Indiana University School of Dentistry, Indianapolis, Indiana.
Histotechnology, Indiana University School of Medicine, Indianapolis, Indiana.
Orthod Craniofac Res. 2019 Aug;22(3):177-182. doi: 10.1111/ocr.12308. Epub 2019 Mar 29.
To analyse the expression of osteoblast differentiation markers and osteoclast activity in the periodontal ligament (PDL) following 2, 4 and 7 days of orthodontic tooth movement (OTM) in an animal model.
Eighteen C57BL/6 wild-type mice.
For the OTM model, orthodontic force was applied to the maxillary right first molar using a closed-coil NiTi spring activated between the molar and incisors. The left side served as the control. Following OTM, the dissected tissues were scanned for micro-computed tomography (micro-CT) analysis and processed for histology. Histological stains included tartrate-resistant acid phosphatase (TRAP) staining for osteoclasts and immunohistochemistry for osteoblast markers alpha-smooth muscle actin (α-SMA), osteopontin (OP) and osteocalcin (OC).
Micro-CT analysis showed increasing OTM on days 2, 4 and 7 days as well as decrease in bone volume and per cent bone volume at 4 and 7 days. Statistically significant increases in osteoblast marker expression were seen in all groups when compared to the control. TRAP expression was highest at 4 and 7 days, α-SMA was highest at 2 days and OP/OC was highest at 4 days.
During OTM, proliferation of pre-osteoblasts peaks at 2 days while mineralization of the osteoid peaks at 4 days. The osteoclast response is delayed.
分析正畸牙齿移动（OTM）后 2、4 和 7 天牙周韧带（PDL）中成骨细胞分化标志物和破骨细胞活性的表达。
18 只 C57BL/6 野生型小鼠。
对于 OTM 模型，使用在磨牙和切牙之间激活的闭合线圈 NiTi 弹簧在右上第一磨牙上施加正畸力。左侧作为对照。OTM 后，对解剖组织进行微计算机断层扫描（micro-CT）分析和组织学处理。组织学染色包括抗酒石酸酸性磷酸酶（TRAP）染色用于检测破骨细胞和免疫组织化学用于检测成骨细胞标志物α-平滑肌肌动蛋白（α-SMA）、骨桥蛋白（OP）和骨钙素（OC）。
micro-CT 分析显示，在第 2、4 和 7 天的 OTM 期间，骨体积和 4 天和 7 天的骨体积百分比均减少。与对照组相比，所有组的成骨细胞标志物表达均显著增加。TRAP 表达在第 4 天和第 7 天最高，α-SMA 在第 2 天最高，OP/OC 在第 4 天最高。
在 OTM 期间，前成骨细胞的增殖在第 2 天达到峰值，而类骨质的矿化在第 4 天达到峰值。破骨细胞的反应延迟。
