局部注射重组人转化生长因子对大鼠正畸牙移动的影响

Effect of local injection of rhTGF-β1 on osteoclasts during orthodontic tooth movement in rats

目的:探讨局部注射重组人转化生长因子(rhTGF-β1)对大鼠正畸牙移动速度的影响。方法:80只模型大鼠随机分为实验组和对照组,每组又按1、4、7、10和14 d再分为5个小组,每小组8只。实验组从加力的第1天开始,每2 d在大鼠加力侧上颌第一磨牙颊侧黏膜下注射rhTGF-β10.1 mL(5 ng/mL),对照组注射相同容量的PBS。加力后依实验设计时间分别处死每1小组大鼠。体视显微镜观察并采集图像,运用计算机图像分析软件测量牙移动的距离,同时应用TRAP组织化学染色观察不同时段压力侧破骨细胞数量的变化,采用SPSS 17.0软件包对数据进行统计学分析。结果:局部注射rhTGF-β1的牙移动速度较对照组快,在加力后第7天,牙移动距离差异显著(P<0.05);第10天和第14天相比,差异显著(P<0.01)。实验组压力侧破骨细胞的TRAP阳性细胞数较对照组显著增多(P<0.01)。结论:局部注射rhTGF-β1增强了大鼠正畸牙破骨细胞的活性,促进了破骨细胞的骨吸收功能,加速了正畸牙移动。

PURPOSE： To investigate the effect of exogenous TGF-β1on improving periodontal tissues remodeling during orthodontic tooth movement in rats. METHODS： Eighty male SD rats were randomly divided into 2 groups. Rats in the experimental group were injected respectively with rhTGF-β1in dosages of 0.1 mL（5 ng/mL） in the buccal submucosal area of the molar every other day, while rats in the control group received equivalent volumes of PBS. Each group（n=40）was subdivided equally into 5 subgroups. An orthodontic appliance, consisting of a 5 mm nickel titanium closed coil spring, was ligated between the maxillary left incisor and first molar of each rat to deliver an initial force of 0.49 N. Eight rats in each subgroup were sacrificed at one of the five time points（1, 4, 7, 10 and 14 days） after appliance placement.The distance of the tooth movement was measured by using stereomicroscope. Tissue sections around the first maxillary left molar were stained with tartrate-resistant acid phosphatase（TRAP） histochemistry to analyze the changes of the amount and distribution of osteoclasts on the compression side of tooth. Statistical analysis was performed using SPSS 17.0 software package. RESULTS： Molars treated with rhTGF-β1moved mesially more rapidly than the control group. The distance of tooth movement of the experimental group showed a significant increase compared with the control group at day 7（P0.05）and significant increase compared with the control group at day 10 and 14（P0.01）. The number of TRAP positive cells appearing in the periodontal ligament space on the pressure side of the alveolar bone were increased markedly in experimental group. There were statistically significant differences in the amount of osteoclasts between experimental and control groups（P 0.01）. CONCLUSIONS： Local injection of rhTGF-β1in the periodontal tissues can accelerate orthodontic tooth movement via enhancing the numbers of osteoclasts. At the histologic level, increased numbers of mononuclear osteoclasts are recruited and activated, resulting in greater amounts of alveolar bone resorption on the pressure side of the periodontal ligament.