Hyc Anna, Moskalewski Stanislaw, Osiecka-Iwan Anna
Department of Histology and Embryology, Medical University of Warsaw, Warsaw, Poland.
Folia Histochem Cytobiol. 2021;59(3):178-186. doi: 10.5603/FHC.a2021.0017. Epub 2021 Jul 30.
In endochondral ossification septoclasts and osteoclasts (also called chondroclasts) release growth factors deposited in non-calcified and calcified zones of the growth plate. They stimulate, within the metaphysis, initial stages of the bone formation. We have recently reported quantitation of several growth factors in calcified cartilage from calf costochondral junction. Data from the analogous human cartilage could possibly help to choose efficient combinations of growth factors for clinical applications, but the amount of the calcified cartilage needed for analysis of numerous growth factors would be difficult to collect. The estimation of growth factors expression in endochondral chondrocytes may, indirectly, indicate which of them play a leading role in the stimulation of osteoprogenitor cells in metaphysis. To test this hypothesis, we used rat chondrocytes to evaluate mRNA levels of several growth factors.
Chondrocytes were isolated from proliferative and hypertrophic zones of the epiphyseal cartilage forming costochondral junctions of inbred Lewis rats. The total RNA was isolated from chondrocytes and the level of mRNA for bone morphogenetic proteins 1-7 (BMP-1-7), vascular endothelial growth factor A (VEGF-A), basic fibroblast growth factor (bFGF), growth/differentiation factor 5 (GDF-5), NEL-like protein 1 (NELL-1), transforming growth factor beta 1 (TGF-b1), mesencephalic astrocyte-derived neurotrophic factor (MANF), connective tissue growth factor (CTGF), osteoclast-stimulating factor 1 (OSTF-1) and insulin-like growth factor 1 (IGF-1) was evaluated using real-time PCR method.
All studied factors were expressed. The highest level of mRNA was detected for CTGF, MANF, VEGF-A and TGF-b1. Expression was also quite high for BMP-1, BMP-2, BMP-5, BMP-6, BMP-7, IGF-1, GDF-5 and OSTF-1. Very low level of mRNA was detected for BMP-3, BMP-4 and NELL-1.
Chondrocytes from the proliferative and hypertrophic zones of the growth plate produce factors involved in the cartilage metabolism and bone formation. The determination of these growth factors in humans could help to choose their optimal composition necessary for stimulation of bone formation in clinical practice. In rat the best stimulation of bone formation would presumably be achieved with a mixture of BMP-2, BMP-5, BMP-6 and BMP-7.
在软骨内成骨过程中，破隔细胞和破骨细胞（也称为软骨破骨细胞）释放沉积在生长板非钙化区和钙化区的生长因子。它们在干骺端刺激骨形成的初始阶段。我们最近报道了对小牛肋软骨连接处钙化软骨中几种生长因子的定量分析。来自类似人类软骨的数据可能有助于选择用于临床应用的有效生长因子组合，但分析多种生长因子所需的钙化软骨量很难收集。估计软骨内软骨细胞中生长因子的表达可能间接表明哪些生长因子在刺激干骺端骨祖细胞方面起主导作用。为了验证这一假设，我们使用大鼠软骨细胞来评估几种生长因子的mRNA水平。
从近交系Lewis大鼠肋软骨连接处的骨骺软骨增殖区和肥大区分离软骨细胞。从软骨细胞中分离总RNA，并使用实时PCR方法评估骨形态发生蛋白1 - 7（BMP - 1 - 7）、血管内皮生长因子A（VEGF - A）、碱性成纤维细胞生长因子（bFGF）、生长/分化因子5（GDF - 5）、NEL样蛋白1（NELL - 1）、转化生长因子β1（TGF - b1）、中脑星形胶质细胞衍生的神经营养因子（MANF）、结缔组织生长因子（CTGF）、破骨细胞刺激因子1（OSTF - 1）和胰岛素样生长因子1（IGF - 1）的mRNA水平。
所有研究的因子均有表达。CTGF、MANF、VEGF - A和TGF - b1的mRNA水平最高。BMP - 1、BMP - 2、BMP - 5、BMP - 6、BMP - 7、IGF - 1、GDF - 5和OSTF - 1的表达也相当高。BMP - 3、BMP - 4和NELL - 1的mRNA水平非常低。
生长板增殖区和肥大区的软骨细胞产生参与软骨代谢和骨形成的因子。在人类中测定这些生长因子有助于选择临床实践中刺激骨形成所需的最佳组合。在大鼠中，可能用BMP - 2、BMP - 5、BMP - 6和BMP - 7的混合物能实现对骨形成的最佳刺激。
