Mercury (Hg) is a hazardous metal, poses environmental problems with severe human health effects; whereas zinc (Zn) is an essential micronutrient with antioxidant properties. The purpose of this research was to investigate the effect of Zn on inorganic Hg-induced cytotoxicity in the PC12 cells. The cells were treated with HgCl₂ (5 μM) for 48 h with/without 1 h prior ZnCl₂-treatment (100 μM) and deliberated for further analysis. After 48 h of incubation with only Hg²⁺, the cell showed reduced cell viability, compromised cell membrane, DNA degradation, depleted glutathione level, ROS generation and drastically increased apoptosis. Subsequently, Hg²⁺-treated cells demonstrated a significant downregulation of akt, mTOR, ERK1, Nrf2, HO1, Bcl-2, Bcl-xL, and upregulation of p53, Bax, cytochrome c and cleaved caspase 3, indicating intrinsic apoptosis induction. However, cells pretreated with Zn²⁺ before Hg²⁺-exposure showed a significant improvement in cell viability, cell membrane, DNA damage, glutathione level, ROS amount and apoptotic cells, with a significant upregulation in mTOR, akt, ERK1, Nrf2, HO1, Bcl-2 and Bcl-xL, and downregulation in p53, Bax, cytochrome c and cleaved caspase 3, indicating inhibition of apoptosis. The findings suggested that Zn²⁺-pretreatment not only improves glutathione content but also induces activation of Nrf2-HO1 pathway, which would tend to suppress Hg-cytotoxicity.

汞（Hg）是一种有害金属，会给环境造成严重影响，并危害人类健康。而锌（Zn）是具有抗氧化特性的必需微量营养素。这项研究的目的是研究锌对PC12细胞中无机汞诱导的细胞毒性的影响。在ZnCl _2处理（100μM）之前/不进行1 h的情况下，将细胞用HgCl ₂（5μM）处理48 h，并进行进一步分析。仅用Hg ²⁺孵育48小时后，细胞显示出降低的细胞活力，受损的细胞膜，DNA降解，谷胱甘肽水平降低，ROS生成和凋亡急剧增加。随后，汞²⁺经处理的细胞显示出akt，mTOR，ERK1，Nrf2，HO1，Bcl-2，Bcl-xL的显着下调，以及p53，Bax，细胞色素c和裂解的胱天蛋白酶3的上调，表明内在凋亡诱导。然而，细胞预处理用Zn ²⁺之前汞柱²⁺ -曝光显示在细胞活力，细胞膜，DNA损伤，谷胱甘肽水平，ROS量和凋亡细胞一个显著改善，在mTOR的一个显著上调，AKT，ERK1，Nrf2的， HO1，Bcl-2和Bcl-xL以及p53，Bax，细胞色素c和裂解的caspase 3中的下调，表明细胞凋亡受到抑制。研究结果表明，Zn ²⁺预处理不仅提高了谷胱甘肽的含量，而且还诱导了Nrf2-HO1途径的活化，这将倾向于抑制Hg细胞毒性。