Department of Orthodontics, University of Seville, Seville, Spain.
Orthod Craniofac Res. 2011 Aug;14(3):138-48. doi: 10.1111/j.1601-6343.2011.01519.x.
Alveolar corticotomy surgery is an adjunctive therapy for reducing orthodontic treatment duration. The activation pathways of bone resorption involved in the tooth movement (TM) process are directly linked to the receptor activator of the nuclear factor-kB ligand (RANKL). Whether similar molecular pathways through RANKL, are shared by the acceleratory TM process (corticotomy-induced or not), sustained acceleration would therefore be expected with transgenic overexpression of this factor. We hypothesize that maintaining transgenic overexpression of RANKL will accelerate TM under force over time rather than at the beginning of therapy only; this contrasts with the corticotomy procedure.
We transfected the pcDNA3.1(+)-mRANKL transgene in vitro into NIH3T3 cells, then evaluated by PCR, Western blot and ex vivo resorption assay. Quantification of RANKL immunofluorescence, fluorescence-based tartrate-resistant acid phosphatase+ (TRAP+) osteoclast counts and histological analyses of the bone resorption area were performed and clinically correlated after a 32-day in vivo experiment comparing corticotomy and gene therapy.
In vitro experiments resulted in increased level of RANKL protein (46%, p<0.05) and greater mineral resorption (39%, p<0.05) compared to the controls. In vivo results showed increased RANKL immunoexpression for both corticotomy (twofold) and transfection groups (threefold) after 10 days. After 32 days, a similar result was obtained for the transfected group but not for the surgery group. These data correlate with the clinical effect of decelerating TM in the surgery group.
Selective gene therapy with RANKL has been experimentally tested as an alternative method to corticotomy surgery, showing higher effectiveness than surgical methods used for acceleratory purposes in orthodontics.
牙槽皮质切开术是一种辅助治疗方法，可缩短正畸治疗时间。涉及牙齿移动（TM）过程的骨吸收激活途径与核因子-kB 配体的受体激活剂（RANKL）直接相关。TM 加速过程（皮质切开术诱导或不诱导）是否通过 RANKL 共享类似的分子途径，因此预计通过该因子的转基因过表达会导致加速 TM。我们假设，维持 RANKL 的转基因过表达将随着时间的推移加速 TM，而不仅仅是在治疗开始时；这与皮质切开术程序形成对比。
我们将 pcDNA3.1(+)-mRANKL 转基因在体外转染到 NIH3T3 细胞中，然后通过 PCR、Western blot 和体外吸收试验进行评估。进行 RANKL 免疫荧光的定量、基于荧光的抗酒石酸酸性磷酸酶+（TRAP+）破骨细胞计数以及骨吸收区域的组织学分析，并在比较皮质切开术和基因治疗的 32 天体内实验后进行临床相关性分析。
体外实验导致 RANKL 蛋白水平升高（46%，p<0.05）和矿物质吸收增加（39%，p<0.05），与对照组相比。体内结果显示，在第 10 天，皮质切开术和转染组的 RANKL 免疫表达均增加了两倍。32 天后，转染组获得了类似的结果，但手术组没有。这些数据与手术组 TM 减速的临床效果相关。
RANKL 的选择性基因治疗已作为皮质切开术的替代方法进行了实验测试，其效果高于正畸加速目的的手术方法。
