College of Life Sciences, Tianjin Key Laboratory of Animal and Plant Resistance, Tianjin Normal University, Tianjin 300387, China.
Tianjin Key Laboratory of Agricultural Animal Breeding and Healthy Husbandry, College of Animal Science and Veterinary Medicine, Tianjin Agricultural University, Tianjin 300384, China.
Oxid Med Cell Longev. 2021 Jul 21;2021:4464002. doi: 10.1155/2021/4464002. eCollection 2021.
(CB) is a naturally occurring probiotic compound that can alleviate the oxidative damage induced by enterotoxigenic K88 (ETEC K88) in porcine intestinal epithelial (IPEC-J2) cells. In this study, we investigate the molecular mechanism underlying this effect. Based on cell viability, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX) assessments, the optimal concentration of ETEC K88 was determined to be 1 × 10 cfu/mL. Viable bacteria counts in cells pretreated with CB and then infected with ETEC K88 show that CB can adhere to IPEC-J2 cells and that optimal adhesion is achieved at the multiple infection index (MOI) of 50 at 3 h of pretreatment. The results of qPCR indicate that although ETEC significantly decreases the expression levels of antioxidant enzymes regulated by NF-E2-related factor 2 (Nrf2) compared to the control group, CB reverses this effect. To confirm that Nrf2 is directly involved in the mechanism by which CB alleviates oxidative stress, siRNA was used to silence the expression of gene in IPEC-J2 cells. Compared to the NC+ETEC and siRNA+ETEC groups, the expressions of , , , and in the NC+CB+ETEC and siRNA+CB+ETEC groups are significantly increased at 12 h and 24 h. This shows that CB can reduce ETEC K88-induced oxidative damage in IPEC-J2 cells by activating the expression of antioxidant enzymes implicated in the Kelch-like ECH-associated protein-1- (Keap1-) Nrf2/antioxidant response element (ARE) signaling pathway.
（CB）是一种天然存在的益生菌化合物，可减轻肠产毒性大肠杆菌（ETEC K88）在猪肠上皮（IPEC-J2）细胞中诱导的氧化损伤。在这项研究中，我们研究了这种作用的分子机制。基于细胞活力、丙二醛（MDA）、超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GPX）评估，确定 ETEC K88 的最佳浓度为 1×10cfu/mL。用 CB 预处理然后感染 ETEC K88 的细胞中的活菌计数表明，CB 可以黏附到 IPEC-J2 细胞上，并且在预处理 3 小时时，最佳黏附在多重感染指数（MOI）为 50。qPCR 的结果表明，尽管 ETEC 与对照组相比，显著降低了 NF-E2 相关因子 2（Nrf2）调节的抗氧化酶的表达水平，但 CB 逆转了这种作用。为了证实 Nrf2 直接参与 CB 缓解氧化应激的机制，使用 siRNA 沉默 IPEC-J2 细胞中基因的表达。与 NC+ETEC 和 siRNA+ETEC 组相比，NC+CB+ETEC 和 siRNA+CB+ETEC 组在 12 小时和 24 小时时，、、和的表达明显增加。这表明，CB 可以通过激活与 Kelch-like ECH-associated protein-1-（Keap1-）Nrf2/抗氧化反应元件（ARE）信号通路相关的抗氧化酶的表达，减少 ETEC K88 诱导的 IPEC-J2 细胞中的氧化损伤。
