雷尼酸锶对大鼠上颌快速扩弓影响的实验研究

目的 探讨雷尼酸锶对大鼠上颌快速扩弓的影响。方法 36只6周龄雄性Wistar大鼠，随机分为3组，空白对照（A）组﹑扩弓（B）组﹑扩弓并给药雷尼酸锶（C）组，每组12只。A组不扩弓，也不给药雷尼酸锶；B﹑C组用双眼圈簧扩弓器扩弓，力值1 N；C组扩弓开始即每天定时给药雷尼酸锶（600 mg•kg-1）。实验第4﹑7﹑10天分批处死大鼠，测量上颌宽度，并对大鼠腭中缝进行组织学观察和成骨细胞计数。结果 扩弓结束后，A组大鼠上颌宽度无明显变化（P>0.05），B﹑C组上颌宽度较扩弓前均增加（P<0.05），而B﹑C两组间的上颌宽度无明显差异（P>0.05）。组织学观察，A组腭中缝见少量红染的纤维组织，可见间充质样细胞、软骨细胞及成骨细胞。B﹑C组腭中缝处见较多红染的纤维组织，成纤维细胞﹑软骨细胞增多，腭中缝近骨边缘处多见成骨细胞；C组成骨细胞计数多于B组。结论 上颌快速扩弓可开大发育期大鼠腭中缝，增加上牙弓及上颌宽度；雷尼酸锶可以促进大鼠上颌快速扩弓时腭中缝处成骨细胞分化，加速新骨形成及骨质沉积钙化，减少复发。

Effects of strontium ranelate on the rats’ palatal suture after rapid maxillary expansion

Objective This study investigated the effects of strontium ranelate (SrR) on the rats’ palatal suture after rapid maxillary expansion (RME). Methods Thirty-six male 6-week-old Wistar rats were randomly divided into three groups: control group (A), expansion only group (B), and expansion plus SrR group (C). Each group comprised 12 rats. Neither expansion nor SrR was given to group A. Each rat in groups B and C was set an orthodontic appliance with an initial expansive force of 1 N. The rats in group C were administered with SrR (600 mg•kg−1 body weight) at the same time every day after RME. All the rats were then euthanized in batches on days 4, 7, and 10. The width of the rats’ upper jaw was measured. Histological observation was used to section the rats and count the osteoblasts. Results After the RME, no statistical difference was observed on the rats’ upper jaw width in group A (P>0.05). However, the change of upper jaw width in groups B and C presented a statistical significance (P<0.05). By contrast, no statistical difference was observed between groups B and C (P>0.05). The rats’sections were placed under a microscope, and some red fibrous tissues, mesenchymal cells, chondrocytes, and osteoblasts were observed in group A. More red fibrous tissues, mesenchymal cells, and chondrocytes were observed in groups B and C. In addition, more osteoblasts were observed on the edge of mid-palatal suture of the rats. Group C contains more osteoblasts than group B. Conclusion RME can expand the mid-palatal suture of rats, which were in the growth development period, and increase the width of dental arch. SrR may promote osteoblast differentiation and hasten new bone formation in the expanded mid-palatal suture. Both conditions accelerate new bone formation and bone deposition calcification, which may be therapeutically beneficial to prevent relapse after RME.