Abstract: Objective: To investigate the effects and regulatory mechanism on the cell cycle of MG63 cells after infected with P. gingivalis in vitro. Methods: The cell proliferation activity and cell cycle distribution of MG63 cells were determined after infected with P. gingivalis ATCC 33277. The protein and mRNA of Cyclin D and Cyclin E were determined with real-time quantitative RT-PCR and Western immunoblot in MG63 cells after infected with P. gingivalis ATCC 33277. Results: The proliferation rate and the proportion of G1 phase in MG63 cells infected with P. gingivalis were significantly different from those of the control at 24h and 48h. The mRNA and protein expression levels of Cyclin D and E in the infected cells significantly decreased at 24 and 48h. Conclusion: MG63 cells infected with P. gingivalis reduce cell proliferation and arrest in G1 phase with low expression of mRNA and protein of Cyclin D and Cyclin E.

Key words: Periodontitis, Porphyromonas gingivalis, Cell cycle