OBJECTIVEThis paper aimed to determine the mRNA expression of osteoclast-related factors interleukin-6 (IL-6), interleukin-12 (IL-12) p35, IL-12p40, matrix metalloproteinase-9 (MMP-9), nuclear factor of activated T-cells cytoplasmic 1 (NFATcl), receptor activator of nuclear factor-KB (RANK), and tumor necrosis factor-α (TNF-α) mRNA in murine macrophages infected by a periodontitis patient's own tissue nucleic acid. Another aim was to investigate the effects of a periodontitis patient's own tissue nucleic acid on the differentiation of macrophages into osteoclasts.

METHODSInflammatory periodontal tissue samples of chronic periodontitis patients were taken during periodontal flap surgery, and healthy gingival tissue samples were taken from orthodontic patients during tooth extractions. Total RNA from periodontal tissue was extracted and reversely transcribed into cDNA and then cryo-preserved until further use. First, specific sequence oligodeoxynucleotide MT0I at a concentration of 1 µg · mL⁻¹ was added in murine macrophage RAW264.7, and the cells were incubated for 3 hours. Cells with PBS (1 µg · mL⁻¹) were used as negative controls. The inflammatory periodontal tissue cDNA and healthy periodontal tissue cDNA (1 µg · mL⁻¹) was added subsequently. There were four experimental groups: healthy periodontal tissue cDNA+ RAW264.7, inflammatory periodontal tissue cDNA+RAW264.7, MT01+healthy periodontal tissue cDNA+RAW264.7, and MT01+inflammatory periodontal tissue cDNA+RAW264.7. Real-time quantitative polymerase chain reaction was used to detect the mRNA expression of osteoclast-related factors IL-6, IL-12p35, IL-12p4O, MMP-9, NFATcl, RANK, and TNF-α mRNA after 3, 6, 12, and 24-hours.

RESULTSThe mRNA levels of osteoclast-related factors NFATc1, MMP-9, TNF-a, IL-6, IL-12p40, IL-12p35, and RANK in RAW264.7 were markedly upregulated with the treatment of periodontitis patient's own tissue nucleic acid. However, the mRNA expression of osteoclast-related factors was inhibited by use of an immunosuppressant MT01.

CONCLUSIONThe periodontitis patient's own tissue nucleic acid could promote the differentiation of murine macrophage into osteoclasts.