To understand the role of microRNA-141 (miR-141) in hypoxia/reoxygenation (H/R)-induced PC12 cell injury via modulation of Keap1/Nrf2 signaling pathway. PC12 cells were divided into Control, H/R, H/R + miR-141 mimics, H/R + NC, H/R + miR-141 inhibitor, H/R + siKeap1 and H/R + miR-141 inhibitors+siKeap1 groups. The expression of miR-141 and Keap1/Nrf2 pathway was measured by qRT-PCR and western blotting, cell viability evaluated by MTT assay while cell apoptosis tested by flow cytometry. Besides, MDA (malondialdehyde), SOD (Super Oxide Dismutase) and LDH (lactate dehydrogenase) levels were determined. DCFH-DA and JC-1 staining were used to measure ROS and mitochondrial membrane potential (MMP) respectively. Compared with Controls, PC12 cells induced by H/R exhibited decreased cell viability and increased cell apoptosis rate, with elevated MDA, LDH and ROS and reduced SOD levels; and meanwhile, MMP and miR-141 expression were declined, whereas cytoplasmic Nrf2 levels were enhanced with the downregulated nuclear Nrf2 level (all P < 0.05). However, these cells treated with miR-141 mimics and siKeap1 showed obvious improvement in H/R-induced cell injury, while miR-141 inhibitors presented significantly aggravated cell injury (both P < 0.05). Besides, siKeap1 can reverse the effect of miRNA-141 inhibitors on aggravating H/R-induced PC12 cell injury. miR-141-mediated Keap1/Nrf2 signaling pathway to promote cell viability, inhibit cell apoptosis and reduce oxidative stress of PC12 cells, thereby alleviating H/R-induced cell injury.

中文翻译：

---

MicroRNA-141通过调节Keap1-Nrf2信号通路，保护PC12细胞免受缺氧/复氧诱导的损伤。

通过调节Keap1 / Nrf2信号通路来了解microRNA-141（miR-141）在缺氧/复氧（H / R）诱导的PC12细胞损伤中的作用。PC12细胞分为对照组，H / R，H / R + miR-141模拟物，H / R + NC，H / R + miR-141抑制剂，H / R + siKeap1和H / R + miR-141抑制剂+ siKeap1组。通过qRT-PCR和western blotting检测miR-141和Keap1 / Nrf2途径的表达，MTT法评价细胞活力，流式细胞术检测细胞凋亡。此外，测定了丙二醛（MDA），超氧化物歧化酶（SOD）和乳酸脱氢酶（LDH）的水平。DCFH-DA和JC-1染色分别用于测量ROS和线粒体膜电位（MMP）。与对照组相比，H / R诱导的PC12细胞表现出降低的细胞活力和细胞凋亡率，同时MDA升高，LDH和ROS以及SOD含量降低；同时，随着核Nrf2水平的下调，MMP和miR-141表达下降，而胞质Nrf2水平升高（均P <0.05）。然而，用miR-141模拟物和siKeap1处理的这些细胞在H / R诱导的细胞损伤中表现出明显的改善，而miR-141抑制剂则显着加重了细胞损伤（均P <0.05）。此外，siKeap1可以逆转miRNA-141抑制剂对加重H / R诱导的PC12细胞损伤的作用。miR-141介导的Keap1 / Nrf2信号通路可促进细胞活力，抑制细胞凋亡并降低PC12细胞的氧化应激，从而减轻H / R诱导的细胞损伤。而胞质Nrf2水平则随着核Nrf2水平的下调而升高（所有P <0.05）。然而，这些用miR-141模拟物和siKeap1处理的细胞在H / R诱导的细胞损伤中表现出明显的改善，而miR-141抑制剂则显着加重了细胞损伤（均P <0.05）。此外，siKeap1可以逆转miRNA-141抑制剂对加重H / R诱导的PC12细胞损伤的作用。miR-141介导的Keap1 / Nrf2信号通路可促进细胞活力，抑制细胞凋亡并降低PC12细胞的氧化应激，从而减轻H / R诱导的细胞损伤。而胞质Nrf2水平则随着核Nrf2水平的下调而升高（所有P <0.05）。然而，用miR-141模拟物和siKeap1处理的这些细胞在H / R诱导的细胞损伤中表现出明显的改善，而miR-141抑制剂则显着加重了细胞损伤（均P <0.05）。此外，siKeap1可以逆转miRNA-141抑制剂对加重H / R诱导的PC12细胞损伤的作用。miR-141介导的Keap1 / Nrf2信号通路可促进细胞活力，抑制细胞凋亡并降低PC12细胞的氧化应激，从而减轻H / R诱导的细胞损伤。siKeap1可以逆转miRNA-141抑制剂对加重H / R诱导的PC12细胞损伤的作用。miR-141介导的Keap1 / Nrf2信号通路可促进细胞活力，抑制细胞凋亡并降低PC12细胞的氧化应激，从而减轻H / R诱导的细胞损伤。siKeap1可以逆转miRNA-141抑制剂对加重H / R诱导的PC12细胞损伤的作用。miR-141介导的Keap1 / Nrf2信号通路可促进细胞活力，抑制细胞凋亡并降低PC12细胞的氧化应激，从而减轻H / R诱导的细胞损伤。