title: The cytotoxicity of methacryloxylethyl cetyl ammonium chloride, a cationic antibacterial monomer, is related to oxidative stress and the intrinsic mitochondrial apoptotic pathway.
abstract: Antibacterial monomers incorporated in dentin bonding systems may have toxic effects on the pulp. Thus, the cytotoxicity of antibacterial monomers and its underlying mechanisms must be elucidated to improve the safety of antibacterial monomer application. The influence of an antibacterial monomer, methacryloxylethyl cetyl ammonium chloride (DMAE-CB), on the vitality of L929 mouse fibroblasts was tested using MTT assay. Cell cycle progression was studied using flow cytometry. Production of intracellular reactive oxygen species (ROS) after DMAE-CB treatment was measured using 2,7-dichlorodihydrofluorescein diacetate staining and flow cytometry analysis. Loss of mitochondrial membrane potential, disturbance of Bcl-2 and Bax expression, as well as release of cytochrome C were also measured using flow cytometry analysis or Western blot to explore the possible involvement of the mitochondrial-related apoptotic pathway. DMAE-CB elicited cell death in a dose-dependent manner and more than 50% of cells were killed after treatment with 30 µM of the monomer. Both necrosis and apoptosis were observed. DMAE-CB also induced G1- and G2-phase arrest. Increased levels of intracellular ROS were observed after 1 h and this overproduction was further enhanced by 6-h treatment with the monomer. DMAE-CB may cause apoptosis by disturbing the expression of Bcl-2 and Bax, reducing the mitochondrial potential and inducing release of cytochrome C. Taken together, these findings suggest that the toxicity of the antibacterial monomer DMAE-CB is associated with ROS production, mitochondrial dysfunction, cell cycle disturbance, and cell apoptosis/necrosis.
authors: Department of Prosthodontics, School of Stomatology, Fourth Military Medical University.
authors: Sai
authors: S
authors: Ma
authors: Le-qun
authors: LQ
authors: Shan
authors: Yu-hong
authors: YH
authors: Xiao
authors: Fang
authors: F
authors: Li
authors: Li
authors: L
authors: Huang
authors: Lijuan
authors: L
authors: Shen
authors: Ji-hua
authors: JH
authors: Chen
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects; D008689:Methacrylates / Q000633:toxicity*; D051379:Mice; D008928:Mitochondria / Q000187:drug effects*; D023421:Models, Animal; D018384:Oxidative Stress / Q000187:drug effects*; D000644:Quaternary Ammonium Compounds / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D018709:Statistics, Nonparametric
chemical_list: D000900:Anti-Bacterial Agents; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D000644:Quaternary Ammonium Compounds; D017382:Reactive Oxygen Species; C540902:methacryloxylethyl cetyl dimethyl ammonium