Abstract: Objective This aimed to investigate the effect of specific sequence oligodeoxynucleotide MT01 on the biological properties of osteoblasts invaded by Porphyromonas gingivalis (P. gingivalis ) by evaluating proliferation, cell cycle, and apoptosis. Methods MG63 osteoblasts were recovered and incubated with MT01, CpG ODN, metronidazole (MNZ), and gentamicin (GEN) for 3 h. P. gingivalis (the multiplicity of infection was 100∶1) was added subsequently and cocultured for another 24 and 48 h. Cells with PBS comprised the blank group, whereas cells with P. gingivalis comprised the negative controls. Six experimental groups were established: PBS group, P. gingivalis group, MT01+P. gingivalis group, CpG ODN+ P. gingivalis group, MNZ+P. gingivalis group, and GEN+P. gingivalis group. The proliferative ability was measured by methyl thiazolyl tetrazolium assay, and the percentages of apoptosis and cell cycle were examined by flow cytometry. Results Compared with the blank group, proliferation increased significantly in the MT01+P. gingivalis group (P<0.05). The ratio of cells was lower at the G₁ phase and higher at the S phase in the MT01+P. gingivalis group compared with the results in the P. gingivalis group (P<0.05). Early cell apoptosis in the MT01+P. gingivalis group was significantly lower than that in the P. gingivalis group (P<0.05). Conclusion MT01 can promote the proliferation, reduce the ratio of the G₁ phase, increase the ratio of the S phase, and inhibit the early apoptosis of osteoblasts invaded by P. gingivalis.

Key words: specific sequence oligodeoxynucleotide MT01, Porphyromonas gingivalis, osteoblast, cell cycle, apoptosis