Institute of Biochemistry and Clinical Biochemistry, Catholic University, Rome, Italy.
Dent Mater. 2011 May;27(5):e87-98. doi: 10.1016/j.dental.2011.01.002. Epub 2011 Mar 2.
Methacrylic monomers are released, from dental composite resins, either into the oral cavity or in pulpal tissues, where they can cause local or systemic adverse effects. The mechanisms of these effects are not well understood, probably because such molecules can act at different levels also inducing a depletion of intracellular glutathione (GSH). GSH can detoxify methacrylates by conjugating their α,β-unsaturated carbon-carbon moiety to the thiol group, with the catalysis of glutathione S-transferases (GST). This reaction determines a GSH cellular depletion and belongs to the metabolism of α,β-unsaturated esters, protecting the body against the toxic effects of electrophiles. On the basis of the above considerations, this work aim is to set up a method for the detection of the adducts formed by methacrylic monomers with GSH in cells using HPLC coupled to mass spectrometry (HPLC-MS) and micellar electrokinetic capillary chromatography (MECK) techniques.
Adducts of glutathione with triethylene glycol dimethacrylate (TEGDMA) and hydroxyethyl methacrylate (HEMA) were incontrovertibly identified by HPLC-MS and MECK in human gingival fibroblasts and erythrocytes, both outside and inside cells. Molecular docking simulations of HEMA and TEGDMA in the experimental structure of glutathione S-transferase, are also reported to rationalize the effectiveness of such enzyme in the catalysis of the above described reaction.
The setup of a method for the identification of GSH-methacrylate adducts allows to determine when the metabolic pathway involving such compounds is employed by cells for the detoxification of monomers leached from composite resins.
甲基丙烯酸单体从牙科复合树脂中释放到口腔或牙髓组织中，可能会引起局部或全身不良反应。这些影响的机制尚不清楚，可能是因为这些分子可以在不同水平上发挥作用，也可以诱导细胞内谷胱甘肽（GSH）耗竭。GSH 可以通过将其α，β-不饱和碳-碳部分与硫醇基团共轭，来解毒甲基丙烯酸酯，这一过程由谷胱甘肽 S-转移酶（GST）催化。该反应导致 GSH 细胞耗竭，属于α，β-不饱和酯的代谢，可保护身体免受亲电物质的毒性影响。基于上述考虑，本工作旨在建立一种使用高效液相色谱-质谱联用（HPLC-MS）和胶束电动毛细管色谱（MEKC）技术检测细胞中甲基丙烯酸单体与 GSH 形成的加合物的方法。
在人牙龈成纤维细胞和红细胞中，通过 HPLC-MS 和 MEKC 无可争议地鉴定了 GSH 与三甘醇二甲基丙烯酸酯（TEGDMA）和羟乙基甲基丙烯酸酯（HEMA）形成的加合物。还报告了 HEMA 和 TEGDMA 在 GST 实验结构中的分子对接模拟，以合理化该酶在上述反应催化中的有效性。
建立一种用于鉴定 GSH-甲基丙烯酸酯加合物的方法，可以确定细胞何时采用涉及此类化合物的代谢途径来解毒从复合树脂中浸出的单体。
