Phenotypic modulation of fibroblasts and its application for periodontal regenerative therapy

我们研究了在成纤维细胞的多细胞层片形成过程中，纤维连接蛋白(FN)和基质蛋白在细胞外基质(ECM)中沉积与细胞增殖的相关性。用10%胎牛血清、抗坏血酸和转化生长因子-β处理培养至融合的正常人牙龈成纤维细胞6天。溴脱氧尿嘧啶核苷(BrdU)掺入实验显示，细胞周期的S期细胞在第2天增多，BrdU阳性细胞在第2天开始均匀分布于单层，第4、6天分布于多层细胞周围。在长达6天的时间里观察到了类似的结果。在整个培养过程中，Osteonectin/SPARC在细胞中检测到，而在ECM中未检测到。免疫定量检测显示，Tenascin-C在细胞内的沉积在第2天增加了6倍。因此，这些结果提示Tenascin-C在ECM中的沉积与密度依赖性生长受阻的成纤维细胞重新进入细胞周期有关。

We investigated the relevance of proliferation to the deposition of fibronectin (FN) and matricellular proteins into the extracellular matrix (ECM) during the formation of multiple cell-layer sheets of fibroblasts. Normal human gingival fibroblasts grown to confluence were treated with 10% fetal bovine serum, ascorbic acid, and transforming growth factor-β for 6 days. This treatment led to a 3-fold increase in cell numbers on day 6. Bromodeoxyuridine (BrdU) incorporation assays showed that cells in the S phase of the cell cycle increased on day 2. BrdU-positive cells were uniformly distributed through monolayers on day 2 and were localized around multiple cell-layers on days 4 and 6. FN and thrombospondin-1 were densely arranged into a pericellular ECM on day 0. Similar results were observed for up to 6 days. Osteonectin/SPARC was detected in cells, but not in the ECM throughout the culture periods. Tenascin-C was sparsely distributed between cells on day 0, and was densely deposited into a pericellular ECM on day 2. Quantitative immunoassays showed a 6-fold increase in tenascin-C deposition on day 2. Thus, these results suggest that the deposition of tenascin-C into the ECM is relevant to the reentry of density-dependent growth-arrested fibroblasts into the cell cycle.