Objective Using immunohistochemistry and RT-PCR two detection methods, We aimed to investigate the changes of osteoprotegerin（OPG） and Wnt-1 expression in tension side by periodontal tissue during orthodontic tooth movement in rats and detect the relationship between OPG, Wnt-1 and orthodontic periodontal tissue remodelling. Methods Orthodontic tooth movement model of 80 merely rats was prepared, and at the 1, 3, 5, 7 d after tooth movement the teeth were extracted respectively. The hematoxylin-eosin staining of rats tension side of the morphology of periodontal tissue was observed, and the RT-PCR and immunohistochemical method was used to detect Wnt-1 and OPG expression in tension side periodontal tissue. Results The expression of OPG were weak in normal periodontal tissue. In tension area, OPG expression increased in 3 days, then reached the maximum at day 5, and new bone formation could be seen at that time; on day 7, OPG expression declined. There was no Wnt-1 expression in RT-PCR, but on day 3, 5, Wnt-1 expression positive cells of the periodontal ligament cell in immunohistochemical method. Conclusion OPG participated in the process of orthodontic periodontal tissue rebuilding, and the OPG expression increased in tension area in a time -dependent manner; the correlation of Wnt-1 with orthodontic periodontal tissue reconstruction is not certain, need to be studied further.
