Fig. 1: Combined palmitic acid intake and age exacerbate the bone-destructive impact of P. gingivalis.

Young (5 weeks) and old (≥73 weeks) mice were fed either normal (ND), palmitic acid (PA) enriched diets (ED) or oleic acid (OA) ED inoculated with Porphyromonas gingivalis (P.g.) or PBS as control to induce periodontitis. a TRAP-stained mandibular bone sections of young (upper panel) and old (lower panel) P.gingivalis-infected animals after 16 weeks of dietary intervention. Sections were stained for TRAP (depicted in red) and counterstained with Meyer’s Hemalaun (blue). b Crestal bone loss was analyzed as the CEJ–ABC distance measured at the proximal bone peak between M1 and M2. c Number of TRAP⁺ osteoclasts (OC) per millimeter (mm). d Lacunae in alveolar bone adjacent to PdL. Data sets of the two age groups (young vs old) shown in (b–d) were depicted as fold change of ND/PBS within their respective age group. Data derived from 5 to 6 mice per condition (ND - normal standard diet, PA - PA-ED, OA- OA-ED; ctrl, placebo-infection; P.g. - Porphyromonas gingivalis infection). Statistical analysis: ANOVA with post hoc test (Tukey), within treatment groups, and two-tailed Student’s t test for pairwise comparisons. *p < 0.05. Scale bar in (a): 200 μm.