Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Department of Animal Sciences and Technology, Shandong Agricultural University, Taian 271018, Shandong, China.
Agriculture and Agri-Food Canada, Lethbridge Research Centre, PO Box 3000, Lethbridge, Alberta, T1J 4B1, Canada.
Toxicology. 2020 Jan 15;429:152337. doi: 10.1016/j.tox.2019.152337. Epub 2019 Nov 21.
Zearalenone (ZEA) contamination of feed affects animal husbandry and the human health. Currently, the molecular mechanism underlying small intestine-related diseases caused by ZEA-induced oxidative stress is not well understood. In this study, we aimed to identify the mechanisms involved in ZEA (0.5-1.5 mg/kg)-induced oxidative stress in the ileum and mesenteric lymph nodes (MLNs) and the role of the Kelch-like erythroid cell-derived protein with CNC homology-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway in post-weaning gilts. Forty post-weaning gilts (Landrace × Yorkshire × Duroc) with an average body weight of 14.01 ± 0.86 kg were randomly allocated to four groups and fed a corn-soybean meal basal diet supplemented with < 0.1, 0.5, 1.0, or 1.5 mg/kg ZEA. The results showed that the activity of total superoxide dismutase and glutathione peroxidase decreased (p < 0.05) linearly and quadratically and that the content of malondialdehyde increased (p < 0.05) quadratically in the ileum and MLNs with increasing ZEA in the diet. Immunohistochemical analysis showed that the expression of Nrf2 and glutathione peroxidase 1 (Gpx1) immunoreactive proteins in the ileum and MLNs were significantly enhanced with increasing ZEA. The relative mRNA and protein expression of Nrf2, Gpx1, quinone oxidoreductase 1 (Nqo1), hemeoxygenase 1 (Ho1), modifier subunit of glutamate-cysteine ligase (Gclm), and catalytic subunit of glutamate-cysteine ligase (Gclc) increased (p < 0.05) linearly and quadratically, and the relative mRNA and protein expression of Keap1 decreased (p < 0.05) linearly and quadratically in the ileum with increasing ZEA concentrations in the diet. Further, the relative mRNA and protein expression of Nrf2 and Gpx1 increased (p < 0.05) linearly and quadratically, and the relative mRNA and protein expression of Nqo1, Ho1, and Gclm decreased (p < 0.05) quadratically in the MLNs as ZEA concentrations increased in the diet. Our results provide valuable genetic information on ZEA-induced oxidative stress in the ileum and MLNs of post-weaning gilts and have elucidated the key regulatory genes involved in the Keap1-Nrf2 signaling pathway. Results indicated that the Keap1-Nrf2 signaling pathway might be a key target to further prevent and treat ZEA-induced injury to the ileum in post-weaning gilts.
玉米赤霉烯酮（ZEA）污染饲料会影响畜牧业和人类健康。目前，ZEA 诱导的氧化应激引起的小肠相关疾病的分子机制尚不清楚。在本研究中，我们旨在确定 ZEA（0.5-1.5mg/kg）诱导的断奶仔猪回肠和肠系膜淋巴结（MLN）氧化应激的机制，以及 Kelch 样红细胞衍生蛋白与 CNC 同源相关蛋白 1（Keap1）-核因子红细胞 2 相关因子 2（Nrf2）信号通路在断奶仔猪中的作用。40 头平均体重为 14.01±0.86kg 的断奶仔猪（长白猪×约克夏猪×杜洛克猪）被随机分为四组，分别饲喂基础玉米-豆粕日粮，添加<0.1、0.5、1.0 或 1.5mg/kg ZEA。结果表明，随着日粮中 ZEA 含量的增加，回肠和 MLN 中总超氧化物歧化酶和谷胱甘肽过氧化物酶的活性呈线性和二次降低（p<0.05），丙二醛含量呈二次增加（p<0.05）。免疫组织化学分析显示，随着日粮中 ZEA 含量的增加，回肠和 MLN 中 Nrf2 和谷胱甘肽过氧化物酶 1（Gpx1）免疫反应蛋白的表达显著增强。随着日粮中 ZEA 浓度的增加，Nrf2、Gpx1、醌氧化还原酶 1（Nqo1）、血红素加氧酶 1（Ho1）、谷氨酸-半胱氨酸连接酶修饰亚基（Gclm）和谷氨酸-半胱氨酸连接酶催化亚基（Gclc）的相对 mRNA 和蛋白表达呈线性和二次增加（p<0.05），Keap1 的相对 mRNA 和蛋白表达呈线性和二次降低（p<0.05）。此外，随着日粮中 ZEA 浓度的增加，Nrf2 和 Gpx1 的相对 mRNA 和蛋白表达呈线性和二次增加（p<0.05），而 Nqo1、Ho1 和 Gclm 的相对 mRNA 和蛋白表达呈二次降低（p<0.05）。我们的结果为断奶仔猪回肠和 MLN 中 ZEA 诱导的氧化应激提供了有价值的遗传信息，并阐明了 Keap1-Nrf2 信号通路中涉及的关键调节基因。结果表明，Keap1-Nrf2 信号通路可能是进一步预防和治疗断奶仔猪 ZEA 诱导回肠损伤的关键靶点。
