REQUIMTE (Rede de Química e Tecnologia), Toxicology Laboratory, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal,
Arch Toxicol. 2014 Feb;88(2):455-73. doi: 10.1007/s00204-013-1120-7. Epub 2013 Oct 8.
The neurotoxicity of "ecstasy" (3,4-methylenedioxymethamphetamine, MDMA) is thought to involve hepatic metabolism, though its real contribution is not completely understood. Most in vitro neurotoxicity studies concern isolated exposures of MDMA or its metabolites, at high concentrations, not considering their mixture, as expected in vivo. Therefore, our postulate is that combined deleterious effects of MDMA and its metabolites, at low micromolar concentrations that may be attained into the brain, may elicit neurotoxicity. Using human SH-SY5Y differentiated cells as dopaminergic neuronal model, we studied the neurotoxicity of MDMA and its MDMA metabolites α-methyldopamine and N-methyl-α-methyldopamine and their correspondent glutathione and N-acetylcysteine monoconjugates, under isolated exposure and as a mixture, at normothermic or hyperthermic conditions. The results showed that the mixture of MDMA and its metabolites was toxic to SH-SY5Y differentiated cells, an effect potentiated by hyperthermia and prevented by N-acetylcysteine. As a mixture, MDMA and its metabolites presented a different toxicity profile, compared to each compound alone, even at equimolar concentrations. Caspase 3 activation, increased reactive oxygen species production, and intracellular Ca(2+) raises were implicated in the toxic effect. The mixture increased intracellular glutathione levels by increasing its de novo synthesis. In conclusion, this study demonstrated, for the first time, that the mixture of MDMA and its metabolites, at low micromolar concentrations, which represents a more realistic approach of the in vivo scenario, elicited toxicity to human SH-SY5Y differentiated cells, thus constituting a new insight into the context of MDMA-related neurotoxicity.
“摇头丸”（3,4-亚甲二氧基甲基苯丙胺，MDMA）的神经毒性被认为涉及肝脏代谢，尽管其真正的贡献尚不完全清楚。大多数体外神经毒性研究涉及 MDMA 或其代谢物的单独暴露，浓度较高，而没有考虑到它们在体内的混合物。因此，我们假设 MDMA 及其代谢物在可能进入大脑的低微摩尔浓度下的联合有害作用，可能会引起神经毒性。我们使用人 SH-SY5Y 分化细胞作为多巴胺能神经元模型，研究了 MDMA 及其 MDMA 代谢物α-甲氧基多巴胺和 N-甲基-α-甲氧基多巴胺及其相应的谷胱甘肽和 N-乙酰半胱氨酸单共轭物在单独暴露和混合物形式下，在常温或高温条件下的神经毒性。结果表明，MDMA 及其代谢物的混合物对 SH-SY5Y 分化细胞有毒性，这种作用在高温条件下增强，而 N-乙酰半胱氨酸可以预防。作为混合物，MDMA 及其代谢物与单独的化合物相比，即使在等摩尔浓度下，也呈现出不同的毒性特征。半胱天冬酶 3 的激活、活性氧的产生增加和细胞内 Ca(2+)的升高被认为与毒性作用有关。混合物通过增加其从头合成来增加细胞内谷胱甘肽水平。总之，这项研究首次表明，在低微摩尔浓度下，MDMA 及其代谢物的混合物代表了更接近体内情况的更现实的方法，对人 SH-SY5Y 分化细胞产生了毒性，从而为 MDMA 相关神经毒性的背景提供了新的认识。
