Fig. 2

Nano-ZnO exposure induced cell cycle G2/M arrest in HBE cells. A. Cell cycle assay at indicated time points between HBE cells treated with or without 30 µg/ml Nano-ZnO. B. Quantification of cell cycle distribution. C. Comet assay at 4 h after 30 µg/ml Nano-ZnO treatment in HBE cells. D. For the time-response study, cells were treated with 30 μg/mL of Nano-ZnO for 2, 4, 6, 8 h. For the dose–response study, cells were treated with 25, 50, 75, and 100 μg/mL of Nano-ZnO for 24 h. Cells without treatment were used as the “0”. Nuclear protein was subjected to Western blot. ATR, p-CHK1, ATM, p-ATM and γH2AX were detected their proteins’ expression. Con Control group