Additive effects of TEGDMA and hydrogenperoxide on the cellular glutathione content of human gingival fibroblasts

ObjectivesOnly few data are available about cytotoxic effects of leachable dental resin compounds in combination with hydrogen peroxide (H2O2) segregated from dental bleaching agents. Therefore, the purpose of this study was to evaluate the effects of various concentrations of triethylene-glycol dimethacrylate (TEGDMA) and H2O2 on intracellular glutathione levels (GSH) and viability of human gingival fibroblasts (HGF) that are primary target cells of cytotoxic actions of these substances.MethodsHGF were grown in 96-well plates for 24 h, treated with various concentrations of TEGDMA (0.5–5.0 mM) for 24 h and subsequently for 90 min with 0.2 mM H2O2 or culture medium (control). The relative intracellular GSH concentration was determined using a fluorescence assay with monobromobimane. Readings were normalized to cell numbers, which were determined by a propidium iodide assay. Data were statistically analyzed by t-test and ANOVA with Tukey's post test. A significance level of p < 0.05 was used.ResultsExposure to TEGDMA reduced the viability of HGF at concentrations ≥1.0 mM. TEGDMA induced a decrease of the GSH pool in a concentration-dependent manner (p < 0.05). The depletion of GSH was correlated with a reduction of viability (p < 0.05) and the total cell number. Furthermore, a significant decrease of the intracellular GSH content was found when cells were exposed to TEGDMA in combination with H2O2, compared to experiments without H2O2.SignificanceWe conclude from our findings that TEGDMA and H2O2 have additive adverse effects on GSH metabolism and cell viability.