College of Animal Science, Anhui Science and Technology University, Fengyang, 233100, Anhui, China.
Anhui Province Key Laboratory of Animal Nutritional Regulation and Health, Anhui Science and Technology University, Fengyang, 233100, Anhui, China.
Biol Trace Elem Res. 2022 Feb;200(2):728-739. doi: 10.1007/s12011-021-02673-7. Epub 2021 Mar 18.
Heat stress (HS)-induced apoptosis in Leydig cells is mediated by various molecular mechanisms, including endoplasmic reticulum (ER) stress. Zinc, an inorganic mineral element, exhibits several cytoprotective properties, but its potential protective action against Leydig cell apoptosis and the related molecular mechanisms has not been fully elucidated. In this study, we evaluated the effects of zinc sulfate, a predominant chemical form of zinc, exerted on cell viability, apoptosis, and testosterone production in HS-treated TM3 Leydig cells and investigated the underlying signaling pathways. HS treatment inhibited cell viability and induced apoptosis, which was accompanied by the induction of the activity of caspase 3, an executioner of apoptosis, involved in the expression of pro-apoptotic protein B cell lymphoma 2-associated X protein (Bax), and in the reduction of the expression of anti-apoptotic protein B cell lymphoma 2 (Bcl-2), thereby activating ER stress marker protein expression (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP)). However, zinc sulfate led to the attenuation of deleterious effects, including increases in apoptosis, caspase-3 activity, Bax, GRP78, and CHOP expression, and decreases in cell viability and Bcl-2 protein expression in cells treated with HS or thapsigargin (an ER stress activator). Furthermore, 4-phenylbutyric acid (an ER stress inhibitor) treatment markedly alleviated the HS-induced adverse effects in cells exposed to HS, which was similar to zinc sulfate. Additionally, zinc sulfate supplementation in the culture medium effectively restored the HS-induced decrease in testosterone levels in HS-treated cells. In summary, these findings indicate that HS triggers apoptosis in TM3 Leydig cells via the ER stress pathway and that zinc confers protection against these detrimental effects. This study provides new insights into the benefits of using zinc against HS-induced apoptosis and cell injury.
热应激（HS）诱导的睾丸间质细胞凋亡是通过多种分子机制介导的，包括内质网（ER）应激。锌是一种无机矿物质元素，具有多种细胞保护特性，但它对睾丸间质细胞凋亡的潜在保护作用及其相关的分子机制尚未完全阐明。在这项研究中，我们评估了硫酸锌（锌的主要化学形式）对 HS 处理的 TM3 睾丸间质细胞活力、凋亡和睾酮产生的影响，并研究了潜在的信号通路。HS 处理抑制细胞活力并诱导凋亡，同时诱导凋亡执行器 caspase-3 的活性，涉及促凋亡蛋白 B 细胞淋巴瘤 2 相关 X 蛋白（Bax）的表达减少和抗凋亡蛋白 B 细胞淋巴瘤 2（Bcl-2）的表达减少，从而激活 ER 应激标志物蛋白的表达（葡萄糖调节蛋白 78（GRP78）和 CCAAT/增强子结合蛋白同源蛋白（CHOP））。然而，硫酸锌导致有害影响的减弱，包括凋亡增加、caspase-3 活性、Bax、GRP78 和 CHOP 表达增加，细胞活力降低和 Bcl-2 蛋白表达降低在 HS 或他普西庚（一种 ER 应激激活剂）处理的细胞中。此外，4-苯基丁酸（一种 ER 应激抑制剂）处理显著减轻了 HS 诱导的 HS 暴露细胞的不良影响，类似于硫酸锌。此外，硫酸锌补充培养基可有效恢复 HS 处理细胞中 HS 诱导的睾酮水平下降。综上所述，这些发现表明 HS 通过 ER 应激途径触发 TM3 睾丸间质细胞凋亡，而锌对这些有害作用具有保护作用。这项研究为使用锌对抗 HS 诱导的凋亡和细胞损伤提供了新的见解。
