The potential anti-inflammatory effect of hyaluronic acid gel alone or in combination with grapefruit seed extract on induced periodontitis in mandibular molars of Wistar rats

Objectives: Antimicrobial agents have been used in conjunction with conventional chemomechanical therapy to improve the treatment outcomes of periodontitis. This study aimed to evaluate the ameliorating effect of topical application of hyaluronic acid (HA) with or without grapefruit seed extract (GFSE) (5, 10, and 15 wt. %) in induced periodontitis in rats.

Methods: Surgical alveolar bone defects were created in 30 adult male Wistar rats, followed by the introduction of a ligature impregnated with Escherichia coli lipopolysaccharide for four weeks to induce periodontitis. Rats were distributed into five groups (n = 6); an untreated periodontitis group and four treated groups in which gel (HA +/- GFSE) was injected into the sulcus once weekly for two weeks. All rats were euthanized six weeks after starting the experiment, and the mandibles were prepared for histopathological and histomorphometric analyses. Enzyme-linked immunosorbent assay was used for measuring tissue levels of tumor necrosis factor-alpha (TNF-α), transforming growth factor-β1 (TGF-β1), and paraoxonase-1 (PON-1) enzyme.

Results: HA enhanced new bone formation at defect margins, thereby diminishing defect width. This effect significantly increased as HA was combined with GFSE in a dose-dependent manner. Moreover, the HA and GFSE mixture suppressed the tissue levels of TNF-α and TGF-β1, thereby increasing PON-1.

Conclusion: The HA and GFSE mixtures exhibited synergistic therapeutic potential for the treatment of chronic periodontitis in a dose-dependent manner.