食物慢性砷暴露对小鼠脑组织中砷形态的影响

为探索食物慢性砷暴露对生物体脑组织的影响,本研究以水稻中的砷形态和比例为参考,设计了三个含砷剂量组:模拟组(S):0.91 mg/kg;低剂量组(L):9.10 mg/kg;高剂量组(H):30 mg/kg,对C57BL/6小鼠进行为期三个月的染毒研究,并测定小鼠血和脑组织中总砷和各种砷形态(i AsIII、i AsV、MMA、DMA和As B)的含量。结果显示,在C、S、L和H中,血的总砷含量分别为0.022、0.023、0.068和0.132 mg/kg;大脑的总砷含量分别为0、0.006、0.075和0.172 mg/kg;其中,五种砷形态均可在血液中检测到,在L、H组小鼠大脑中仅检测到DMA和未知形态的砷(u As)。因此,小鼠血液和大脑中的总砷含量随暴露剂量增大而升高,砷在体内的解毒过程也随暴露剂量增大而加速;血液中有机砷与无机砷之比可反映机体砷暴露水平;尽管食物中无机砷不能通过血脑屏障,但由于大脑中仍能检测到低毒的DMA和毒性未知的u As,因此,食物的砷毒特别是大米的砷毒性仍应引起关注。

Arsenic Species Analyses of Mice Brain under Chronic Arsenic Exposure through Food

In order to explore the effects of chronic arsenic (As) exposure in food on organisms, in this study, As-treated feeds with the proportion of the arsenic composition in rice were prepared and three arsenic-containing dose groups (Simulate dose group: 0.91 mg/kg, Low dose group: 9.10 mg/kg, High dose group: 30 mg/kg) were designed according to the dose gradient, which were used to feed C57BL/6 mice over three months and the contents of total arsenic and five arsenic species (iAsIII, iAsV, MMA, DMA and AsB) in blood and brain tissues of mice were determined. In groups of C, S, L and H, the total arsenic (tAs) contents in blood were 0.022, 0.023, 0.068 and 0.132 mg/kg, respectively, and the total arsenic contents in brain were 0, 0.006, 0.075 and 0.172 mg/kg, respectively. While the five arsenic species can be detected both in blood, and only DMA and some unknown As species (uAs) were detected in the brain in groups of L and H. The results presented a clear dose-related accumulations of total arsenic (tAs) reflected both in blood and brain, the detoxification process of arsenic in vivo also accelerated with the increase of exposure dose, and the ratio of organic arsenic/inorganic arsenic (oAs/iAs) can reflect the dose of arsenic exposure. Thus, the current study indicated that although the toxic iAs in food could not transfer across the blood-brain barrier and the toxicity of As in food especially for the staple should be concerned.