Human and Environmental Toxicology, University of Konstanz, 78457 Konstanz, Germany.
Cawthron Institute, 7010 Nelson, New Zealand.
Toxins (Basel). 2019 Jul 2;11(7):388. doi: 10.3390/toxins11070388.
Cyanobacterial microcystins (MCs), potent serine/threonine-phosphatase inhibitors, pose an increasing threat to humans. Current detection methods are optimised for water matrices with only a few MC congeners simultaneously detected. However, as MC congeners are known to differ in their toxicity, methods are needed that simultaneously quantify the congeners present, thus allowing for summary hazard and risk assessment. Moreover, detection of MCs should be expanded to complex matrices, e.g., blood and tissue samples, to verify in situ MC concentrations, thus providing for improved exposure assessment and hazard interpretation. To achieve this, we applied two synthetic deuterated MC standards and optimised the tissue extraction protocol for the simultaneous detection of 14 MC congeners in a single ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) run. This procedure was validated using plasma and liver homogenates of mice (male and female) spiked with deuterated MC standards. For proof of concept, tissue and plasma samples from mice i.p. injected with MC-LR and MC-LF were analysed. While MC-LF was detected in all tissue samples of both sexes, detection of MC-LR was restricted to liver samples of male mice, suggesting different toxicokinetics in males, e.g., transport, conjugation or protein binding. Thus, deconjugation/-proteinisation steps should be employed to improve detection of bound MC.
蓝藻微囊藻毒素（MCs）是一种强效的丝氨酸/苏氨酸磷酸酶抑制剂，对人类健康构成的威胁日益增大。目前的检测方法针对的是仅能同时检测少数几种 MC 同系物的水体基质进行了优化。然而，由于 MC 同系物的毒性已知存在差异，因此需要开发能够同时定量存在的同系物的方法，从而能够进行综合的危害和风险评估。此外，应将 MC 的检测扩展到复杂基质，例如血液和组织样本，以验证原位 MC 浓度，从而为改善暴露评估和危害解释提供依据。为实现这一目标，我们应用了两种合成氘代 MC 标准品，并优化了组织提取方案，以便在单次超高效液相色谱-串联质谱（UPLC-MS/MS）运行中同时检测 14 种 MC 同系物。该程序通过用氘代 MC 标准品对雄性和雌性小鼠的血浆和肝匀浆进行加标来进行验证。为了验证概念，我们分析了腹腔注射 MC-LR 和 MC-LF 的小鼠的组织和血浆样本。尽管 MC-LF 存在于两性所有组织样本中，但 MC-LR 的检测仅限于雄性小鼠的肝样本，这表明 MC 在雄性动物体内的毒代动力学存在差异，例如运输、结合或蛋白质结合。因此，应采用去结合/去蛋白化步骤以提高对结合 MC 的检测。
