In-vivo assessment of the osteo-protective effects of eugenol in alveolar bone tissues

Estrogen deficiency following menopausal provokes alveolar bone loss, remodeling and inflammation. Eugenol is a phenolic compound with wide dental applications and anti-inflammatory properties. In the present study, the potential protective role of eugenol against alveolar bone deformities was investigated in an ovariectomized (OVX) rodent model. Two doses of eugenol (2.5 and 5 mg/kg/d) were administered to OVX animals for 12 weeks. In Serum, markers of bone metabolism and pro-inflammatory cytokines were estimated using ELISA. Alveolar bone morphometry was analyzed using high-resolution micro-computed tomography (CT). Bone histological analysis (H&E stain) was also performed. Alveolar bone expression of osteoclastogenesis modulating factors, such as osteoprotegerin (OPG), receptor activator of nuclear factor kappa-b ligand (RANKL) and inflammatory mediators, were measured using immunohistochemistry. Eugenol failed to correct elevated body weights and uterine atrophy in OVX rats. The significant elevation of bone metabolic markers and inflammatory cytokines in OVX animals were markedly improved by eugenol treatment, particularly the higher dose. Eugenol treatment considerably attenuated morphometric trabecular alterations of the alveolar bone and improved alveolar resorption and gingival infiltration. Alveolar bone of OVX animals showed augmented expression of RANKL, OPG and inflammatory cytokines, which were corrected by eugenol treatment. Alveolar bone loss and remodeling associated with estrogen insufficiency was ameliorated by eugenol owing to its anti-inflammatory properties, suggesting an extra dental impact for eugenol.