大鼠牙周膜牵张成骨过程中血管内皮生长因子和骨钙素的表达

Expression of vascular endothelial growth factor and osteocalcin during distraction osteogenesis of periodontal ligament on rats

目的建立大鼠牙周膜牵张成骨牙齿移动模型,探讨牙周膜牵张成骨过程中血管形成与骨形成的关系。方法将48只大鼠随机分成实验组和正畸对照组,所有动物拔除上颌右侧第一磨牙,正畸对照组按传统方法建立模型,对实验组上颌右侧第二磨牙近中牙槽骨实施减阻措施后安装牵张装置,分别在牵张开始后第0、3、5、10、20、30天每组随机处死4只动物,进行免疫组织化学染色,观察血管内皮生长因子(VEGF)和骨钙素(OC)随时间的表达变化。结果实验组VEGF阳性信号主要表达于血管内皮细胞、成纤维细胞、成骨细胞、破骨细胞以及骨细胞;VEGF的阳性表达在加力后逐渐增强,张力侧和压力侧分别在第10天和第5天达到峰值。OC阳性信号主要出现在牙周膜细胞外基质及成骨细胞中;张力侧与压力侧均在第10天达到峰值。正畸对照组VEGF和OC表达与实验组相似,但表达强度较低。结论 VEGF和OC参与了牙周膜牵张成骨牙齿快速移动过程中的牙周组织改建,具有重要意义。牙周膜牵张成骨中血管形成早于骨形成或二者同时发生。

Objective To establish animal models for research of orthodontic tooth under rapid movement through distraction osteogenesis of the periodontal ligament, and to approach the rules of bone formation and the relationship between new bone formation and angiogenesis. Methods 48 rats of which the right maxillary first molars were removed were randomly divided into experimental and orthodontic control group. The orthodontic model was established according to traditional method, and the stretch device was installed in the experimental group after reducing the second molar＇s mesial bone resistance. Four animals in each group were randomly selected to be killed at 6 time points （at day 0, 3, 5, 10, 20, and 30）. After specimens were obtained, immunohistochemical staining was done. The expression of vascular en- dothelial growth factor （VEGF） and osteocalcin （OC） were investigated. Results In the experimental group, VEGF was mainly expressed in vascular endothelial cells, fibroblasts, osteoblasts, osteoelasts, and bone cells. The positive expres- sion of VEGF gradually increased, the peak appeared at day 10 on the tension side, and the other side was at day 5. OC-positive signals were seen in the extracellular matrix of periodontal ligament and osteoblastic cells, and its peak appeared at day 10 on both tension and pressure side. The expression of VEGF and OC were similar in orthodontic control group, but the level was lower. Conclusion VEGF and OC involve in the remodeling of periodontal tissues and play an important role during periodontal ligament distraction osteogenesis. Angiogenesis is earlier than bone formation, or both appear simuhaneously.