Zinc oxide nanoparticles (ZnO NPs) with their wide range of consumer applications in day-to-day life received great attention to evaluate their effects in humans. This study has been attempted to elucidate the DNA damage response mechanism in a dermal model exposed to ZnO NPs through Ataxia Telangiectasia Mutated (ATM)-mediated ChK1-dependent G2/M arrest. Further, viability parameters and mechanism involved in the cell death with special reference to the consequences arising due to DNA damage were explored. Our study showed that ZnO NPs at concentrations 5 and 10 µg/ml induced significant cytotoxic effect in skin cell line. Moreover, the results confirmed generation of reactive oxygen species (ROS) induces the cell death by genotoxic insult, leading to mitochondrial membrane depolarisation and cell cycle arrest. Subsequently, ZnO NPs treatment created DNA damage as confirmed via Comet assay (increase in olive tail moment), micronucleus assay (increase in micronucleus formation), double-strand breaks (increase in ATM and Ataxia Telangiectasia and Rad3 related (ATR) expression), DNA fragmentation and cell cycle (G2/M arrest) studies. Finally, marker proteins analysis concluded the mechanistic approach by demonstrating the key marker expressions HMOX1 and HSP60 (for oxidative stress), cytochrome c, APAF1, BAX, Caspase 9, Caspase 3 and decrease in BCL2 (for activating apoptotic pathway), pATM, ATR and γH2AX (for double-strand breaks), DNA-PK (involved in DNA repair) and decrease in cell cycle regulators. In together, our data revealed the mechanism of ROS generation that triggers apoptosis and DNA damage in HaCaT cell lines exposed to ZnO NPs.

中文翻译：

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ZnO纳米粒子相关的线粒体应激诱导HaCaT细胞凋亡和G2 / M阻滞：一种机械方法。

氧化锌纳米颗粒（ZnO NPs）在日常生活中的广泛消费应用受到了人们的广泛关注，以评估其对人体的影响。已尝试尝试阐明通过共济失调毛细血管扩张突变（ATM）介导的ChK1依赖性G2 / M阻滞暴露于ZnO NP的真皮模型中的DNA损伤反应机制。此外，还探索了细胞死亡中涉及的生存力参数和机制，并特别参考了由于DNA损伤而引起的后果。我们的研究表明，浓度为5和10 µg / ml的ZnO NPs在皮肤细胞系中具有明显的细胞毒性作用。此外，该结果证实了活性氧（ROS）的产生通过遗传毒性侮辱诱导细胞死亡，从而导致线粒体膜去极化和细胞周期停滞。后来，ZnO NPs处理产生了DNA损伤，已通过彗星试验（橄榄尾矩增加），微核试验（微核形成增加），双链断裂（ATM和共济失调毛细血管扩张和Rad3相关（ATR）表达增加）证实了DNA损伤和细胞周期（G2 / M阻滞）研究。最后，标记物蛋白质分析通过证明关键标记物表达HMOX1和HSP60（用于氧化应激），细胞色素c，APAF1，BAX，Caspase 9，Caspase 3以及BCL2的减少（用于激活凋亡途径），pATM，ATR来结束这种机制。和γH2AX（用于双链断裂），DNA-PK（参与DNA修复）并减少细胞周期调节剂。总之，我们的数据揭示了ROS产生的机制，该机制触发了暴露于ZnO NPs的HaCaT细胞系的凋亡和DNA损伤。