Lee Yeon-Hee, Nahm Dong-Seok, Jung Youn-Kwan, Choi Je-Yong, Kim Sahng Gyoon, Cho Michael, Kim Myung-Hee, Chae Chang-Hoon, Kim Seong-Gon
Department of Orthodontics, College of Dentistry, Seoul National University, Seoul, Korea.
J Periodontol. 2007 Mar;78(3):446-52. doi: 10.1902/jop.2007.060240.
Compressive force is an important mechanical stimulus on the periodontal ligament (PDL) and is closely related to therapeutic tooth movement. In this study, early or late response genes related to the compressive stress in PDL cells were evaluated. Particularly, the expression of interleukin (IL)-6, IL-8, and alkaline phosphatase (ALP) was studied.
The primary cultured cells from PDL were grown in a three-dimensional collagen gel, and received a continuous static compressive force (1.76 g/cm(2)). The expressed genes were screened by cDNA microarray assays for 2 or 12 hours after the initiation of the mechanical force application. The genes of interest that showed significant changes in expression in the cDNA microarray assay were analyzed further by quantitative reverse transcriptase polymerase chain reaction (RT-PCR), enzyme-linked immunoabsorbent assays (ELISA), and ALP assays.
ALP, IL-6, and IL-8 were selected among the genes that significantly changed expression (/M/ >0.7) and subsequently were confirmed by quantitative RT-PCR. The secreted protein concentrations for IL-6, IL-8, and ALP activity were measured at 72 hours after application of continuous static compressive force. The protein level of IL-6 was significantly increased at 72 hours (P <0.001), but there was no significant change in IL-8 (P >0.05). ALP activity was decreased approximately 41.5% compared to the control (P = 0.015).
Considering that IL-6 is a potent osteoclast activator and the compressive side of PDL during orthodontic tooth movement shows the resorption of calcified tissue, the changed expression of IL-6 and ALP in response to the static compressive force in PDL cells may contribute to the orthodontic tooth movement or alveolar bone remodeling.
压力是牙周膜（PDL）上一种重要的机械刺激，与治疗性牙齿移动密切相关。在本研究中，评估了与PDL细胞中压力应激相关的早期或晚期反应基因。特别研究了白细胞介素（IL）-6、IL-8和碱性磷酸酶（ALP）的表达。
将PDL的原代培养细胞在三维胶原凝胶中培养，并施加持续静态压力（1.76 g/cm²）。在施加机械力后2或12小时，通过cDNA微阵列分析筛选表达的基因。对在cDNA微阵列分析中显示表达有显著变化的感兴趣基因，进一步通过定量逆转录聚合酶链反应（RT-PCR）、酶联免疫吸附测定（ELISA）和ALP测定进行分析。
在表达显著变化（/M/>0.7）的基因中选择了ALP、IL-6和IL-8，随后通过定量RT-PCR得到证实。在施加持续静态压力72小时后，测量IL-6、IL-8的分泌蛋白浓度和ALP活性。IL-6的蛋白水平在72小时时显著升高（P<0.001），但IL-8没有显著变化（P>0.05）。与对照组相比，ALP活性降低了约41.5%（P = 0.015）。
鉴于IL-6是一种有效的破骨细胞激活剂，且正畸牙齿移动过程中PDL的受压侧显示钙化组织吸收，PDL细胞中IL-6和ALP因静态压力而发生的表达变化可能有助于正畸牙齿移动或牙槽骨重塑。
