COLLAGEN IN OSTEOARTHRITIC CARTILAGE

建议的研究是针对理解1）的因素， 调节软骨细胞的分化状态，和2）激素 调节或软骨基质合成。 我们观察到 去分化的软骨细胞将返回到分化状态， 在琼脂糖悬浮培养中变为球形。 细胞骨架 参与表型转换表明，因为去分化 单层软骨细胞将重新表达分化的胶原表型 在用微生物破坏药物细胞松弛素B治疗后。 我们 将在一个依赖于微处理器的 软骨细胞中基因调控的途径。 我们假设 蛋白聚糖（PG）和胶原蛋白合成速率增加（8倍）， 发生在关节软骨切片的体外培养过程中是由于 每个细胞生长调节素受体数量增加。 之后 最初缺乏血清剂量反应，原始软骨细胞及其 琼脂糖、单层和切片培养物中的后代变得具有剂量响应性， 通过PG和DNA合成来测量。 将使用放射性标记的生长因子 以探测受体数量/细胞的平行增加。 如果我们能 了解这种细胞反应性增加的机制， 血清，我们可能能够增加骨关节炎中的基质合成， 大大减少蛋白多糖引起的软骨破坏 耗尽 这些研究将使用家兔肱骨关节 软骨和软骨细胞。 胶原蛋白表型将常规 通过SDS电泳和2-D CNBr肽图确定分离的 胶原蛋白 了解稳定软骨细胞的机制 表型和增强基质合成可能有助于设计 治疗策略，刺激抵抗的开始， 骨关节炎的进展。

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.