激活Notch信号途径对缺氧/复氧心肌细胞的保护作用

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。

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

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-Dll1 group (Dll1, Delta-like 1, Notch ligand), H/R+OP9-GFP group and H/R+OP9-Dll1 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-Dll1 (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 OP9-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.