Objective To investigate the effect of Am80 on innate immune response of Porphyromonas gingivalis(Pg) W83-induced periodontitis in mice.Methods Twenty-five mice were randomly divided into five groups,control group,PgW83-induced periodontitis group(periodontitis),Am80 (10 μg/d) treatment group(low-dose group),Am80(50 μg/d) treatment group(middle-dose group),Am80 (100 μg/d) treatment group(high-dose group).The distance of alveolar bone resorption in each mouse was observed and measured lby a dissecting microscope.Enzyme-linked immunosorbent assay(ELISA) was used to detect the level of serum anti-Pg specific IgG.The mRNA expression of interferon-γ(IFN-γ) and interleuking-12(IL-12) in gingival tissues,draining lymph node and spleen were detected bv real-time reverse transcriptase polymerase chain reaction(RT-PCR).The measurement data were statistically analvzed.Results The resorption rate in Am80 group[(121 ± 10)％] and high-dose of Am80 group[(108±8)％] was significantly different with that in periodontitis mice[(133± 10)％](P＜0.05).The serum levels of anti-Pg specific IgG of the Am80 groups of different doses(0.437 ± 0.083,0.566 ± 0.012,and 0.386± 0.078) were significantly lower than that of the periodontitis group(l.151±0.433) (P＜0.001).Real-time quantitative PCR assay showed that after Am80 treatment,the IL-12 mRNA levels in the gingival tissues,lymph nodes and spleen of mice were reduced to 1.107±0.088,0.806±0.220,and 0.668±0.756,which were all significantly different with those in periodontitis(P＜0.01).Similarly,the relative expression of IFN-γ mRNA levels in gingival tissue,lymph nodes and spleen of mice were reduced to 8.898±0.427,16.654±5.995,and 1.482± 0.033,which were significantly different with periodontitis(P＜0.001).Conclusions Am80 can reduce the extent of inflammation and alleviate alveolar bone resorption by modulating innate immune response.