Background: This study aims to evaluate the ameliorative effect of carvacrol, an anti-inflammatory monoterpenoid phenol and a major component of Plectranthus amboinicus, on periodontal damage in an experimental rat model of periodontitis.
Methods: Forty Sprague-Dawley rats were divided into ligation (Lig), non-ligation (n-Lig), and two ligation plus carvacrol (Lig+C) groups. Carvacrol (17.5 or 35.0 mg/kg body weight/day) was administered intragastrically from 1 day before ligation. On day 8, dental alveolar bone loss and gingival inflammation in periodontal specimens were examined by dental radiography, microcomputed tomography, and histology. Expressions of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, and inducible nitric oxide synthase messenger (m)RNAs, and levels of matrix metalloproteinase (MMP)-2 and MMP-9 in gingiva were examined by reverse transcription-polymerase chain reaction and zymography.
Results: Dental radiography revealed periodontal bone-supporting ratios in Lig and Lig+C groups were lower than the n-Lig group, with Lig group ratios being lowest. Compared with the n-Lig group, the cemento-enamel junction-bone distance was significantly longer in Lig and Lig+C groups, with Lig+C groups showing shorter distances regardless of radiographic methods used. Histology and histometry showed less inflammatory area and stronger connective tissue attachment in Lig+C groups than in the Lig group. Cytokine/mediator mRNA expression and MMP-9 levels were reduced in the Lig+C groups.
Conclusions: Carvacrol reduced tissue damage and bone loss caused by ligation-induced periodontitis. The present results indicate that carvacrol might reduce tissue destruction by downregulating expression of proinflammatory mediators and MMP-9.
Keywords: Cytokines; inflammation; interleukins; matrix metalloproteinases; nitric oxide synthase type II; periodontitis.