da Silva Diana Dias, Silva Elisabete, Carvalho Félix, Carmo Helena
Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal; Institute for the Environment, Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom; REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal.
J Appl Toxicol. 2014 Jun;34(6):618-27. doi: 10.1002/jat.2885. Epub 2013 May 14.
Hepatic injury after 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) intoxications is highly unpredictable and does not seem to correlate with either dosage or frequency of use. The mechanisms involved include the drug metabolic bioactivation and the hyperthermic state of the liver triggered by its thermogenic action and exacerbated by the environmental circumstances of abuse at hot and crowded venues. We became interested in understanding the interaction between ecstasy and its metabolites generated in vivo as users are always exposed to mixtures of parent drug and metabolites. With this purpose, Hep G2 cells were incubated with MDMA and its main human metabolites methylenedioxyamphetamine (MDA), α-methyldopamine (α-MeDA) and N-methyl-α-methyldopamine (N-Me-α-MeDA), individually and in mixture (drugs combined in proportion to their individual EC01 ), at normal (37 °C) and hyperthermic (40.5 °C) conditions. After 48 h, viability was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Extensive concentration-response analysis was performed with single drugs and the parameters of the individual non-linear logit fits were used to predict joint effects using the well-founded models of concentration addition (CA) and independent action (IA). Experimental testing revealed that mixture effects on cell viability conformed to CA, for both temperature settings. Additionally, substantial combination effects were attained even when each substance was present at concentrations that individually produced unnoticeable effects. Hyperthermic incubations dramatically increased the toxicity of the tested drug and metabolites, both individually and combined. These outcomes suggest that MDMA metabolism has hazard implications to liver cells even when metabolites are found in low concentrations, as they contribute additively to the overall toxic effect of MDMA.
3,4-亚甲基二氧甲基苯丙胺（摇头丸）中毒后的肝损伤具有高度不可预测性，似乎与用药剂量或使用频率均无关联。其涉及的机制包括药物代谢生物活化以及由其产热作用引发的肝脏高温状态，而在炎热拥挤场所滥用药物的环境状况会使这种状态加剧。我们开始关注了解摇头丸与其体内生成的代谢物之间的相互作用，因为使用者总是接触到母体药物和代谢物的混合物。为此，将人肝癌细胞株Hep G2细胞分别与摇头丸及其主要人体代谢物亚甲基二氧苯丙胺（MDA）、α-甲基多巴胺（α-MeDA）和N-甲基-α-甲基多巴胺（N-Me-α-MeDA）进行孵育，并在正常（37℃）和高温（40.5℃）条件下将它们混合（药物按各自的EC01比例混合）。48小时后，通过3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐（MTT）法评估细胞活力。对单一药物进行了广泛的浓度-反应分析，并使用浓度相加（CA）和独立作用（IA）的成熟模型，根据各个非线性logit拟合的参数来预测联合效应。实验测试表明，在两种温度设置下，混合物对细胞活力的影响均符合浓度相加模型。此外，即使每种物质的浓度单独作用时产生的影响不明显，但混合后仍会产生显著的联合效应。高温孵育显著增加了所测试药物和代谢物的毒性，无论是单独作用还是联合作用。这些结果表明，即使代谢物浓度较低，摇头丸代谢对肝细胞也具有危害影响，因为它们会对摇头丸的整体毒性作用产生累加效应。
