Studies on mechanisms of proliferation, differentiation and calcification of chondrocytes using established clonal cell lines.

1)利用小鼠肋骨生长软骨（GC）培养3年以上，建立了3株对甲状旁腺激素（PTH）反应性、碱性磷酸酶活性和内皮细胞生长抑制剂生成能力存在差异的克隆细胞系。德国/ Tl。17个细胞碱性磷酸酶活性高，具有钙化和表皮生长因子（EGF）受体的能力，对表皮生长因子、转化生长因子β反应良好。德国/ Tl。18个细胞对甲状旁腺激素反应良好，产生硫酸化因子。德国/ Tl。4个细胞产生内皮细胞生长因子和硫酸化因子。3个无性系的糖胺聚糖（Glycosaminoglycan， GAG）合成量明显低于原代培养的GC细胞。3株克隆系主要合成I型胶原。由于其不同的性质，这些细胞系将有助于软骨内成骨、甲状旁腺激素对骨骼细胞的作用和抗血管生成因子的研究。2)从人软骨肉瘤培养3年以上，建立了具有软骨表型的克隆细胞系。克隆系命名为HCS-2/8，形成了合成的软骨型蛋白聚糖和II型和XI型胶原蛋白，这是典型的软骨表型。与原代培养的兔肋软骨细胞一样，它们对胰岛素样生长因子I和II、转化生长因子β和视黄酸也有良好的反应。HCS-2/8细胞碱性磷酸酶活性低，在缺乏抗坏血酸时不发生钙化，但在维生素存在时酶活性显著增加。细胞产生碱性磷酸酶抑制剂和钙化抑制剂。由于这些特性，该细胞系可用于软骨内成骨的研究。

1) Three clonal cell lines with differences in responsiveness to parathyroid hormone (PTH), alkaline phosphatase activity and ability to produce an endothelial cell growth inhibitor(s) during more than 3 years in culture were established from growth cartilage (GC) of mouse ribs. MGC/Tl.17 cells had high activity of alkaline phosphatase, an ability to calcify and epidermal growth factor (EGF) receptors and responded well to epidermal growth factor, transforming growth factor beta. MGC/Tl.18 cells responded well to parathyroid hormone and produced sulfation factor. MGC/Tl.4 cells produced endothelial cell growth factor and sulfation factor. Glycosaminoglycan (GAG) syntheses in the three clonal lines were much lower than that of primary cultures of GC cells. The three clonal lines mainly synthesized type I collagen. Because of their different properties, these cell lines should be useful for studies on endochondral ossification, the actions of PTH on skeletal cells and anti-angiogenesis factors.2) A clonal cell line with cartilage phenotypes during more than 3 years in culture was established from a human chondrosarcoma. The clonal line, named HCS-2/8, formed synthesized cartilage-type proteoglycans and collagen types II and XI which are typical cartilage phenotypes. Like rabbit costal chondrocytes in primary culture, they also responded well to insulin-like growth factors I and II, transforming growth factor beta and retinoic acid. HCS-2/8 cells had low alkaline phosphatase activity and did not calcify in the absence of ascorbic acid but the enzyme activity increased markedly in the presence of the vitamin. The cells produced inhibitors of alkaline phosphatase and calcification. Because of these properties, the cell line should be useful for studies on endochondral ossification.