Rutherford R B, TrailSmith M D, Ryan M E, Charette M F
School of Dental Medicine, University of Connecticut, Farmington 06030.
Arch Oral Biol. 1992 Feb;37(2):139-45. doi: 10.1016/0003-9969(92)90009-w.
Platelet-derived growth factor (PDGF) and insulin-like growth factor-I (IGF-I) interact to stimulate proliferation of fibroblasts in culture. Glucocorticoids variably effect the response of cultured fibroblasts to polypeptide growth factors. This study determined the effects of dexamethasone on growth-factor stimulation of gingival, periodontal ligament and pulp fibroblast proliferation in vitro. Cultures of quiescent, low-passage, human fibroblasts were treated for varying periods of time with transforming growth factor-beta 2 (TGF-beta 2), PDGF and IGF-I: (1) alone, (2) in combination with each other, (3) singly plus dexamethasone, (4) in combination plus dexamethasone. Combinations of human, recombinant PDGF and IGF-I (10-1000 ng/ml) induced significantly higher rates of cell proliferation than either factor alone. Dexamethasone at doses ranging from 10(-5) to 10(-8) M substantially enhanced cell proliferation induced by these combinations and by PDGF without IGF-I but not IGF-I alone. By 6 days after a single application, 2-3 times as many cells were present in the PDGF and dexamethasone cultures as compared to PDGF without IGF-I. TGF-beta 2 specifically blocked the effects of dexamethasone added to PDGF-stimulated cells. Collagen and non-collagenous protein synthesis was not affected by the addition of PDGF and IGF-I with or without dexamethasone. These data suggest that dexamethasone may substitute for IGF-I in PDGF stimulation of cell proliferation.
血小板衍生生长因子（PDGF）和胰岛素样生长因子-I（IGF-I）相互作用，刺激培养的成纤维细胞增殖。糖皮质激素对培养的成纤维细胞对多肽生长因子的反应有不同影响。本研究确定了地塞米松对体外生长因子刺激牙龈、牙周膜和牙髓成纤维细胞增殖的影响。将静止的、传代次数少的人成纤维细胞培养物用转化生长因子-β2（TGF-β2）、PDGF和IGF-I处理不同时间：（1）单独处理，（2）相互联合处理，（3）单独加地塞米松处理，（4）联合加地塞米松处理。人重组PDGF和IGF-I（10 - 1000 ng/ml）的联合诱导的细胞增殖率显著高于单独使用任何一种因子。剂量范围为10^(-5)至10^(-8) M的地塞米松显著增强了这些联合处理以及PDGF（无IGF-I）诱导的细胞增殖，但对单独的IGF-I无此作用。单次应用后6天，与无IGF-I的PDGF培养物相比，PDGF和地塞米松培养物中的细胞数量多2 - 3倍。TGF-β2特异性阻断了添加到PDGF刺激细胞中的地塞米松的作用。添加或不添加地塞米松的PDGF和IGF-I对胶原蛋白和非胶原蛋白合成均无影响。这些数据表明，在地塞米松刺激细胞增殖过程中，地塞米松可能替代IGF-I发挥作用。
