Urantide对缺血/再灌注损伤诱导的心肌细胞凋亡的影响(英文)

目的探讨urantide对大鼠心肌缺血/再灌注(I/R)或缺氧/复氧损伤(H/R)诱导的心肌细胞凋亡的影响及其相关机制。方法①在体实验采用冠状动脉左前降支缺血30 min/灌注60 min法建立大鼠在体心肌I/R模型。Urantide 3,10和30μg.kg-1分别于缺血前10 min经舌下静脉给药。TUNEL法检测心肌细胞凋亡,免疫组织化学方法检测心肌细胞内Bcl-2和Bax蛋白的表达水平。②离体实验乳大鼠心肌细胞行缺氧3 h/复氧3 h处理制备H/R模型。Urantide 0.1,1和10 nmol.L-1分别于缺氧前加入。Ho-echst33258染色和流式细胞术检测心肌细胞凋亡。结果①在体实验与假手术组相比,I/R组TUNEL阳性细胞数量明显升高(P<0.01);Bcl-2蛋白表达量轻度升高,但无统计学差异,Bax蛋白表达量显著升高(P<0.01),Bcl-2/Bax比值明显降低(P<0.01)。与I/R组相比,urantide 10,30μg.kg-1组心肌凋亡细胞显著降低,分别较模型组降低36.6%和57.2%(P<0.05);Bax蛋白表达量显著降低(P<0.05),Bcl-2/Bax比值明显升高(P<0.05);同时,urantide 30μg.kg-1组Bcl-2蛋白表达量也明显升高(P<0.05)。②离体实验与正常对照组相比,H/R组细胞凋亡率明显升高(P<0.01);Hoechst33258结果显示,与模型组相比,uran-tide 0.1,1和10 nmol.L-1组细胞凋亡率分别显著降低了27.9%,59.0%和75.4%(P<0.05)。流式细胞术结果显示,urantide 1和10 nmol.L-1组细胞凋亡率显著降低,分别较H/R模型组降低32.8%和64.7%(P<0.01)。结论 Urantide可减轻I/R或H/R损伤诱导的心肌细胞凋亡,其机制可能与增加Bcl-2蛋白表达,降低Bax蛋白表达有关。

Effect of urantide on myocardial apoptosis in rats induced by ischemia/reperfusion injury

OBJECTIVE To investigate the protective effect of urantide on myocardial apoptosis in rats induced by ischemia/reperfusion (I/R) or hypoxia/reoxygenation (H/R) injury and explore the underlying mechanism. METHODS ① In vivo test A rat myocardial I/R injury model was induced by ligating and untying the left anterior descending coronary artery with occlusion 30 min/reperfusion 60 min. Urantide 3, 10 and 30 μg·kg-1 was iv given 10 min before ischemia. TUNEL labeling was used for apoptosis measurement in myocardium. Immu-nohistochemical assay was used for Bcl-2 and Bax proteins expression detection. ② In vitro test An H/R cell model was set up by 3 h hypoxia/3 h reoxygenation. Urantide 0.1,1 and 10 nmol·L-1 was added just before hy-poxia, respectively. Hoechst33258 assay and flow cytometric techniques were used to detect apoptotic cells. RESULTS ① In vivo test Compared with sham group, the number of TUNEL-positive cells in I/R model group significantly increased (P<0.01) ; Bcl-2 protein expression slightly increased with no significant difference, Bax protein expression markedly increased ( P < 0. 01 ) , while Bcl-2/Bax ratio in I/R model group significantly decreased (P <0.01). Compared with I/R model group, the number of TUNEL-positive cells in urantide 10 and 30 μg·kg-1 groups was significantly decreased by about 36.6% and 57. 2% (P<0.05) ; Bax protein expression markedly decreased ( P <0.05 ) , while Bcl-2/Bax ratio was significantly augmented ( P <0.05 ). Urantide 30 u,g-kg"1 also markedly increased Bcl-2 protein expression(P <0.05). ② In vitro test Compared with normal control group, the apoptosis rate in H/R model group significantly increased (P<0. 01). Hoechst33258 assay revealed that urantide 0.1, 1 and 10 nmol·L-1 reduced H/R-induced apoptotic nuclei by about 27.9% , 59.0% and 75. 4% , respectively (P <0.05). Flow cytometric techniques showed that the apoptosis rate was significantly reduced by about 32.8% and 64. 7% with administration of urantide 1 and 10 nmol·L-1 (P < 0. 01). CONCLUSION Urantide exerts an inhibitory effect on I/R or H/R-induced apoptosis by increasing Bcl-2 protein expression and decreasing Bax protein expression.