颞下颌关节髁突软骨细胞体外培养中去分化现象研究

目的　研究去分化髁状突软骨细胞的细胞生物学特性。方法　连续在体外贴壁条件下培养传代正常乳兔髁突软骨细胞至第 2 0代 ,观察培养细胞的形态变化 ,免疫组化法和RT -PCR法对传代过程中的数代细胞对II型胶原与蛋白多糖聚糖体的表达情况进行连续检测 ,观察细胞软骨基质蛋白表达分泌的变化以及发生明显去分化软骨细胞的超微结构特点。结果　在贴壁培养条件下 ,髁状突软骨细胞去分化现象于细胞传代第 3代后逐渐显著 ,第 6代后培养的软骨细胞几乎完全去分化。去分化细胞胞体拉长 ,呈“成纤维细胞”样外观。去分化过程中 ,细胞对软骨基质蛋白的表达水平逐渐降低 ,细胞增殖速度增强。透射电镜观察显示 ,去分化软骨细胞细胞核明显呈分叶状 ,表现出异型核。结论　髁突软骨细胞在体外贴壁培养传代过程中会发生去分化现象 ,丧失软骨细胞特征性细胞表型。

Study on dedifferentiation of condyle chondrocytes of temporomandibular joint

Objective To study the cell biological characteristics of dedifferentiated condyle chondrocytes.Methods The normal mandibular condylar chondrocytes from newborn rabbit were cultured and subcultivated in monolayer condition until the 20th passage.The morphological changes were observed and the expression of collagen type II and aggrecan by the cells during the subculture were studied with immunohistological staining and RT-PCR technique.The ultrastructure alterations were described for the dedifferentiated chondrocytes by transmission electron microscope.Results The condylar chondrocytes on monolayer culture showed obvious dedifferentiation after the third generation and almost all chondrocytes tended to dedifferentiation after the sixth generation.The dedifferentiated condylar chondrocytes exhibited the elongated shape,like fibroblasts.During the dedifferentiation,the expression level of cartilage matrix proteins by the chondrocyte subcultures gradually decreased,while the proliferation potential of the cells increased.Ultrastructure study showed the foliage-shaped nucleolus of the dedifferentiated chondrocytes.Conclusion During subcultivation in monolayer condition,chondrocytes dedifferentiated and lost the typical phenotype.