Abstract:

BACKGROUND: Matrix metalloproteinase 7 has abilities of degrading collagen type IV, elastin, proteoglycan and fibronectin, which has been shown to be highly associated with periodontitis in gingival tissue biopsies.
OBJECTIVE: To investigate the expression of matrix metalloproteinase 7 in the periodontium of rats under orthodontic force.
METHODS: Sixty healthy male Sprague-Dawley rats aged 8 weeks were randomly divided into orthodontic force and tooth movement groups. The animal models of orthodontic tooth movement were established. The rats were sacrificed at 0, 1, 3, 7, 14 and 21 days after tooth movement, respectively. The expression and distribution of Matrix metalloproteinase 7 in the periodontium were detected by hematoxylin-eosin staining and immunohistochemistry.
RESULTS AND CONCLUSION: Matrix metalloproteinase 7 was mainly expressed in the cytoplasm of epithelial cells and macrophages, which appeared to be yellow. Matrix metalloproteinase 7 was visible in the normal tissue, and the number of cells positive for matrix metalloproteinase 7 increased with time, which peaked on day 7 after orthodontic force and then began to decrease. The expression levels of matrix metalloproteinase 7 in the periodontium of tension and pressure sides in the periodontitis tooth movement group were significantly higher than those in the control group at 0-14 days (P < 0.05). At 3 and 7 days after orthodontic force, the expression level of matrix metalloproteinase 7 in the periodontium of tension side in both groups was significantly higher than that of the pressure side (both P < 0.05). These findings show that Matrix metalloproteinase 7, as a local regulator in the periodontium, participates in the orthodontic periodontal tissue remodeling. Orthodontic force and inflammatory stimulus can up-regulate the expression of matrix metalloproteinase 7.

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

Key words: Matrix Metalloproteinase 7, Tooth Movement, Periodontitics, Tissue Engineering