Abstract: PURPOSE: To establish animal model in mice with orally infected periodontitis with Porphyromonas gingivalis and intraperitoneal injection of P.g antigen, simulate periodontal pathogens of human periodontal disease, and analyze the expression of regulatory T cells in this model. METHODS: The extent of periodontal bone resorption was measured by entity microscope, and inflammatory cell infiltration of the periodontal tissue lesions was observed by HE staining. Flow cytometric analysis was used to detect the expression of regulatory T cells in periodontal disease during the chronic inflammation. The expression levels of TGF-β1, IL-10mRNA in periodontal tissue were detected by real-time quantitative PCR. SPSS 17.0 software package was used for statistical analysis. RESULTS: After 4 weeks, compared with the normal control group, the distance between cemento-enamel junction and the alveolar crest was significantly increased in periodontal disease group(P<0.05); Massive inflammatory cells were infiltrated and periodontal pockets deepened in periodontal tissue. The expression levels of TGF-β1 and IL-10mRNA were significantly decreased (P<0.01). The ratio and numbers of Treg cells were significantly reduced in the spleen (P<0.05). CONCLUSIONS: In experimental periodontitis, the number and the function of regulatory T cells are abnormal. It may be relevant to the reduction of immune suppression cytokines.

Key words: Periodontitis, Animal model, Bone resorption, Regulatory T cell