Mechanism of detoxification of the cationic antibacterial monomer 12-methacryloyloxydodecylpyridiniumbromide (MDPB) by N-acetyl cysteine

ObjectivesThe protective effects of N-acetyl cysteine (NAC) against cytotoxicity induced by conventional dental resin monomers have been widely documented. However, its effectiveness to detoxify cationic antibacterial monomers has not yet been elucidated. The aim of the present study was to investigate the possible protective effects of NAC against the cytotoxicity of 12-methacryloyloxydodecylpyridiniumbromide (MDPB) and explore the role of adduct formation in NAC-directed detoxification.MethodsThe influences of NAC on the cytotoxicity of MDPB were studied in mouse osteoblast-like MC3T3-E1 cells using the MTT assay. Ultra-performance liquid chromatography (UPLC) and liquid chromatography–mass spectrometry (LC–MS) analysis were performed to investigate the possible chemical reaction between NAC and MDPB.ResultsWhile only slight reduction in the cytotoxicity of MDPB by NAC was observed immediately after mixing with MDPB, remarkable protection against MDPB-induced cell death was detected when the mixture was tested after 24 h of pre-incubation. UPLC and LC–MS analysis revealed that chemical binding of MDPB and NAC occurred under neutral conditions after 24 h of pre-incubation.SignificanceOur findings suggest that NAC reduces the toxicity of the cationic antibacterial monomer MDPB, and adduct formation is partially responsible for the detoxification ability of NAC against MDPB-induced cell damage.