IADR Abstract Archives
Effect of DBPO on Oxidative Stress- and Inflammation-Related Genes
Objectives: The initiator dibenzoyl peroxide (DBPO), commonly used in polymethyl methacrylate denture base resins, is eluted in detectable amounts into the saliva due to the insufficient polymerization reaction. Aim of this study was to investigate the effect of DBPO on the gene expression related to oxidative stress and inflammation in oral keratinocytes (OKF6/TERT2) and human gingival fibroblasts (HGF).
Methods: OKF6/TERT2 and HGF were grown in 96-well-plates (cytotoxicity) or 6-well-plates (gene expression analysis) and treated with different concentrations of DBPO (3-30 µM). Cytotoxicity was determined by the Hoechst 33342 and LDH assay. Alterations in gene expression were analyzed by quantitative qPCR.
Results: DBPO was clearly cytotoxic in OKF6/TERT2 cells in a concentration dependent manner, but not in HGF. Moreover, transcripts related to oxidative stress and inflammatory responses were found to be up-regulated in OKF6/TERT2, but not in HGF. Evidently, the transcription of NAD(P)H quinone dehydrogenase 1 (NQO1) and the inducible heme oxygenase 1 (HMOX1) were significantly up-regulated in response to oxidative stress. Genes associated with inflammatory processes like the cytokines interleukin 1 beta (IL1B), interleukin 6 (IL6), and interleukin 8 (C-X-C motif chemokine ligand 8, CXCL8) exhibited a tendency of increased transcript abundance correlated with the concentration applied.
Conclusions: Our data show on the one hand that DBPO even at low micromolar concentrations mediates cytotoxic effects in keratinocytes, and on the other hand affects the activation of important genes related to oxidative stress and inflammatory responses. Furthermore, keratinocytes as the major epidermal cell type seem to be more sensitive to exogenous substances than fibroblasts.
Methods: OKF6/TERT2 and HGF were grown in 96-well-plates (cytotoxicity) or 6-well-plates (gene expression analysis) and treated with different concentrations of DBPO (3-30 µM). Cytotoxicity was determined by the Hoechst 33342 and LDH assay. Alterations in gene expression were analyzed by quantitative qPCR.
Results: DBPO was clearly cytotoxic in OKF6/TERT2 cells in a concentration dependent manner, but not in HGF. Moreover, transcripts related to oxidative stress and inflammatory responses were found to be up-regulated in OKF6/TERT2, but not in HGF. Evidently, the transcription of NAD(P)H quinone dehydrogenase 1 (NQO1) and the inducible heme oxygenase 1 (HMOX1) were significantly up-regulated in response to oxidative stress. Genes associated with inflammatory processes like the cytokines interleukin 1 beta (IL1B), interleukin 6 (IL6), and interleukin 8 (C-X-C motif chemokine ligand 8, CXCL8) exhibited a tendency of increased transcript abundance correlated with the concentration applied.
Conclusions: Our data show on the one hand that DBPO even at low micromolar concentrations mediates cytotoxic effects in keratinocytes, and on the other hand affects the activation of important genes related to oxidative stress and inflammatory responses. Furthermore, keratinocytes as the major epidermal cell type seem to be more sensitive to exogenous substances than fibroblasts.