Objective·To investigate an optimal severe periodontitis mouse model by comparing two induction methods:simple ligature and ligature combined with injection of Porphyromonas gingivalis lipopolysaccharide(P.g.LPS).Methods·Fifteen C57BL/6 mice were divided into three groups:a healthy control group,a simple ligature-induced periodontitis group,and a ligature combined with P.g.LPS injection-induced periodontitis group.After 14 d,the following evaluations were conducted:tooth mobility and probing depth under a stereomicroscope;alveolar bone resorption[bone volume fraction,bone mineral density,the distance from the cemento-enamel junction(CEJ)to the alveolar bone crest(ABC),and the area between CEJ and ABC]analyzed via micro computed tomography(Micro-CT)and stereomicroscopic examination.The serum levels of inflammatory cytokines interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)were assessed by enzyme-linked immunosorbent assay(ELISA).Results·Compared with the simple ligature group,mice in the ligature with P.g.LPS injection group exhibited significantly increased tooth mobility[(2.20±0.45)vs(1.40±0.55)]and probing depth[(1.05±0.21)mm vs(0.58±0.39)mm],with statistically significant differences(P＜0.05).The ligature with P.g.LPS injection group also demonstrated significantly reduced bone volume fraction[(16.44%±3.35%)vs(28.97%±7.90%)]and bone mineral density[(0.42±0.04)g/cm3 vs(0.55±0.08)g/cm3],as well as increased distance from CEJ to ABC[(0.88±0.03)mm vs(0.74±0.12)mm]and area between CEJ and ABC[(0.34±0.01)mm2 vs(0.30±0.02)mm2],all with statistically significant differences(all P＜0.05).Additionally,serum levels of TNF-α and IL-1β were significantly elevated in the ligature with P.g.LPS injection group compared to the simple ligature group(both P＜0.05).Conclusion·The method of ligature combined with continuous P.g.LPS injection is more effective for constructing a severe periodontitis mouse model,making it suitable for studying the progression and treatment of severe periodontitis.

Objective·To investigate an optimal severe periodontitis mouse model by comparing two induction methods:simple ligature and ligature combined with injection of Porphyromonas gingivalis lipopolysaccharide(P.g.LPS).Methods·Fifteen C57BL/6 mice were divided into three groups:a healthy control group,a simple ligature-induced periodontitis group,and a ligature combined with P.g.LPS injection-induced periodontitis group.After 14 d,the following evaluations were conducted:tooth mobility and probing depth under a stereomicroscope;alveolar bone resorption[bone volume fraction,bone mineral density,the distance from the cemento-enamel junction(CEJ)to the alveolar bone crest(ABC),and the area between CEJ and ABC]analyzed via micro computed tomography(Micro-CT)and stereomicroscopic examination.The serum levels of inflammatory cytokines interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)were assessed by enzyme-linked immunosorbent assay(ELISA).Results·Compared with the simple ligature group,mice in the ligature with P.g.LPS injection group exhibited significantly increased tooth mobility[(2.20±0.45)vs(1.40±0.55)]and probing depth[(1.05±0.21)mm vs(0.58±0.39)mm],with statistically significant differences(P＜0.05).The ligature with P.g.LPS injection group also demonstrated significantly reduced bone volume fraction[(16.44%±3.35%)vs(28.97%±7.90%)]and bone mineral density[(0.42±0.04)g/cm3 vs(0.55±0.08)g/cm3],as well as increased distance from CEJ to ABC[(0.88±0.03)mm vs(0.74±0.12)mm]and area between CEJ and ABC[(0.34±0.01)mm2 vs(0.30±0.02)mm2],all with statistically significant differences(all P＜0.05).Additionally,serum levels of TNF-α and IL-1β were significantly elevated in the ligature with P.g.LPS injection group compared to the simple ligature group(both P＜0.05).Conclusion·The method of ligature combined with continuous P.g.LPS injection is more effective for constructing a severe periodontitis mouse model,making it suitable for studying the progression and treatment of severe periodontitis.