Effects of antioxidants on DNA-double strand breaks in human gingival fibroblasts exposed to methacrylate based monomers.

Objective: (Co)monomers from dental resin composites have cytotoxic and genotoxic potential. In previous studies it has been demonstrated that antioxidants can decrease the cytotoxicity of various dental (co)monomers. In this study the effects of the antioxidants N-acetylcysteine (ACC) and ascorbic acid (Asc) on the number of DNA double-strand breaks (DSBs) in human gingiva fibroblasts (HGFs) were tested.

Methods: HGF was incubated with the (co)monomers bisphenol-A-glycidyl methacrylate (BisGMA), urethandimethacrylate (UDMA), ethylene glycol dimethacrylate (EGDMA) or 1,3-glyceroldimethacrylate (GDMA) with and without addition of antioxidants ACC and Asc. DNA-DSBs were determined using the γ-H2AX assay.

Results: Asc induced at 500μM significant more DNA-DSBs in HGFs compared with controls (4.92 (1.28) vs. 1.62 (0.67); foci/cell mean (standard deviation), n=3). Most DNA-DSBs were found after incubation of HGFs with 90μM BisGMA (4.05 (0.56)) and 2720μM EGDMA (5.36 (1.59)). The addition of 100μM Asc or 500μM ACC leaded to a statistical significant reduction of DNA-DSBs in HGFs for all tested (co)monomers. After incubation of HGFs with 2720μM EGDMA and 500μM ACC the foci/cell decrease from 5.36 (1.59) to 1.9 (1.17) (controls: 1.12 (0.24)). After incubation of HGFs with 90μM BisGMA and 100μM Asc the foci/cell decrease from 4.05 (0.56) to 1.96 (0.59) (controls: 1.12 (0.24)).

Significance: All tested (co)monomers can induce DNA-DSBs but addition of antioxidants (Asc or ACC) leads to reduction of DNA-DSBs.