Institute of Animal Nutrition, Key Laboratory of Animal Disease-Resistance Nutrition of China Ministry of Education, Sichuan Agricultural University, Ya' an, People's Republic of China.
Biol Trace Elem Res. 2013 Oct;155(1):132-41. doi: 10.1007/s12011-013-9759-8. Epub 2013 Aug 3.
Zinc has been shown to be an inhibitor of apoptosis for many years. The present study was designed to investigate effects of three zinc chemical forms on H2O2-induced cell apoptosis in IEC-6 cells via analysis of cell vitality, LDH activity, apoptosis percentage, caspase-3 activity, and Bcl-2, Bax, and caspase-3, -8, and -9 gene expression. Cells were divided into H2O2 and zinc sources+H2O2 groups, and there are three different zinc sources [zinc oxide nanoparticle (nano-ZnO), zinc oxide (ZnO), and zinc sulfate (ZnSO4)] and three concentrations (normal = 25 μM, medium = 50 μM, and high = 100 μM) used in this article. In the present study, we found the striking cytotoxicity of H2O2 higher than 200 μM on cell vitality, LDH activity, and apoptosis percentage in the cells using five different concentrations (50, 100, 200, 400, and 800 μM) of H2O2 for 4 h. Moreover, we observed that cell vitality was increased, LDH activity and apoptotic percentage were decreased, and gene expression level of Bax and caspase-3 and -9 was markedly reduced, while gene expression level of Bcl-2 and ratio of Bcl-2/Bax were increased in normal concentration groups of nano-ZnO and ZnSO4 compared with H2O2 group, but no significant difference was observed in caspase-8 gene expression. Furthermore, medium or, more intensely, high concentrations of nano-ZnO and ZnSO4 enhanced H2O2-induced cell apoptosis. Compared with nano-ZnO and ZnSO4, ZnO showed weakest protective effect on H2O2-induced apoptosis at normal concentration and was less toxic to cells at high level. Taken together, we proposed that preventive and protective effects of zinc on H2O2-induced cell apoptosis varied in IEC-6 cells with its chemical forms and concentrations, and maybe for the first time, we suggested that nano-ZnO have a protective effect on H2O2-induced cell apoptosis in IEC-6 cells.
锌多年来一直被证明是细胞凋亡的抑制剂。本研究旨在通过分析细胞活力、LDH 活性、细胞凋亡率、caspase-3 活性以及 Bcl-2、Bax 和 caspase-3、-8 和 -9 基因表达，研究三种锌化学形式对 IEC-6 细胞中 H2O2 诱导的细胞凋亡的影响。细胞分为 H2O2 和锌源+H2O2 组，有三种不同的锌源[氧化锌纳米粒子（nano-ZnO）、氧化锌（ZnO）和硫酸锌（ZnSO4）]和三个浓度（正常=25μM，中=50μM，高=100μM）用于本文。在本研究中，我们发现，使用五种不同浓度（50、100、200、400 和 800μM）的 H2O2 孵育 4 小时后，H2O2 对细胞活力、LDH 活性和细胞凋亡率的细胞毒性明显高于 200μM。此外，我们观察到，细胞活力增加，LDH 活性和凋亡率降低，Bax 和 caspase-3 和 -9 的基因表达水平明显降低，而正常浓度组的 nano-ZnO 和 ZnSO4 的 Bcl-2 基因表达水平和 Bcl-2/Bax 比值增加与 H2O2 组相比，但 caspase-8 基因表达无明显差异。此外，中浓度或更高浓度的 nano-ZnO 和 ZnSO4 增强了 H2O2 诱导的细胞凋亡。与 nano-ZnO 和 ZnSO4 相比，ZnO 在正常浓度下对 H2O2 诱导的细胞凋亡表现出最弱的保护作用，在高浓度下对细胞的毒性也较小。综上所述，我们提出锌对 H2O2 诱导的细胞凋亡的预防和保护作用因化学形式和浓度而异，并且我们首次提出 nano-ZnO 对 IEC-6 细胞中 H2O2 诱导的细胞凋亡具有保护作用。
