Figure 1.

Zinc ion is the key mediator of ZnONPs-induced cytotoxicity. (a) MTS analysis of A549 cells treated with ZnONPs at doses of 10, 30 and 100 μg/ml. Cell viability was detected at 12 and 24 h after ZnONPs treatment. Data are representative of three independent experiments (n=6 for each group) and values are expressed in mean±S.E.M. (b) FACS analysis of cells stained with FluoZin-3, AM. The effect of 30 μg/ml ZnONPs treatment on intracellular zinc ions concentration was analyzed 24 h after treatment. Data are representative of three independent experiments. MFI=mean fluorescence intensity. (c) A549 cells were pretreated with 1 mM DTPA or 1 μM TPEN, followed by 30 or 100 μg/ml ZnONPs treatment. MTS analysis of A549 cells was performed at 24 h after treatment. Data are representative of three independent experiments (n=6 for each group) and values are expressed in mean±S.E.M. **P<0.01. (d) A549 cells were pretreated with 0, 0.1, 0.3 and 1 mM DTPA, followed by 100 μg/ml ZnONPs treatment. MTS analysis of A549 cells was then performed at 24 h after treatment. Data are representative of three independent experiments (n=6 for each group) and values are expressed as mean±S.E.M. **P<0.01. (e) A549 cells were pretreated with vehicle or 1 mM DTPA, followed by 30 μg/ml ZnONPs treatment. FACS analysis of cells stained with FluoZin-3, AM was performed at 24 h after treatment. Data are representative of three independent experiments