代谢
食用了被海洋生物毒素软海绵酸(OA)污染的海鲜可能导致腹泻性贝类中毒,症状包括恶心、呕吐和腹痛。大鼠和人类的肝脏细胞色素P450单加氧酶(CYP)都能代谢OA。然而,代谢后的OA对肝细胞的毒性尚不清楚。我们研究的目的是检测在加入大鼠和人类重组CYP酶的情况下,HepG2细胞暴露于OA时的细胞效应,以研究物种差异。结果应与CYP特异性代谢物模式相关联。通过使用LC-MS/MS技术,建立了在大鼠和人类重组CYP酶中孵育后OA的比较代谢物轮廓。结果表明,OA代谢为氧化代谢物与解毒作用相关,主要由人类CYP3A4和CYP3A5催化。与人类CYP3A酶相比,大鼠Cyp3a1的解毒作用较低,而Cyp3a2对OA的激活作用观察到,与OA的整体转化能力较弱相一致。相比之下,人类和大鼠CYP1A2似乎将OA激活为细胞毒性中间体。总之,肝脏中可能发生不同的OA代谢机制。在低剂量的OA情况下,人类肝脏可能很好地抵御细胞毒性OA,但对于大量食用贝类的消费者,不能排除潜在风险。
The ingestion of seafood contaminated with the marine biotoxin okadaic acid (OA) can lead to diarrhetic shellfish poisoning with symptoms like nausea, vomiting and abdominal cramps. Both rat and the human hepatic cytochrome P450 monooxygenases (CYP) metabolize OA. However, liver cell toxicity of metabolized OA is mainly unclear. The aim of our study was to detect the cellular effects in HepG2 cells exposed to OA in the presence of recombinant CYP enzymes of both rat and human for the investigation of species differences. The results should be set in correlation with a CYP-specific metabolite pattern. Comparative metabolite profiles of OA after incubation in rat and human recombinant CYP enzymes were established by using LC-MS/MS technique. Results demonstrated that metabolism of OA to oxygenated metabolites correlates with detoxification which was mainly catalyzed by human CYP3A4 and CYP3A5. Detoxification by rat Cyp3a1 was lower compared to human CYP3A enzymes and activation of OA by Cyp3a2 was observed, coincident with minor overall conversion capacity of OA. By contrast human and rat CYP1A2 seem to activate OA into cytotoxic intermediates. In conclusion, different mechanisms of OA metabolism may occur in the liver. At low OA doses, the human liver is likely well protected against cytotoxic OA, but for high shellfish consumers a potential risk cannot be excluded.
来源:Hazardous Substances Data Bank (HSDB)