Tarhoni Mabruka H, Lister Timothy, Ray David E, Carter Wayne G
School of Biomedical Sciences, University of Nottingham, Queens Medical Centre, Nottingham, UK.
Biomarkers. 2008 Jun;13(4):343-63. doi: 10.1080/13547500801973563.
We have evaluated the potential of plasma albumin to provide a sensitive biomarker of exposure to commonly used organophosphorus pesticides in order to complement the widely used measure of acetylcholinesterase (AChE) inhibition. Rat or human plasma albumin binding by tritiated-diisopropylfluorophosphate ((3)H-DFP) was quantified by retention of albumin on glass microfibre filters. Preincubation with unlabelled pesticide in vitro or dosing of F344 rats with pesticide in vivo resulted in a reduction in subsequent albumin radiolabelling with (3)H-DFP, the decrease in which was used to quantify pesticide binding. At pesticide exposures producing approximately 30% inhibition of AChE, rat plasma albumin binding in vitro by azamethiphos (oxon), chlorfenvinphos (oxon), chlorpyrifos-oxon, diazinon-oxon and malaoxon was reduced from controls by 9+/-1%, 67+/-2%, 56+/-2%, 54+/-2% and 8+/-1%, respectively. After 1 h of incubation with 19 microM (3)H-DFP alone, the level of binding to rat or human plasma albumins reached 0.011 or 0.039 moles of DFP per mole of albumin, respectively. This level of binding could be further increased by raising the concentration of (3)H-DFP, increasing the (3)H-DFP incubation time, or by substitution of commercial albumins for native albumin. Pesticide binding to albumin was presumed covalent since it survived 24 h dialysis. After dosing rats with pirimiphos-methyl (dimethoxy) or chlorfenvinphos (oxon) (diethoxy) pesticides, the resultant albumin binding were still significant 7 days after dosing. As in vitro, dosing of rats with malathion did not result in significant albumin binding in vivo. Our results suggest albumin may be a useful additional biomonitor for moderately low-level exposures to several widely used pesticides, and that this binding differs markedly between pesticides.
我们评估了血浆白蛋白作为常用有机磷农药暴露敏感生物标志物的潜力，以补充广泛使用的乙酰胆碱酯酶（AChE）抑制检测方法。通过玻璃微纤维滤器上白蛋白的保留量来定量氚标记的二异丙基氟磷酸酯（(3)H-DFP）与大鼠或人血浆白蛋白的结合。体外与未标记农药预孵育或体内给F344大鼠施用农药会导致随后(3)H-DFP对白蛋白的放射性标记减少，其减少量用于定量农药结合。在农药暴露导致AChE抑制约30%时，体外唑磷（氧类似物）、毒虫畏（氧类似物）、毒死蜱氧类似物、二嗪磷氧类似物和马拉氧磷对大鼠血浆白蛋白的结合分别比对照降低了9±1%、67±2%、56±2%、54±2%和8±1%。单独与19 microM(3)H-DFP孵育1小时后，与大鼠或人血浆白蛋白的结合水平分别达到每摩尔白蛋白0.011或0.039摩尔DFP。通过提高(3)H-DFP的浓度、增加(3)H-DFP孵育时间或用商业白蛋白替代天然白蛋白，这种结合水平可以进一步提高。农药与白蛋白的结合被认为是共价的，因为它在24小时透析后仍能保留。给大鼠施用甲基嘧啶磷（二甲氧基）或毒虫畏（氧类似物）（二乙氧基）农药后，给药7天后产生的白蛋白结合仍然显著。与体外情况一样，给大鼠施用马拉硫磷在体内并未导致显著的白蛋白结合。我们的结果表明，白蛋白可能是一种有用的额外生物监测指标，用于监测几种广泛使用的农药的中度低水平暴露，并且这种结合在不同农药之间存在显著差异。
