激活Notch信号途径对缺氧/复氧心肌细胞的保护作用

Protective effects of Notch signaling pathway activation on hypoxia/reoxygenation cardiomyocytes

目的观察激动Notch信号途径抗心肌细胞缺氧/复氧(hypoxia/reoxygenation,H/R)损伤的作用及其可能的机制。方法将心肌细胞分为4组:常氧+OP9-GFP(OP9为稳转细胞系; GFP:green fluorescent protein为绿色荧光蛋白)组,常氧+OP9-Dll1(Dll1:Delta-like 1为Notch的配体)组,H/R+OP9-GFP组,H/R+OP9-Dll1组。用流式细胞仪检测心肌细胞凋亡,并应用荧光探针DCFH-DA检测细胞内活性氧簇(reactive oxygen species,ROS)水平的变化。结果 H/R后心肌细胞的凋亡水平增高(P <0. 01);与表达Dll1的OP9细胞系共培养,则可显著抑制心肌细胞的凋亡(P <0. 01); H/R增高的心肌细胞ROS水平(P <0. 05,P <0. 01)可以被共培养的OP9细胞系生成的Dll1显著降低(P <0. 05,P <0. 01);应用百草枯可促进ROS的生成,而显著抑制Dll1激活心肌Notch信号途径的抗H/R凋亡效应(P <0. 01)。结论激活Notch信号途径,具有抗H/R后心肌损伤的作用,该作用可能与降低ROS水平有关。

AIM To observe the effect of stimulation of the Notch signaling pathway on apoptosis induced by myocardial hypoxia/reoxygenation （H/R）. METHODS Cardiac myocytes were divided into four groups： Normoxia ＋OP9-GFP group （OP9, stable cell line; GFP, green fluorescent protein）, Normoxia ＋ OP9-Dlll group （ Dill, Delta-like 1, Notch ligand）, H/R ＋ OP9-GFP group and H/R ＋ OP9-Dlll group. Apoptotic cells were observed by flow cytometry and intracellular reactive oxygen species （ROS） levels were assayed by fluorescence probe DCFH-DA. RESULTS The apoptotic cells significantly increased after hypoxia/reoxygenation （P 〈0. 01）. However, the apoptotic cells decreased when the cardiac myocytes were co-cultured with OP9-Dlll （P 〈 0. 01 ）, which produced Notch ligands. Intracellular ROS levels,which were significantly increased after hypoxia/reoxygenation （P 〈 0.01 ）, were reduced by co-cultured oPg-Dll （P 〈 0. 01 ）. Paraquat used to increase intracellular ROS significantly inhibited anti-apoptotic effects of the Notch pathway after hypoxia/reoxygenation （ P 〈 0. 01 ）. CONCLUSION Activation of the Notch pathway after hypoxia/reoxygenation elicits anti-apoptotic effects on cardaic myocytes, which is related to decreased intracellular ROS levels.