Effect of chloride concentration on the cytotoxicity, bioavailability, and bioreactivity of copper and silver in the rainbow trout gut cell line, RTgutGC
Effect of chloride concentration on the cytotoxicity, bioavailability, and bioreactivity of copper and silver in the rainbow trout gut cell line, RTgutGC
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DOI：
10.1007/s10646-022-02543-5
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发表时间：
2022-04-01
期刊：
影响因子：
2.7
通讯作者：
Minghetti, Matteo
中科院分区：
文献类型：
--
作者：
Ibrahim, Md;Minghetti, Matteo
氯离子（Cl-）影响鱼类体内金属的生物利用度和毒性，但其影响这些过程的机制尚不清楚。在这里，我们研究了氯对虹鳟鱼肠道细胞系（RTgutGC）中铜（Cu）和银（Ag）的细胞毒性、生物利用度（即积累）和生物反应性（即诱导金属反应基因mRNA水平）的影响。细胞暴露于不同Cl浓度（0、1、5和146 mM）的介质中的金属中。采用visualminteq软件对暴露介质中的金属形态进行分析。AgNO3和CuSO4的细胞毒性基于两个终点：代谢活性和膜完整性。细胞分别暴露于AgNO3和CuSO4的500 nM培养液中24 h，测定金属的生物利用度和生物反应性。随着暴露介质中Cl-浓度的增加，Ag形态从自由离子（Ag+）转变为中性（AgCl），再转变为带负电荷的氯络合物（AgCl2-, AgCl3-），而Cu形态在所有介质中仍以两种形式（Cu2+和CuHPO4）存在。氯化物不影响银的生物利用度，但降低金属毒性和生物反应性。暴露于Ag的细胞在低Cl-培养基（0、1和5 mM）中表达的金属硫蛋白mRNA水平明显高于高Cl-培养基（146 mM）。这表明氯络合降低了银的生物反应性和毒性。相反，Cu在高氯离子（146 mM）培养基中的生物利用度和毒性高于低氯离子（0、1和5 mM）培养基中的生物利用度和毒性，这支持了Cu摄取可能通过氯离子依赖机制发生的假设。
Chloride (Cl-) influences the bioavailability and toxicity of metals in fish, but the mechanisms by which it influences these processes is poorly understood. Here, we investigated the effect of chloride on the cytotoxicity, bioavailability (i.e., accumulation) and bioreactivity (i.e., induction of mRNA levels of metal responsive genes) of copper (Cu) and silver (Ag) in the rainbow trout gut cell line (RTgutGC). Cells were exposed to metals in media with varying Cl- concentrations (0, 1, 5 and 146 mM). Metal speciation in exposure medium was analyzed using Visual MINTEQ software. Cytotoxicity of AgNO3 and CuSO4 was measured based on two endpoints: metabolic activity and membrane integrity. Cells were exposed to 500 nM of AgNO3 and CuSO4 for 24 h in respective media to determine metal bioavailability and bioreactivity. Ag speciation changes from free ionic (Ag+) to neutral (AgCl), to negatively charged chloride complexes (AgCl2-, AgCl3-) with increasing Cl- concentration in exposure media whereas Cu speciation remains in two forms (Cu2+ and CuHPO4) across all media. Chloride does not affect Ag bioavailability but decreases metal toxicity and bioreactivity. Cells exposed to Ag expressed significantly higher metallothionein mRNA levels in low Cl- media (0, 1, and 5 mM) than in high Cl- medium (146 mM). This suggests that chloride complexation reduces silver bioreactivity and toxicity. Conversely, Cu bioavailability and toxicity were higher in the high chloride medium (146 mM) than in the low Cl- (0, 1, and 5 mM) media, supporting the hypothesis that Cu uptake may occur via a chloride dependent mechanism.