Objectives: This study was aimed to investigate the distribution of matrix metalloproteinases(MMPs) on dental follicle and paradental tissues and effects of indomethacin on the MMPs by immunohistochemical method. Methods: The ten mongrel dogs, aged about 13-14 weeks, were divided into 5 groups; four experimental groups administered indomethacin 2mg/Kg/d and 8mg/Kg/d orally two times a day for 14 days and 7 days, and control group administered placebo. Permanent teeth on their way of eruption and their surrounding tissues were selected. H & E, Masson's trichrome staining and Immunohistochemical stainings by using antibodies to MMP-3, -9, and -13 were performed and examined under the light microscope. Results: 1.Many osteoclasts, osteoblasts, fibroblasts, neutrophils and newly formed capillaries were shown on the resorbing alveolar bone surface and bone marrow. 2.Indomethacin administered experimental groups showed less appearance of osteoclasts compare to control group 3.MMP-3 and -9 showed to be expressed in osteoclasts, osteoblasts, dental follicle comprising cells and endothelial cells. And also expressed in ameloblasts and odontoblasts of developing tooth. 4.MMP-13 was not expressed in dental follicle and paradental tissues but expressed in osteoblasts, osteoclasts, ameloblasts and in odontoblasts. 5.Indomethacin administered experimental groups showed reduced expression of MMP-3 and -9 in some of osteoclasts but MMP-13 showed no difference between experimental group and control group.
Conclusion: These results suggest that MMP-3, -9 and -13 play a role in bone resorption for the formation of eruption pathway in the process of tooth eruption and also participate in amelogenesis and dentinogenesis. Indomethacin inhibited MMP-3 and -9 expression in some osteoclasts, thus indicating reduced osteoclastic activity. So, when indomethacin is administered for long period, tooth eruption could be delayed.