Piperine inhibit inflammation, alveolar bone loss and collagen fibers breakdown in a rat periodontitis model.

BACKGROUND AND OBJECTIVE: Piperine exhibits anti-inflammatory activity, and has a long history of medicinal use. The objective of this study was to investigate the protective effects of piperine on inflammation, alveolar bone and collagen fibers in experimental periodontitis. We evaluated the related expression of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, matrix metalloproteinase (MMP)-8 and MMP-13 to enhance insight into these effects. MATERIAL AND METHODS: Thirty-two Wistar rats were divided into four groups of eight animals each: control group, periodontitis group, periodontitis plus 50 mg/kg piperine group and periodontitis plus 100 mg/kg piperine group. Histopathologic changes were detected by hematoxylin and eosin staining. Alveolar bone loss and trabecula microstructures were evaluated by micro-computed tomography. Changes in collagen fibers were assessed by picrosirius red staining. Western blot analysis was conducted to determine the levels of IL-1beta, TNF-alpha, MMP-8 and MMP-13. RESULTS: Piperine clearly inhibited alveolar bone loss and reformed trabecula microstructures in a dose-dependent manner. Histological staining showed that piperine significantly reduced the infiltration of inflammation in soft tissues. Both doses of piperine limited the fractions of degraded areas in collagen fibers. Piperine (100 mg/kg) significantly downregulated the expressions of IL-1beta, MMP-8 and MMP-13 in periodontitis, but not that of TNF-alpha. CONCLUSION: Piperine displays significantly protective effects on inflammation, alveolar bone loss, bone microstructures and collagen fiber degradation in experimental periodontitis. The effects may be ascribed to its inhibitory activity on the expressions of IL-1beta, MMP-8 and MMP-13.