硫化镉量子点对人胚肝细胞L-02的毒性研究

Cadmium Sulfide Quantum Dots Induce Cytotoxicity in Human Embryo Liver Cells

采用乳化液膜法自组合成硫化镉量子点(CdS quantum dots,CdS QDs),探讨CdS QDs的体外毒性作用及可能的作用机制.选用人胚肝细胞(L-02)作为细胞模型,采用不同浓度的CdS QDs(0.00、1.25、2.50、5.00、10.00、20.00、40.00μg·mL-1)对L-02细胞进行染毒.24h后,检测细胞内乳酸脱氢酶(LDH)释放量、谷胱甘肽(GSH)含量和超氧化物歧化酶(SOD)活力,并比较加入抗氧化剂N-乙酞半胱氨酸(NAC)后细胞存活率的变化,同时测定了细胞内外的镉离子浓度.结果表明,与空白对照组相比,CdS QDs单独染毒组细胞存活率显著降低(p<0.05或p<0.01);加入抗氧化剂NAC后,10.00、20.00、40.00μg·mL-1染毒组细胞存活率与单独染毒组相比显著上升(p<0.01).CdS QDs浓度为5.00μg·mL-1时,细胞内Cd2+的浓度略高于细胞外Cd2+的浓度,在其他浓度下,细胞外Cd2+的浓度均显著高于细胞内Cd2+的浓度.当作用浓度上升至10.00μg·mL-1时,人胚肝细胞内LDH含量显著增加,且随着作用剂量的升高,LDH含量逐渐增加.与空白对照组相比,40.00μg·mL-1CdS QDs染毒组SOD活力和20.00μg·mL-1CdS QDs染毒组GSH含量均显著降低(p<0.05).Cd2+易透过L-02细胞的细胞膜而进入细胞内,从而造成细胞损伤.氧化损伤可能是CdSQDs对L-02细胞毒性作用的机制之一.

Cadmium sulfide quantum dots（CdS QDs）were synthesized using emulsion liquid membrane system. The cytotoxicity and mechanism of CdS QDs to cells were studied. Human fetal liver cells（L-02）were selected as models. L-02 cells were exposed to CdS QDs with different concentrations（0.00, 1.25, 2.50, 5.00, 10.00, 20.00 and 40.00μg·mL-1） for 24h, then the content of GSH and the activity of LDH and SOD were determined; Moreover, the influence of addition of N-Acetylcysteine（NAC） on the viability of cells was compared; The concentration cadmium ion both inside and outside cells were detected. Results showed that, compared with the control group, the viability of cells exposed to CdS QDs significantly decreased（p〈0.05 or p〈0.01）. In CdS QDs-NAC joint exposure groups, the viability of cells increased significantly（p0.01）in groups of 10.00, 20.00 and 40.00μg·mL-1. The extracellular Cd2＋ concentration was higher than the intracellular Cd2＋ concentration, except the 5.00μg·mL-1 group which the intracellular Cd2＋ concentration is slightly higher than the extracellular Cd2＋ concentration. Cellular LDH increased gradually with the increase of CdS QDs concentrations. Compared with the control group, both SOD activity in 40.00μg·mL-1 group and GSH contents in 20.00μg·mL-1 group decreased significantly（p〈0.05）. Cd2＋ can permeate the cell membrane easily and then into the cells, resulting in cell damage. Oxidative damage may be the mechanism of CdS QDs cytotoxicity.