Differential growth by growth plates as a function of multiple parameters of chondrocytic kinetics
Differential growth by growth plates as a function of multiple parameters of chondrocytic kinetics
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DOI：
10.1002/jor.1100140613
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发表时间：
1996-11-01
影响因子：
2.8
通讯作者：
Barreto, C
中科院分区：
文献类型：
--
作者：
Wilsman, NJ;Farnum, CE;Barreto, C
生长板的差异性伸长是生长板软骨细胞将相同的基因调控序列翻译成给定伸长速率的适当时序模式的过程。虽然与差异生长相关的一些参数是已知的，但本研究的目的是检验涉及八个自变量的假设。我们通过考虑28日龄Long-Evans大鼠的四种不同生长板来验证这一假设。通过土霉素和溴脱氧尿苷标记技术提供时间参数。用标准技术测量体视学参数。对于所有四个生长板，每天产生的新软骨细胞的计算数量接近软骨-骨结合处每天损失的软骨细胞数量。这表明，拟议的方程和相关的变量代表了一套全面的变量定义差异增长。在绝对数量上，胫骨近端生长板每天产生的软骨细胞数量是桡骨近端生长板的四倍（16,400比3,700）。在胫骨近端，9%的增长是由细胞分裂; 32%，整个生长板的基质合成;和59%，肥大过程中的软骨细胞扩大。在生长板延长较慢的区域，细胞增大对延长的相对贡献从59%下降到44%，而基质合成的贡献从胫骨近端的32%增加到桡骨近端的49%。这项研究表明，差异生长是最好的描述为一个复杂的相互作用之间的细胞分裂，基质合成，细胞肥大。差异生长最好通过考虑一组八个独立变量来解释，其中七个因生长板而异。因此，这项研究证实了细胞肥大在伸长过程中的重要性，并增加了我们对控制生长板活动的局部介导的调节系统的重要性的理解。
Differential elongation of growth plates is the process by which growth-plate chondrocytes translate the same sequence of gene regulation into the appropriate timing pattern for a given rate of elongation. While some of the parameters associated with differential growth are known, the purpose of this study was to test the hypothesis that eight independent variables are involved. We tested this hypothesis by considering four different growth plates in 28-day-old Long-Evans rats. Temporal parameters were provided by means of oxytetracycline and bromodeoxyuridine labeling techniques. Stereological parameters were measured with standard techniques. For all four growth plates, the calculated number of new chondrocytes produced per day approximated the number of chondrocytes lost per day at the chondro-osseous junction. This suggests that the proposed equations and associated variables represent a comprehensive set of variables defining differential growth. In absolute numbers, the proximal tibial growth plate produced about four times as many chondrocytes per day as the proximal radial growth plate (16,400 compared with 3,700). In the proximal tibia, 9% of growth is contributed by cellular division; 32%, by matrix synthesis throughout the growth plate; and 59%, by chondrocytic enlargement during hypertrophy. In the more slowly elongating growth plates, the relative contribution to elongation from cellular enlargement decreases from 59 to 44%,with a relative increase in contribution from matrix synthesis ranging from 32% in the proximal tibia to 49% in the proximal radius. This study suggests that differential growth is best depicted as a complex interplay among cellular division, matrix synthesis, and cellular enlargement during hypertrophy. Differential growth is best explained by considering a set of eight independent variables, seven of which vary from growth plate to growth plate. Thus, this study confirms the importance of cellular hypertrophy during elongation and adds to our understanding of the importance of locally mediated regulatory systems controlling growth-plate activity.