钙池排空操纵的外钙内流决定甘草诱导MGC-803细胞凋亡

 用 EGTA螯合胞外 Ca2 +和异搏定抑制钙通道 ,研究胞外 Ca2 +在甘草诱导 MGC- 80 3细胞中的作用 .流式细胞仪检测凋亡峰和 DNA ladder分析均表明 ,EGTA和异博定阻断细胞凋亡 .分别以 PI或 Rh1 2 3活染后的相应荧光强度表示细胞膜通透性和线粒性膜电位 (ΔΨm) .结果表明 ,细胞膜通透性增强和线粒体 ΔΨm 下降均为细胞凋亡的早期事件 ,EGTA和异博定均可抑制细胞膜通透性增强 ,但 EGTA促进线粒体 ΔΨm 下降 ,而异博定作用相反 .进一步经 PI和 Hoechst33342荧光双染后同时观察细胞膜通透性和细胞核形态 .结果表明 ,凋亡细胞均可 PI着色 ,EGTA和异博定完全阻断染色质凝聚 ,但不能完全抑制细胞膜通透性变化 .借助 Ca2 +探针 Fluo- 3/AM研究凋亡时胞内游离钙的时相变化 ,发现 Ca2 +升高也是细胞凋亡的早期事件 . EGTA和异博定轻微促进凋亡早期 Ca2 +升高 ,但抑制随后 Ca2 +的继续升高 .所有结果提示 ,钙池排空操纵的外 Ca2 +内流在甘草诱导 MGC- 80 3细胞凋亡中发挥决定性的作用 .

Ca~(2+)Store Depletion\|operated Ca~(2+)Influx Determines the Apoptosis of MGC-803 Cells Induced by Extract of Glycyrrhiza uralensis Fisch

By using extracellular calcium chelator EGTA and plasma membrane calcium\|channel blocker verapamil,the role of extracellular Ca 2+ was studied in the apoptosis of MGC\|803 induced by extract of Glycyrrhiza uralensis Fisch(EGUF).Both flow cytometry and DNA ladder analysis demonstrated that the apoptosis of MGC\|803 was blocked by EGTA and verapamil.Without cell fixation,staining of PI or Rh123 respectively revealed that increase of membrane permeability and decrease of mitochondrial membrane potential were early events of apoptosis.Both EGTA and verapamil inhibibed the increase of membrane permeability.However,the opposing effects of EGTA and verapamil on the decrease of mitochondrial membrane potential were observed:EGTA promoted but verapamil inhibited it.Fluorescence microscope observation after double staining of PI and Ho33342 displayed that all apoptotic cells were PI\|permeable,and EGTA and verapamil completely blocked the chromatin condensation of apoptosis and just partially inhibited the change of membrane permeability.The time\|lapse change of intracellular Ca 2+ in the apoptosis was detected with Ca 2+ probe Flou\|3/AM.It showed that increase of intracellular Ca 2+ also occurred early in the apoptosis of MGC\|803,and EGTA and verapamil slightly promoted early increase of intracellular Ca 2+ but inhibited further increase following that.All the data suggest that Ca 2+ store depletion\|operated Ca 2+ influx plays a pivotal role in the apoptosis of MGC\|803 cells induced by EGUF.