中文摘要：

目的观察小鼠腭中缝在机械扩张力作用的不同阶段成骨与破骨现象,探讨两种现象在腭中缝机械力扩张骨改建过程中的意义。方法选用6周龄健康雄性C57BL/6小鼠90只,随机分成对照1d、3d、7d、14d、28d组和实验加力1d、3d、7d、14d、28d组,每组各9只。用两眼簧扩弓器施加扩张力（0.56N）于实验加力组小鼠的腭中缝。于加力后1d、3d、7d、14d、28d通过苏木素-伊红染色观察腭中缝组织形态学的改变,碱性磷酸酶染色（ALP）和抗酒石酸酸性磷酸酶染色（TRAP）观察腭中缝组织中成骨细胞与破骨细胞的变化。结果实验组1d紧邻腭骨的骨膜细胞ALP染色呈强阳性,7d实验组腭中缝明显被扩宽,缝边缘ALP染色呈强阳性。TRAP染色显示实验组第1天有破骨细胞活动而3d破骨细胞消失,7d实验组破骨细胞主要分布于鼻底侧且较第1天组多,14d实验组与7d相似而28d破骨细胞消失。结论对腭中缝施加扩张力能够促使成骨细胞与破骨细胞活化增殖,二者时间与空间的数量和分布差异导致了腭中缝扩张骨改建。

英文摘要：

Objective To detect the osteoblast and osteoclast in the maxilla palatal suture of mice during the mechanical force-expansion period and discuss the significance of them in the suture remodeling after the expansion. Methods Six-week-old male C57BL/6 mice were subjected to palatal suture expansion by opening loops with an initial force of 0.56 N for the periods of 1,3,5,7,14 or 28 days. The sequence of histological changes in the midpalatal suture bone formation of animals was detected by hematoxylin eosin staining. Osteoblasts were tested by alkaline phosphatase （ALP） staining and osteoclasts were tested by tartrate-resistant acid phosphatase （TRAP） staining. Results Starting at day 1, cells expressing alkaline phosphatase was seen. New cartilage and bone fomation were observed at the oral edges of the palatal bones at day 7; compared with the control group, osteoclasts increased significandy along the inner latcral side of the cartilaginous tissue in expansion group at day 1, day 7 and day 14 but at day 3 and day 28, they disappeared. Conclusions These findings demonstrate that expansion forces across the midpalatal suture promote bone resorption through activation of osteoclasts and bone formation and bone rebuild via increased proliferation and differentiation of periosteal cells.