纳米二氧化钛增强五价砷对丰年虾的慢性毒性作用

Titanium Dioxide Nanoparticles Enhanced Chronic Toxic Effects of Arsenate in Artemia salina

为探究长期暴露下人工纳米材料与其他污染物的联合慢性毒性效应,考察了纳米二氧化钛(titanium dioxide nanoparticles,nano-TiO_(2))与五价砷〔arsenate,As(Ⅴ)〕单独或联合暴露对丰年虾(Artemia salina)的慢性毒性效应,观察其存活率、体长、肠道形态及超微结构变化,同时测定了丰年虾对As的累积以及As在丰年虾亚细胞组分中的分布情况.结果表明:①28 d低剂量As(Ⅴ)暴露导致丰年虾存活率降低,肠道形态及肠道超微结构损伤,且nano-TiO_(2)与As(Ⅴ)联合暴露组的毒性效应增强.②与As(Ⅴ)单独暴露组相比,nano-TiO_(2)存在条件下丰年虾在暴露前期(第7和14天)对As的摄入及排泄均增加;而暴露后期(第21和28天),nano-TiO_(2)促进丰年虾排泄As的效应减弱,导致联合暴露组中丰年虾体内As的累积显著增加(P<0.05).③与As(Ⅴ)单独暴露组相比,联合暴露组中As在生物解毒组分——热稳定蛋白(heat-stable protein,HSP)组分中的占比下降.在暴露的第14、21和28天时,联合暴露组中As在HSP组分中的占比较As(Ⅴ)单独暴露组分别显著降低了39.83%±9.54%、43.27%±5.29%和50.91%±7.60%(P均小于0.05).研究显示,nano-TiO_(2)可能会抑制丰年虾对As的解毒作用,从而导致As毒性上升.

In order to explore the chronic toxic effects of manufactured nanomaterials combined with other pollutants under long-term exposure,this study investigated the chronic toxic effects of arsenate(As(Ⅴ))and titanium dioxide nanoparticles(nano-TiO_(2))on Artemia salina(A.salina)in single or combined exposure,including changes in survival rate,body length,intestinal morphology and ultrastructure.At the same time,we determined the accumulation and subcellular distribution of As in A.salina.The results showed that:(1)Exposure to low-dose As(Ⅴ)for 28 d resulted in a decrease in survival rate of A.salina and damage to intestinal morphology and ultrastructure.In addition,when co-exposed with nano-TiO_(2),the toxic effects of As was enhanced.(2)In the early exposure period(7 and 14 d),compared with the group exposed to As(Ⅴ)alone,the uptake and excretion of As in A.salina were both increased under the co-exposure of As(Ⅴ)and nano-TiO_(2).However,in the late period of exposure(21 and 28 d),the effect of nano-TiO_(2)on the increase of As excretion of A.salina was weakened,leading to a significant increase in As accumulation of A.salina in the co-exposed groups(P<0.05).(3)The proportion of As in the HSP(heat-stable protein)fraction(biodetoxification fractions)decreased in the co-exposed groups compared to the group exposed to As(Ⅴ)alone.Also,the proportion of As in the HSP fraction of the co-exposed group was significantly reduced by 39.83%±9.54%,43.27%±5.29%,and 50.91%±7.60%at 14 d,21 d,and 28 d respectively(P<0.05),compared with the group exposed to As(Ⅴ)alone.This indicates that nano-TiO_(2)may inhibit the detoxification of As in A.salina,leading to the increase of As toxicity.