[Effects of ZnO nanoparticles on proliferation and apoptosis of human lung epithelial BEAS-2B cells].

To investigate the effects of ZnO nanoparticles (ZnO NPs) on proliferation and apoptosis of human lung epithelial cells BEAS-2B and its molecular mechanisms.BEAS-2B cells were treated with ZnO NPs at concentrations of 3, 6 and 12 μg/ml for 12 h and 24 h, the control group was not treated with ZnO NPs, each with 3 replicate wells. Cell viability was detected by CCK-8 method, and the half lethal concentration (IC50) was analyzed. Then, the BEAS-2B cells were treated with ZnO NPs at selected concentrations of 3 and 6 μg/ml for 24 h respectively,each group was set with 3 replicate. Cell morphology was observed under inverted microscope. The morphology of cell nuclei was observed by Hochest33342 staining. The morphology of apoptosis was observed by AO staining and scanning electron microscopy. Cell cycle progression, cell apoptosis rate and the level of reactive oxygen species(ROS)were detected by flow cytometry. Western blot was used to detect the expression levels of Bcl-2 and Bax protein.Compared with the control group, the cell viability of cells treated with ZnO NPs were decreased significantly(P＜0.01), and the IC50 was 6.13 μg/ml at 24 h of drug treatment. After the cells were treated with ZnO NPs for 24 h, the levels of ROS were increased significantly(P＜0.05, P＜0.01)in 3 μg/ml, 6 μg/ml groups. The cell cycle was arrested at G2/M phase, chromatin condensation and apoptotic bodies were induced, apoptosis rate was increased significantly(P＜0.01) in 6 μg/ml group. The expression of Bcl-2 was decreased(P＜0.05), and the expression of Bax was increased (P＜0.05) in cells treated with 6 μg/ml ZnO NPs for 24 h.ZnO NPs induced ROS accumulation, blocked progress of cell cycle and induced cell apoptosis in BEAS-2B cells.目的: 探讨纳米ZnO对人肺上皮细胞BEAS-2B细胞增殖、凋亡的影响及分子机制。方法: 用终浓度为3、6、12 μg/ml的纳米ZnO处理BEAS-2B细胞12 h和24 h,对照组未加入纳米ZnO,各设3复孔,CCK-8法检测细胞活力,分析半致死浓度。筛选3、6 μg/ml纳米ZnO处理BEAS-2B细胞24 h,各设3复孔,倒置显微镜观察细胞形态,Hochest33342 染色观察细胞核,AO染色及扫描电镜观察细胞凋亡形态,流式细胞术检测活性氧水平、细胞周期进程、细胞凋亡;Western blot检测Bcl-2、Bax蛋白表达水平。结果: 与对照组相比,纳米ZnO处理组细胞活力显著下降(P＜0.01),处理24 h时IC50为6.13 μg/ml;纳米ZnO处理细胞24 h后,3 μg/ml和6 μg/ml组的活性氧水平显著升高(P＜0.05,P＜0.01)。6 μg/ml处理组细胞周期阻滞于G2/M期、染色质固缩凝集、出现凋亡小体、细胞凋亡率显著增加(P＜0.01)、Bcl-2蛋白表达显著降低(P＜0.05)、Bax蛋白表达显著升高(P＜0.05)。结论: 纳米ZnO诱导BEAS-2B细胞活性氧积累,阻滞细胞周期进程,促进细胞凋亡。.