Immunolocalization of FGF-2 and VEGF in rat periodontal ligament during experimental tooth movement

OBJECTIVE: This article aimed at identifying the expression of fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF) in the tension and pressure areas of rat periodontal ligament, in different periods of experimental orthodontic tooth movement. METHODS: An orthodontic force of 0.5 N was applied to the upper right first molar of 18 male Wistar rats for periods of 3 (group I), 7 (group II) and 14 days (group III). The counter-side first molar was used as a control. The animals were euthanized at the aforementioned time periods, and their maxillary bone was removed and fixed. After demineralization, the specimens were histologically processed and embedded in paraffin. FGF-2 and VEGF expressions were studied through immunohistochemistry and morphological analysis. RESULTS: The experimental side showed a higher expression of both FGF-2 and VEGF in all groups, when compared with the control side (P < 0.05). Statistically significant differences were also found between the tension and pressure areas in the experimental side. CONCLUSION: Both FGF-2 and VEGF are expressed in rat periodontal tissue. Additionally, these growth factors are upregulated when orthodontic forces are applied, thereby suggesting that they play an important role in changes that occur in periodontal tissue during orthodontic movement.

研究目的：本研究旨在探讨实验性正畸牙齿移动不同阶段，大鼠牙周韧带张力区与压力区中成纤维细胞生长因子-2（fibroblast growth factor-2, FGF-2）及血管内皮生长因子（vascular endothelial growth factor, VEGF）的表达特征。研究方法：选取18只雄性Wistar大鼠，对其右上颌第一磨牙施加0.5 N的正畸力，分别持续3天（I组）、7天（II组）及14天（III组）；以对侧同名第一磨牙作为空白对照。于上述预设时间点处死实验动物，摘除上颌骨并固定。经脱矿处理后，对标本进行组织学加工并石蜡包埋。采用免疫组织化学法与形态学分析，检测两种生长因子的表达水平。研究结果：与对照组相比，实验组各分组的成纤维细胞生长因子-2与血管内皮生长因子表达水平均显著升高（P < 0.05）；实验组内张力区与压力区的因子表达差异亦具有统计学意义。研究结论：成纤维细胞生长因子-2与血管内皮生长因子均在大鼠牙周组织中表达。此外，施加正畸力后，两种生长因子的表达均出现上调，提示其在正畸牙齿移动过程中牙周组织的改建过程中发挥重要作用。