Oral green and red propolis attenuate bone resorption and inflammation in experimental apical periodontitis.

OBJECTIVE

To test whether systemic green or red propolis modulates inflammation and bone resorption in rat apical periodontitis (AP).

DESIGN

Twenty-four male Wistar rats received AP induction in the first mandibular molars and were randomized to Control, Green propolis, or Red propolis (n = 8/group). Propolis (100 mg/kg in water) or vehicle was administered daily by gavage for 30 days. On day 30, periapical tissues were evaluated by micro-CT, histology (inflammatory score), and immunohistochemistry for RANKL, OPG, and TRAP-positive osteoclasts. Data were analyzed with Shapiro-Wilk, Kruskal-Wallis/Dunn, or one-way ANOVA/Tukey (α=0.05).

RESULTS

Both propolis groups showed significantly less periapical bone resorption than the control group on micro-CT analysis (p < 0.05). Histological evaluation revealed predominantly chronic inflammatory infiltrates, with significantly lower inflammation scores in the propolis-treated groups (p < 0.05). Immunohistochemical analysis demonstrated a significant reduction in RANKL expression, an increase in OPG levels, and fewer TRAP-positive multinucleated cells in both propolis groups compared to the control (p < 0.05). No significant differences were observed between green and red propolis.

CONCLUSION

Thirty days of systemic green or red propolis similarly attenuated periapical inflammation and osteoclast-mediated bone resorption in experimental AP, reflected by lower resorption volumes, reduced RANKL/TRAP, and higher OPG, indicating that propolis may serve as a host-modulatory adjunct to preserve periapical bone.