Effects of systemic hydroxytyrosol application in experimental periodontitis of rats

This study aimed to determine the effects of systemically administered hydroxytyrosol (HT) on alveolar bone resorption and oxidative stress parameters in experimental periodontitis (EP). Thirty-two rats were divided randomly into four groups; 1) periodontally healthy + serum physiologic (PH-SP), 2) PH + hydroxytyrosol (PH-HT), 3) experimental periodontitis + SP (EP-SP), and 4) EP-HT. Following induction of EP, 10 mg/kg of systemic HT (test)/SP (control) was administered and continued for 14 days. The animals were euthanized on the 15th day, and the jaws were removed for histopathologic, histomorphometric, and immunohistochemical analyses. Enzyme-linked immunosorbent assay (ELISA) was used to analyze serum and gingival tissue malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSHPx) levels. The receptor activator of NF-kB ligand (RANKL), osteoprotegerin (OPG) levels, and RANKL/OPG ratio were analyzed via immunolabeling. Serum and tissue MDA, SOD, and GSH-Px levels did not differ between the groups. The immunohistochemical evaluation showed that RANKL levels and RANKL/OPG ratio in HT applied groups were significantly lower than SP applied groups. Within the limits of this study, daily administration of hydroxytyrosol at a dose of 10 mg/kg for 14 days could prevent alveolar bone destruction in experimental periodontitis. Besides, the antioxidant effect of HT could not be revealed.