Zhang Yan-xiao, Zhou Hong, Wang Xiao-rong
Department of Orthodontics, the Affiliated Stomatological Hospital, Medical School of Xi'an Jiaotong University. Xi'an 710004, Shanxi Province, China.
Shanghai Kou Qiang Yi Xue. 2011 Apr;20(2):141-6.
To establish an animal model of orthodontic rapid tooth movement through distraction osteogenesis of the periodontal ligament and assess the cell proliferation including osteoblasts, osteoclasts and bone cells.
Forty rats were randomly divided into experimental and orthodontic control group, and received BrdU injection at the beginning of distraction intraperiotoneally. Traditional orthodontic model was established in the control group. In the experimental group, after some parts of mesial alveolar bone of the upper right second molar grinded, self-made distraction device was installed between the second molar and central incisors, the distraction frequency was 1mm/2d , and after one week , there would be a consolidation phase. Four animals in each group were randomly selected to be sacrificed at 5 time points. After obtaining specimens, immunohistochemical examination was done. Then BrdU labeled cells were observed in the regenerated tissue specimens and the positive cells were counted and analyzed with paired-samples t test by SPSS 16.0 software package.
BrdU positive cells were found in both tension and pressure sides, mainly bone cells, osteoblasts, osteoclasts and fibroblasts. BrdU-positive fibroblasts and osteoblasts reached a peak at day 10, and the expression at day 5 and 10 in the experimental group was higher than in the orthodontic treatment group. Osteoclasts reached a peak at day 20, but in the orthodontic treatment group it reached a peak at day 5. The number of positive bone cells was gradually rising over time, but the expression in the orthodontic treatment group was lower than that in the experimental group at day 20 and 30.
Intramembranous ossification is the main pattern during periodontal ligament distraction osteogenesis; Active bone remodeling occurs at the early and middle consolidation, new bone formation is ongoing, and osteoclast activity is more active. BrdU positive cells are able to survive throughout the entire experimental period of 30 days.
通过牙周膜牵张成骨建立正畸快速牙齿移动的动物模型，并评估包括成骨细胞、破骨细胞和骨细胞在内的细胞增殖情况。
将40只大鼠随机分为实验组和正畸对照组，在牵张开始时腹腔内注射BrdU。对照组建立传统正畸模型。实验组在上颌右侧第二磨牙近中牙槽骨部分磨除后，在第二磨牙与中切牙之间安装自制牵张装置，牵张频率为1mm/2天，一周后进入巩固期。每组随机选取4只动物在5个时间点处死。获取标本后进行免疫组化检查。然后在再生组织标本中观察BrdU标记的细胞，对阳性细胞进行计数，并使用SPSS 16.0软件包进行配对样本t检验分析。
在张力侧和压力侧均发现BrdU阳性细胞，主要为骨细胞、成骨细胞、破骨细胞和成纤维细胞。BrdU阳性成纤维细胞和成骨细胞在第10天达到峰值，实验组第5天和第10天的表达高于正畸治疗组。破骨细胞在第20天达到峰值，但正畸治疗组在第5天达到峰值。阳性骨细胞数量随时间逐渐增加，但正畸治疗组在第20天和第30天的表达低于实验组。
膜内成骨是牙周膜牵张成骨过程中的主要模式；在巩固早期和中期发生活跃的骨重塑，新骨形成持续进行，破骨细胞活性更活跃。BrdU阳性细胞能够在整个30天的实验期内存活。
