COLLAGEN IN OSTEOARTHRITIC CARTILAGE

拟议的研究旨在了解1)以下因素 调节软骨细胞的分化状态，以及2)激素 调节或软骨基质合成。我们观察到， 去分化软骨细胞在以下情况下将恢复到分化状态 琼脂糖悬浮液培养时，菌体呈球形。细胞骨架 表明参与表型转换是因为去分化 单层软骨细胞将重新表达分化的胶原表型 在用破坏微丝的药物细胞松弛素B治疗后 将在依赖于微丝的 软骨细胞的基因调控途径。我们曾假设， 蛋白多糖(PG)和胶原合成速度提高(8倍)， 在关节软骨切片的体外培养过程中发生的是由于 每个细胞的生长抑素受体数量增加。在此之后 初始缺乏血清剂量反应，原始软骨细胞及其 在琼脂糖、单层和切片培养中的子代变得剂量反应 通过PG和DNA合成来测量。将使用放射性标记的生长因子 探索受体数目/细胞的平行增加。如果我们可以 了解这种细胞反应性增加的机制 血清WE可能能够增加骨关节炎患者的基质合成和 大大减少蛋白多糖对软骨的破坏 耗尽。这些研究将在兔的肱骨关节上进行 软骨和软骨细胞。胶原蛋白的表型将是例行公事 用十二烷基硫酸钠凝胶电泳法和二维CNBR肽图测定 胶原蛋白。了解稳定软骨细胞的机制 表型和增强的基质合成可能有助于设计 刺激对启动和启动的抵抗的治疗策略 骨性关节炎的进展。

The proposed research is directed toward understanding 1) the factors which modulate the differentiated state of chondrocytes, and 2) the hormonal regulation or cartilage matrix synthesis. We have observed that dedifferentiated chondrocytes will return to the differentiated state if changed to spherical shape in agarose suspension culture. Cytoskeletal involvement in phenotypic switching is indicated because dedifferentiated monolayer chondrocytes will reexpress the differentiated collagen phenotype after treatment with the microfilament-disruptive drug, cytochalasin B. We will document and expand this information on a microfilament-dependent pathway for gene regulation in chondrocytes. We have hypothesized that the increased rate of proteoglycan (PG) and collagen synthesis (8-fold) that occurs during in vitro culture of articular cartilage slices is due to an increase in the number of somatomedin receptors per cell. Following an initial lack of serum dose response, original chondrocytes and their progeny in agarose, monolayer, and slice cultures become dose responsive as measured by PG and DNA synthesis. Radiolabeled growth factors will be used to probe for parallel increases in receptor number/cell. If we can understand the mechanism of this increase in cellular responsiveness to serum we may be able to increase matrix synthesis in osteoarthritis and greatly decrease the cartilage destruction that follows proteoglycan depletion. These studies will be performed with rabbit humeral articular cartilage and chondrocytes. Collagen phenotypes will be routinely determined by SDS electrophoresis and 2-D CNBr peptide maps of isolated collagens. Understanding the mechanism that stabilize the chondrocyte phenotype and enhance matrix synthesis may facilitate the design of therapeutic strategies that stimulate resistance to the initiation and progression of osteoarthritis.