周期性牵张力加载下人牙周膜细胞中血管内皮生长因子表达变化的研究

目的：观察周期性牵张力作用下，体外培养的人牙周膜成纤维细胞(human periodontal ligament fibroblasts，HPLFs)中血管内皮生长因子(Vascular endothelial growth factor，VEGF)表达的变化，以探讨机械力介导下牙周组织改建的机制。方法：通过体外细胞培养加载系统，采用周期性牵张力(每分钟6个循环，12％形变量)加载l、3、5、7d，用免疫组化和原位杂交技术，观察VEGF在HPLFs中的表达。结果：HPLFs在体外表达VEGF，其蛋白水平及mRNA水平的表达从加力ld开始升高，5d达到高峰，在加力7d开始下降。结论：在一定条件下，周期性牵张力可显著影响HPLFs VEGF的蛋白和mRNA水平的表达，进一步证实机械力作用下，VEGF参与了牙周组织改建，在正畸牙齿移动的机制中具有重要意义。

Expression of vascular endothelial growth factor in human periodontal ligament fibroblasts under cyclic strain

AIM:To observe the effects of the mechanical stretching force on the expression of vascular endothelial growth factor (VEGF) in human periodontal ligament fibroblasts (HPLFs) in vitro ,and to analyze the role of force during orthodontic periodontal tissue remodeling.METHODS:HPLFs were cultured on the elastic bottom plate and stimulated by cyclic strain (6cycle/min, 12%elongation) using mechanical loading system for cultured cells in vitro .RESUTLS:Loading cyclic strain significantly induced the expression of VEGF.Using immunohistochemical and in situ hybridization technique, we discovered that the expression of VEGF in HPLFs was time-dependent. Expression levels of VEGF protein and mRNA increased from the first day under mechanical stretching force and reached peak at the fifth day, and then decreased at the seventh day.CONCLSUION:The cyclic strain have an active effect on the expression of VEGF, suggesting that the VEGF may participate in the tissue remodeling during orthodontic tooth movement and especially played a more important role in orthodontic bone formation.