School of Resource and Environmental Management, Simon Fraser University, Burnaby, British Columbia, Canada.
Environ Toxicol Chem. 2014 Aug;33(8):1885-93. doi: 10.1002/etc.2636. Epub 2014 Jun 20.
In vitro biotransformation assays are currently being explored to improve estimates of bioconcentration factors of potentially bioaccumulative organic chemicals in fish. The present study compares thin-film and solvent-delivery dosing techniques as well as single versus multiple chemical dosing for measuring biotransformation rates of selected polycyclic aromatic hydrocarbons in rainbow trout (Oncorhynchus mykiss) liver S9. The findings show that biotransformation rates of very hydrophobic substances can be accurately measured in thin-film sorbent-dosing assays from concentration-time profiles in the incubation medium but not from those in the sorbent phase because of low chemical film-to-incubation-medium mass-transfer rates at the incubation temperature of 13.5 °C required for trout liver assays. Biotransformation rates determined by thin-film dosing were greater than those determined by solvent-delivery dosing for chrysene (octanol-water partition coefficient [KOW ] =10(5.60) ) and benzo[a]pyrene (KOW =10(6.04) ), whereas there were no statistical differences in pyrene (KOW =10(5.18) ) biotransformation rates between the 2 methods. In sorbent delivery-based assays, simultaneous multiple-chemical dosing produced biotransformation rates that were not statistically different from those measured in single-chemical dosing experiments for pyrene and benzo[a]pyrene but not for chrysene. In solvent-delivery experiments, multiple-chemical dosing produced biotransformation rates that were much smaller than those in single-chemical dosing experiments for all test chemicals. While thin-film sorbent-phase and solvent delivery-based dosing methods are both suitable methods for measuring biotransformation rates of substances of intermediate hydrophobicity, thin-film sorbent-phase dosing may be more suitable for superhydrophobic chemicals.
目前正在探索体外生物转化测定法，以提高对鱼类中具有潜在生物累积性的有机化学品的生物浓缩系数的估计。本研究比较了薄膜和溶剂输送给药技术以及单次和多次化学给药，以测量虹鳟鱼（Oncorhynchus mykiss）肝 S9 中选定多环芳烃的生物转化速率。研究结果表明，在 13.5°C 的孵化温度下，由于化学薄膜到孵化介质的质量转移速率较低，非常疏水物质的生物转化速率可以从孵育介质中的浓度-时间曲线准确测量，但不能从薄膜相中测量。薄膜给药法测定的生物转化速率大于溶剂输送给药法测定的生物转化速率，对于苊（辛醇-水分配系数 [KOW] = 10(5.60)）和苯并[a]芘（KOW = 10(6.04)），而在 2 种方法之间，芘（KOW = 10(5.18)）的生物转化速率没有统计学差异。在基于吸附剂输送的测定中，同时进行多次化学给药产生的生物转化速率与单次化学给药实验中测量的生物转化速率没有统计学差异，而对于芘和苯并[a]芘则没有差异，但对于苊则没有。在溶剂输送实验中，多次化学给药产生的生物转化速率远小于单次化学给药实验中的生物转化速率，对于所有测试化学品均如此。虽然薄膜吸附剂相和基于溶剂输送的给药方法都是测量中等疏水性物质生物转化速率的合适方法，但薄膜吸附剂相给药可能更适合超疏水性化学物质。
