Antioxidant Effect of Eugenol in Human Periodontal Ligament Fibroblasts

Kim, Yong Ho; Park, Bong Soo

Abstract

Periodontal disease (PD) is the most common osteolytic disease of alveolar bone, oral infection seen in humans worldwide. PD is a common, chronic immunoinflammatory disease initiated by a complex subgingival bacterial and results in the inflammatory destruction of periodontal tissues, including the alveolar bone periodontal ligament, and gingivae. The effects of eugenol on periodontal ligament fibroblasts (PDLF) cell under oxidative injury have not been fully studied. Despite many studies in regard to the antioxidant effect of eugenol, the protective effect of eugenol against oxidative damage to PDLF cell, as well as the relationship between eugenol and apoptosis, has not been investigated so far. The aim of this study was to assess the protective effect of eugenol against H2O2-induced oxidative stress in PDLF cell. Cell lines were separately grown as monolayers at 5% CO2 and 37degrees C humidified atmosphere using appropriate media supplemented with 10% fetal bovine serum, 2 mM glutamine and 100 microg/mL penicillin-streptomycin. DMEM/F12 was used as the culture medium for periodontal ligament fibroblast cells. The viability of the PDLF cells which induced by the different concentrations of H2O2 (control, 50, 100, 200, 400 microM) for 24 h was detected by MTT assay. Cell viability was significantly reduced in a H2O2-concentration dose-dependent manner. The mitochondria-dependent pathway of apoptosis is regulated by Bcl-xl family, such as the anti-apoptotic protein Bcl-xl, pro-apoptotic protein Bak. With H2O2 injury, the protein level of Bak was up-regulated while the protein level of Bcl-xl was down-regulated. In group treated H2O2 and eugenol, the ratio was reduced and the expression of Bak decreased at the same time, indicating that eugenol can attenuate apoptosis through mitochondrial related pathway in PDLF cells. Therefore, although the findings of this study are limited to an in vitro interpretation, we suggest that eugenol preconditioning may have a beneficial effect in the recovery of periodontal ligament from oxidative stress.