甘氨酸对大鼠缺血缺氧心肌细胞凋亡的影响

Effects of Glyeine on apoptosis in murine cardiomyocyte suffering from ischemia and hypoxia

目的明确甘氨酸对缺血缺氧致心肌细胞凋亡过程的影响。方法建立SD乳鼠心肌细胞缺血缺氧模型，分为单纯缺血缺氧组和甘氨酸处理组（培养液中加入终浓度5mmol／L甘氨酸，其余处理同单纯缺血缺氧组）。以SD乳鼠正常心肌细胞作为对照组。3组细胞培养6h后，检测凋亡情况、线粒体跨膜电位及分布情况、线粒体通透性转换孔（mPTP）开放情况及半胱氨酸天冬氨酸蛋白酶3（caspase-3）活性变化。结果（1）细胞凋亡程度：对照组和甘氨酸处理组荧光强度均明显低于单纯缺血缺氧组（P〈0．01）。（2）线粒体跨膜电位：对照组心肌细胞荧光强度为73±4，单纯缺血缺氧组荧光强度（32±7）明显较弱（P〈0．01），甘氨酸处理组荧光强度（52±4）强于单纯缺血缺氧组（P〈0．01）。（3）mPTP开放情况：对照组心肌细胞线粒体荧光强度（90±7）较强，甘氨酸处理组荧光强度（62±8）明显强于单纯缺血缺氧组（27±4，P〈0．01）。（4）caspase-3活性：对照组和甘氨酸处理组均显著低于单纯缺血缺氧组（P〈0．01）。结论甘氨酸对缺血缺氧心肌细胞具有抗凋亡作用，其机制可能与改变线粒体膜电位、减少mPTP开放、减轻钙超载、降低caspase-3活性有关。

Objective To investigate the effects of glycine on apoptosis in murine cardiomyocyte suffering from ischemia and hypoxia. Methods The primary passage of cultured cardiomyocytes from neonatal rats were subjected to ischemia and hypoxia , and the cells were divided into IH（ without other treatment） , and G （ with treatment of 5 mmol/L glycine）groups. Normal murine cardiomycytes served as control （C group）. Cardiomyocytes were cultured for 6 hours in vitro. Apoptosis, mitochondrial membrane potential and its distribution, the condition of mitochondria permeability transition pore （mPTP） were observed with expression of fluoresence intensity . The activity of caspase-3 was observed by Laser Scanning staining. Resuits （ 1 ） Apoptosis ：the fluoresence intensity in IH group was obviously higher than that in G and C groups （ P 〈0.01）. （2） Mitochondrial membrane potential： the fluoresence intensity in IH group was 32 ± 7, which was obviously lower than that in G and C groups （52 ± 4,73 ± 4, respectively, P 〈 0.01 ）. （ 3 ） The condition of mPTP： the fluoresence intensity in IH group was 27 -±4 ,which was obviously lower than that in G and C groups （62±8,90±7,respectively , P 〈0.01）. （4）The activity of capase-3 ：the activity of caspase-3 in IH group was obviouly higher than that in G and C groups （ P 〈 0.01 ）. Conclusion Glycine can inhibit apoptosis in cardiomyocytes subjected to ischemia and hypoxia,and the effect may be attributable to changes in mitochondrial membrane potential, lessening opening of mPTP, alleviation of calcium overload ,and decrease in activity of caspase-3.