Effect of urantide on myocardial apoptosis in rats induced by ischemia/reperfusion injury / 中国药理学与毒理学杂志

ABSTRACT

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-kg1 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.