The use of mucoadhesive oral patches containing epigallocatechin-3-gallate to treat periodontitis: an in vivo study

OBJECTIVES: The application of topical drugs such as mucoadhesive oral patches (MOPs) do not irritate the mucosa and are able to increase the permeability of drugs to oral tissue. Epigallocatechin-3-gallate (EGCG) is an active ingredient that exhibits significant antibacterial and anti-inflammatory effects. The purpose of this study was to analyze the therapeutic potential of a mucoadhesive oral patch containing EGCG (MOP-EGCG) in a model of periodontitis and investigate its effects on the expression of osteoprotegerin (OPG), receptor activator of nuclear factor-kappa Β ligand (RANKL) and receptor activator of nuclear factor-κB (RANK). METHODS: A model of periodontitis was induced in Rattus novergicus used Porphyromonas gingivalis by applying 0.03 ml of bacteria locally with 1 × 10(10) colony-forming units (CFU) seven times at 2-day intervals in the central lower incisors. Periodontitis was then treated with MOP (control), a mucoadhesive oral patch containing doxycycline (MOP-doxy) or MOP-EGCG for 1 h/day for 21 days. On days 3, 5, 7, 14 and 21 after treatment, the central lower incisor was biopsied and analyzed by immunohistochemistry for RANK/RANKL and OPG expression in the gingiva tissue. RESULTS: MOP-EGCG extract significantly reduced the expression of RANKL and increased the expression of OPG and RANK (p < 0.05) when compared to the MOP-doxy and MOP groups. CONCLUSION: MOP-EGCG extract reduced the expression of RANKL and increased the expression of OPG and RANK, thus suggesting that MOP-EGCG can inhibit the loss of alveolar bone in periodontitis.