MnTMPyP通过抑制氧化应激和内质网应激减轻百草枯致肺上皮细胞损伤

MnTMPyP Reduces Paraquat-Induced Lung Epithelial-Like Cell Injury by Inhibiting Oxidative Stress and Endoplasmic Reticulum Stress

目的探讨锰(Ⅲ)-四(4-N-甲基吡啶基)卟啉(MnTMPyP)对百草枯(PQ)致肺上皮细胞损伤是否具有保护作用及相关机制。方法体外培养人肺泡Ⅱ型上皮样细胞A549细胞,以超氧化物歧化酶的模拟物MnTMPyP为干预因素。实验分为4组:对照组,加入RPMI 1640培养液;MnTMPyP组,加入MnTMPyP 10μmol/L;PQ组,加入PQ 750μmol/L;PQ+MnTMPyP组,MnTMPyP10μmol/L预处理90 min,再加入PQ 750μmol/L。各组细胞处理24 h后检测相关指标。MTT法检测细胞活性;流式细胞术检测活性氧(ROS)、细胞质内Ca^(2+)水平;紫外比色法检测谷胱甘肽还原酶活性;Western blotting检测内质网应激蛋白葡萄糖调节蛋白78(Grp78)、C/EBP同源蛋白(CHOP)蛋白的表达。结果与对照组相比,MnTMPyP组检测指标的变化无统计学意义;PQ组细胞活性降低,ROS产生显著增加,细胞质内Ca^(2+)水平明显升高,谷胱甘肽还原酶活性明显降低,Western blotting显示内质网应激蛋白Grp78、CHOP表达量均显著增加。与PQ组相比,PQ+MnTMPyP组细胞活性增加,ROS产生减少,细胞质内Ca^(2+)水平降低,谷胱甘肽还原酶活性增加,Grp78、CHOP蛋白表达量均显著减少。结论 MnTMPyP有效减轻PQ诱导的肺上皮细胞损伤,其机制与拮抗PQ引起的氧化应激和内质网应激有关。

Objective To investigate the protective effect and underlying mechanism of the superoxide dismutase mimic,manganese (Ⅲ) tetrakis( 1-methyl-4-pyridyl) porphyrin pentachloride( MnTMPyP),on paraquat( PQ)-induced lung epithelial-like cell injury. Methods Alveolar epithelial-like cells( A549) were pretreated with 10 μmol/L of MnTMPyP for 1.5 h and then cultured with or without PQ (750 μmol/L) for 24 h. Cell survival was determined using the MTT assay. Reactive oxygen species( ROS) production and Ca^2+ levels were measured using flow cytometry. Glutathione reductase( GR) activity was determined using spectrophotometry. Expressions of the endoplasmic reticulum( ER) stress proteins,glucose regulatory protein 78( Grp78) and C/EBP homologous protein( CHOP),were measured using Western blotting. Results Cell viability and GR activity were decreased,but ROS production,cytoplasmic Ca^2+ levels,and expressions of Grp78 and CHOP were all increased in the PQ group compared to those in the control group. There were no statistically significant changes in the MnTMPyP group. Cell viability and GR activity were increased,while ROS production,cytoplasmic Ca^2+ levels, and expressions of Grp78 and CHOP were all significantly reduced in the MnTMPyP group compared to those in the PQ group. Conclusion MnTMPyP effectively reduced PQ-induced lung epithelial-like cell injury,and the underlying mechanism is related to antagonism of PQ-induced ER stress and oxidative stress.