A morphometric and histopathologic evaluation of the effects of propolis on alveolar bone loss in experimental periodontitis in rats

Background: Propolis collected by honeybees from various plant sources is a resinous hive product possessing a broad spectrum of biologic activities. Propolis has been used extensively in the diet to improve health and prevent disease. The purpose of this study was to analyze the morphometric and histopathologic changes associated with experimental periodontitis in rats in response to the systemic administration of propolis. Methods: Forty Wistar rats were divided into four experimental groups: non-ligated (NL; IN = 10); ligature only (LO; N = 10); and systemic administration of ligature and propolis (100 mg/kg body weight per day [Pro100; N = 10] or 200 mg/kg body weight per day [Pro200; N = 10]). Silk ligatures were placed at the gingival margin of the lower first molars in both mandibular quadrants. The study duration was 11 days, and the animals were sacrificed at the end of this period. Changes in alveolar bone levels were clinically measured, and tissues were histopathologically examined to assess the differences among the study groups. Results: At the end of 11 days, alveolar bone loss was significantly higher in the LO group compared to the NL, Pro 100, and Pro200 groups (P<0.05). Osteoclast numbers in the LO group were significantly higher than those of the NL, Pro 100, and Pro200 groups (P<0.05). Both dosages of propolis significantly reduced the periodontitis-related bone loss, but the differences between the two propolis groups were not statistically significant (P>0.05). Conclusion: The findings of this study provide morphologic and histologic evidence that propolis, when administered systemically, prevents alveolar bone loss in the rat model.