Figure 4.

Pre-treatment with inactivated Porphyromonas gingivalis (Pg) prevents periodontitis-aggravated glucose intolerance in high-fat diet (HFD)-fed mice. (A) Mice were injected by 10⁶ colony-forming unit (CFU) of inactivated Pg or inactivated Fusobacterium nucleatum (Fn) or inactivated Prevotella intermedia (Pi) or a mix of all inactivated bacteria or vehicle solution. One month later, mice were colonised by Pg, Fn, Pi and/or by vehicle solution for 1 month and then randomised into seven groups: NC-Vehicles (vehicle+normal chow, black bar, n=4), HFD (vehicle+HFD, red bar, n=4), high-fat diet colonised (HFD-Co) (vehicle+HFD+colonisation, green bar, n=4), HFD-Co+I B mix (inactivated mix bacteria+colonisation+HFD, black blue bar, n=4), HFD-Co+I Pg (inactivated Pg+colonisation+HFD, purple bar, n=4), HFD-Co+I Fn (inactivated Fn+colonisation+HFD, light blue bar, n=4) and HFD-Co+I Pi (inactivated Pi+colonisation+HFD, orange bar, n=4). Intraperitoneal glucose-tolerance test (IpGTT) and glycaemic index were assessed for each group after 3 months of HFD (B–F); (G) measurement of immunoglobulin G antibodies specific to lipopolysaccharide (LPS) of Pg in blood. (H) Alveolar bone loss was explored after experimental procedures for each group. Data are mean±SEM. Significant results when: **p<0.01, ***p<0.001 and ****p<0.0001 when compared to HFD vehicles, ^§p<0.05 and ^§§§§p<0.0001 when compared to NC vehicles and ^#p<0.05 and ^####p<0.0001 when compared to HFD-Co as determined by two-way analysis of variance (ANOVA) with Bonferroni's post-test for (B), (C), (D) and (E) and one-way ANOVA followed by Tukey's post-test for (F) and (G).