Objectives: The aim of this study is to determine the effect of some causative agents of free radicals including tricalciumphosphate on human gingival fibroblasts.
Methods: Human gingival fibroblasts (HGFs) (ScienCellTM) stimulated by nicotine, lipopolysaccharides (LPS) of Eschericia coli, hydrogen peroxide and tricalciumphosphate were used as an in vitro model. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to detect cell viability and reactive oxygen species (ROS) generation was assessed with 2’,7’ dichlorofluorescein diacetate (DCFDA). Cell viability was determined after incubation with different concentrations of test substances and incubated for 24 hours. The ROS released from HGFs was determined at the non-toxic concentration of each agent (more than 80% viability) at 0.5, 2, 4 and 8 h.
Results: The results showed that the IC50 of hydrogen peroxide for HGFs was 200 nM, IC50 for nicotine was 0.3 mM while no toxicity was found for E. coli LPS and tricalciumphosphate up to 100 μg/ml and 1mM, respectively. Nicotine (100 μM) could stimulate the release of reactive oxygen species from HGFs after incubation for 2 h while hydrogen peroxide (100 nM) caused the release of ROS after 4 h incubation. E.coli LPS did not stimulate the production of ROS. Interestingly, tricalciumphosphate (50 μM) could stimulate the release of ROS from HGFs at 2 h.
Conclusions: Tricalciumphosphate could stimulate generation of reactive oxygen species from HGFs similar to nicotine and hydrogen peroxide. This may contribute to the onset and development of periodontal diseases.
This project is supported by the Office of the Higher Education Commission and Mahidol University under the National Research Universities Initiative