Reproduction, Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido, Japan.
Department of Endocrine Pharmacology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan.
Biol Reprod. 2021 Nov 15;105(5):1114-1125. doi: 10.1093/biolre/ioab143.
Heat stress adversely affects the reproductive function in cows. Although a relationship between heat stress and oxidative stress has been suggested, it has not been sufficiently verified in bovine endometrial epithelial cells. Here, we investigated whether oxidative stress is induced by heat stress in bovine endometrial epithelial cells under high temperature. Luciferase reporter assays showed that the reporter activity of heat shock element and antioxidant responsive element was increased in endometrial epithelial cells cultured under high temperature compared to that in cells cultured under basal (thermoneutral) temperature. Also, nuclear factor, erythroid 2 like 2 (NFE2L2), a master regulator of cellular environmental stress response, stabilized and the expression levels of antioxidant enzyme genes increased under high temperature. Immunostaining confirmed the nuclear localization of NFE2L2 in endometrial epithelial cells cultured under high temperature. Quantitative polymerase chain reaction analysis showed that the expression levels of representative inflammatory cytokine genes, such as prostaglandin-endoperoxide synthase 2 (PTGS2) and interleukin 8, were significantly decreased in endometrial epithelial cells cultured under high temperature compared to those in cells cultured under basal temperature. Thus, our results suggest that heat stress induces oxidative stress, whereas NFE2L2 plays a protective role in bovine endometrial epithelial cells cultured under heat stress conditions.
热应激会对奶牛的生殖功能产生不利影响。虽然已经有人提出热应激与氧化应激之间存在关系，但在牛子宫内膜上皮细胞中尚未得到充分验证。在这里，我们研究了高温下牛子宫内膜上皮细胞是否会因热应激而产生氧化应激。荧光素酶报告基因分析显示，与基础（体温正常）温度下培养的细胞相比，高温下培养的子宫内膜上皮细胞的热休克元件和抗氧化反应元件的报告基因活性增加。此外，核因子，红细胞 2 样 2（NFE2L2），一种细胞环境应激反应的主要调节剂，在高温下稳定，抗氧化酶基因的表达水平增加。免疫染色证实了 NFE2L2 在高温下培养的子宫内膜上皮细胞中的核定位。定量聚合酶链反应分析显示，与基础温度下培养的细胞相比，高温下培养的子宫内膜上皮细胞中代表性炎症细胞因子基因，如前列腺素内过氧化物合酶 2（PTGS2）和白细胞介素 8 的表达水平显著降低。因此，我们的结果表明，热应激会诱导氧化应激，而 NFE2L2 在牛子宫内膜上皮细胞在热应激条件下培养时发挥保护作用。
