核转录因子在肿瘤坏死因子-α所致内皮细胞凋亡中的作用  

The role of NF-kB in the TNF-α-induced endothelial cell apoptosis

作　　者：钟林[1] 尢家騄[1] 孙去病[1] 罗正曜[1] 

机构地区：[1]湖南医科大学病理生理学教研室,长沙410078

出　　处：《中华医学杂志》1999年第11期863-866,共4页National Medical Journal of China

摘　　要：目的探讨肿瘤坏死因子-α（TNF-α）是否通过信号传导系统－核转录因子（NF-kB）的激活，导致诱导型一氧化氮合酶（iNOS）表达增加，引起内皮细胞凋亡。方法体外培养牛肺动脉内皮细胞，观察iNOS抑制剂一氨基胍，以及NF－kB抑制剂－吡咯烷二硫氨基甲酸盐（PDTC）对TNF-α所致内皮细胞凋亡的影响，观察细胞形态学变化、用DNA电泳及DNA断裂百分率确定细胞凋亡情况；Westernblot分析内皮细胞经TNF-α损伤后iNOS合成及I-kBα的变化；凝胶滞留法检测NF-kB活性。结果TNF-α以剂量和时间依赖性地引起内皮细胞凋亡，TNF-α2500U／ml处理24小时后DNA断裂百分率为（18．0±4．3）％。而氨基胍及PDTC可明显抑制TNF-α所致的内皮细胞凋亡，2、4、10mmol／L氨基胍所致内皮细胞DNA断裂百分率分别为（10．0±2．2）％、（7．8±1．2）％、（8．2±1．3）％。内皮细胞经TNF-α损伤后，I-kBα下降而iNOS合成增加，NF-kB活性增强。结论TNF-α所致内皮细胞凋亡与I-kBα降解，NF-kB活化，导致了iNOS表达增加，与大量一氧化氮释放有关。Objective To investigate whether TNF-α could activate the signaling pathway-NF-kB/I-kBα rquired for the expression of inducible nitric oxide synthase (iNOS) to induce endothelial cell apoptosis by nitric oxide (NO). Methods Aminoguanidine (AG, an inhibitor of iNOS) and Pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-kB ) were evaluated for their influence on the apoptosis of cultured bovine pulmonary artery endothelial cells (BPAEC) induced hy TNF-α. Apoptosis was confirmed by morphology, ultrastructural observation, agarose gel electrophoresis of DNA, and percentage of DNA fragmentation. Westem blot analyses were used to detect the expression of iNOS and the levels of I-kBα in BPAEC exposed to TNF-α. Electrophyoretic mobility shift assays (EMSA) were used to determinate the activity of NF-kB in BPANC. Results TNF-αinduced BPAEC apoptosis (18. 0±4. 3) % in a concentration- and time-dependent manner. Both AG and PDTC attenuated the apoptosis of BPAEC induced by TNF-α, with peventages of DNA fragmentation in 2、4、10 mmol/L AG being (10.0±2.2)%, (7.8±1. 2)% and (8.2±1. 3) % vespectively. In BPAEC after TNF-α exposure, Western blot analyses revealed the expression of iNOS and the decrease in I-kBα. EMSA demonstrated an impermanency increase in NF-kB binding activity. Conclusions TNF-α can induce endothelial cell apoptosis by NO, which is produced by increasing iNOS expression and activating the signal pathway-NF-kB.

关 键 词：脱噬作用 肿瘤坏死因子 一氧化氮 病理生理 

分 类 号：R363[医药卫生—病理学]