二甲基砷暴露大鼠尿中多形态砷检测分析

Determination and evaluation of arsenic speciation in urine of rat exposed to dimethyl arsenic

目的观察饮用含不同浓度二甲基砷（DMA）水大鼠尿中砷化物的代谢情况。方法初断乳健康Wistar大鼠36只，雌鼠体质量（60±5）g，雄鼠体质量（50±5）g，按体质量将大鼠随机分为对照组、低剂量组、高剂量组，每组12只大鼠（雌雄各半）。低剂量组和高剂量组大鼠分别饮用含100、200mg／LDMA的水，对照组大鼠饮用蒸馏水。染毒10周后，采用氢化物发生原子吸收分光光度法测定大鼠尿中无机砷（iAs）、一甲基砷（MMA）、二甲基砷（DMA）和三甲基砷（TMA）。结果染毒10周后，对照组，低剂量组，高剂量组大鼠尿中iAs、MMA、DMA、TMA含量中位数比较差异有统计学意义（X。值分别为25．441、25．942、25．751、17．767，P均〈0．01）。其中低剂量组大鼠尿中iAs、MMA、DMA含量中位数（2．541、4．383、24．447mg／L）均高于对照组（0．784、0．000、0．743mg／L，P均〈0．05]，高剂量组大鼠尿中iAs、MMA、DMA、TMA含量中位数（3．978、7．186、35．112、4．518mg／L）均高于对照组（0．784、0．000、0．743、0．000mg／L，P均〈0．05），且随染毒剂量的增加而升高（P〈0．05）。结论大鼠暴露DMA，大部分以原型从尿中排出，小部分可代谢转化为TMA。

Objective To observe the distribution and metabolism of arsenic speciation in urine of rats exposed to different concentrations of dimethylaraenic acid （DMA） through drinking water. Methods Thrity six weaning Wistar rats were randomly divided into normal control, low-dose group and high-dose group, 12 rats in each group（6 female and 6 male）; average body weight of female rats was （60 ± 5）g, and male rats was （50 ＋ 5）g. All rats of the 3 groups were given DMA at concentrations of 0, 100, 200 mg/L, respectively, corresponding to their specific groups through drinking water for 10 weeks. Inorganic arsenic （iAs）, monomethylarsenic acid （MMA）, DMA and trimethylarsenic compound（TMA） in urine were measured by hydride generation trapping and ultra- hypothermia coupled with atomic absorption spectrometry. Results After feeding for 10 weeks, the differences of rat urinary concentrations of iAs, MMA, DMA and TMA between normal control, low-dose group and high-dose group were statistically significant（x^2 = 25.441, 25.942, 25.751, 17.767, all P〈 0.01）. Urinary concentrations of iAs, MMA and DMA（2.541, 4.383, 24.447 mg/L） of low-dose group were significant higher than those of normal control （0.784, 0.000, 0.743 mg/L, all P 〈 0.05） ; iAs, MMA, DMA and TMA（3.978, 7.186, 35.112, 4.518 mg/L） of high-dose group were significantly higher than those of normal control （0.784, 0.000, 0.743, 0.000 mg/L, all P 〈 0.05）. The concentrations increased along with increasing doses of DMA concentrations in drinking water（all P 〈 0.05）. Conclusions After rats are exposed to DMA, most of the DMA are excreted in unchanged form in urine and a small portion of DMA is metabolized into TMA.