总体下降贡献最大。在老龄大鼠中，我们发现了四类年轻大鼠生长板中不存在的生长板形态：(a). 形成一条与生长板干骺端边缘平行的骨带，有效地封闭了该边缘；(b). 广泛的无细胞区域，这些区域抗吸收和/或重塑；(c). 生长板细胞区域内广泛的重塑和骨形成；以及(d). 以前的生长板软骨细胞直接形成骨。这些过程，连同生长板上同步性的丧失，将阻止生长板进一步纵向扩展，尽管软骨细胞仍有零星增殖。
