Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749, Korea.
Mol Cells. 2011 Aug;32(2):189-96. doi: 10.1007/s10059-011-0071-1. Epub 2011 May 12.
Orthodontic force causes gradual compression of the periodontal ligament tissues, which leads to local hypoxia in the compression side of the tissues. In this study, we investigated whether antioxidants exert a regulatory effect on two factors: the expression of pro-inflammatory cytokines in human periodontal ligament fibroblasts (PDLFs) that were exposed to mechanical compression and hypoxia and the rate of orthodontic tooth movement in rats. Exposure of PDLFs to mechanical compression (0.5-3.0 g/cm(2)) or hypoxic conditions increased the production of intracellular reactive oxygen species. Hypoxic treatment for 24 h increased the mRNA levels of IL-1β, IL-6 and IL-8 as well as vascular endothelial growth factor (VEGF) in PDLFs. Resveratrol (10 nM) or N-acetylcysteine (NAC, 20 mM) diminished the transcriptional activity of hypoxiainducible factor-1 and hypoxia-induced expression of VEGF. Combined treatment with mechanical compression and hypoxia significantly increased the expression levels of IL-1β, IL-6, IL-8, TNF-α and VEGF in PDLFs. These levels were suppressed by NAC and resveratrol. The maxillary first molars of rats were moved mesially for seven days using an orthodontic appliance. NAC decreased the amount of orthodontic tooth movement compared to the vehicle-treated group. The results from immunohistochemical staining demonstrated that NAC suppressed the expression of IL-1β and TNF-α in the periodontal ligament tissues compared to the vehicle-treated group. These results suggest that antioxidants have the potential to negatively regulate the rate of orthodontic tooth movement through the down-regulation of pro-inflammatory cytokines in the compression sides of periodontal ligament tissues.
正畸力导致牙周韧带组织逐渐受压，导致组织受压侧局部缺氧。在这项研究中，我们研究了抗氧化剂是否对两个因素有调节作用：暴露于机械压缩和缺氧条件下的人牙周韧带成纤维细胞（PDLFs）中促炎细胞因子的表达和大鼠正畸牙移动的速度。PDLFs 暴露于机械压缩（0.5-3.0 g/cm(2)) 或低氧条件下会增加细胞内活性氧的产生。低氧处理 24 小时会增加 PDLFs 中 IL-1β、IL-6 和 IL-8 以及血管内皮生长因子（VEGF）的 mRNA 水平。白藜芦醇（10 nM）或 N-乙酰半胱氨酸（NAC，20 mM）降低了缺氧诱导因子-1 的转录活性和缺氧诱导的 VEGF 表达。机械压缩和缺氧的联合处理显著增加了 PDLFs 中 IL-1β、IL-6、IL-8、TNF-α 和 VEGF 的表达水平。NAC 和白藜芦醇抑制了这些水平。使用正畸矫治器将大鼠上颌第一磨牙向近中移动七天。与载体处理组相比，NAC 减少了正畸牙移动的量。免疫组织化学染色的结果表明，与载体处理组相比，NAC 抑制了牙周韧带组织中 IL-1β 和 TNF-α 的表达。这些结果表明，抗氧化剂通过下调牙周韧带组织受压侧的促炎细胞因子，有可能负调控正畸牙移动的速度。
