Bile fluorescence, heme oxygenase induction, and increased biliverdin excretion by mixtures of environmental toxicants.
Bile fluorescence, heme oxygenase induction, and increased biliverdin excretion by mixtures of environmental toxicants.
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发表时间：
2006
影响因子：
4.5
通讯作者：
P. van den Hurk
中科院分区：
文献类型：
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作者：
P. van den Hurk
胆汁荧光的测量已成为显示鱼类暴露于多环芳烃的一种流行的生物标志物。关于如何使胆汁荧光正常化，已经发表了相互矛盾的数据。为了研究将胆绿素归一化为胆绿素是否是合适的方法，我们通过实验研究了鱼类体内胆绿素排泄的相关机制。在两个不同的实验中，用苯并[a]芘与镉、氯化苯酚或冰片的混合物给斑点叉尾叉结果表明，各处理组的胆汁蛋白与胆绿素之间呈线性关系，但这种关系的斜率随着鱼类受到更多的化学胁迫而显著增加。因此，在不断增加的毒物压力下，每一种蛋白质排泄出更多的胆绿素。为了研究胆绿素排泄量的增加是否与血红素降解的增加有关，我们测量了投药鱼肝脏匀浆中的血红素加氧酶(HO)的活性。在两个实验中，HO活性与胆汁中胆绿素浓度呈显著正相关。结论：混合环境污染物可诱导HO活性，这种化学应激导致胆绿素排泄增加。对这一机制途径的阐明表明，胆汁荧光不应按胆绿素吸收来表达，而按胆汁蛋白表达将是更可靠的方法。
The measurement of bile fluorescence has become a popular biomarker to demonstrate the exposure of fish to polycyclic aromatic hydrocarbons. Conflicting data has been published on how to normalize bile fluorescence. To investigate if normalization to biliverdin is a suitable method, experiments were performed to study the mechanisms related to biliverdin excretion in fish. In two separate experiments channel catfish (Ictalurus punctatus) were dosed with mixtures of benzo[a]pyrene with cadmium, chlorinated phenols or borneol. The results showed linear relationships between bile protein and biliverdin for each treatment group, but the slope of this relationship was significantly increased when fish received more chemical stress. Thus, under increasing toxicant stress, more biliverdin was excreted per amount of protein. To investigate if the increased biliverdin excretion was related to increased heme degradation, enzymatic activity of heme oxygenase (HO) was measured in liver homogenates of the dosed fish. The fish dosed with chemical mixtures had a significantly higher HO activity than the control fish, and in both experiments a significant correlation was observed between HO activity and biliverdin concentration in the bile. It is concluded that mixtures of environmental pollutants can induce HO activity and that this chemical stress leads to increased biliverdin excretion. The elucidation of this mechanistic pathway warrants that bile fluorescence should not be expressed per biliverdin absorption, and that expression per bile protein would be a more reliable method.