镉诱导HEK293细胞胞内钙稳态的失调引发细胞凋亡

目的　研究镉诱导HEK2 93细胞钙稳态失调及其引发细胞凋亡的机制。方法　通过吖啶橙 /溴乙锭双荧光染色法检测细胞凋亡 ,并通过MTT法检测细胞生长抑制 ;以Fluo 3/AM和Fura 2 /AM为探针检测胞浆内游离钙离子浓度 ([Ca2 +]i)的变化 ;使用钙调磷酸酶试剂盒测定镉对钙调磷酸酶活性的影响。结果　镉诱导HEK2 93细胞的凋亡和生长抑制呈浓度依赖性 ;镉通过引发胞内钙库的释放后引起胞外钙离子内流 ;钙信号阻断剂能显著地抑制镉引起的细胞凋亡 ;镉使胞内钙调磷酸酶的活性显著增加。结论　 [Ca2 +]i 升高使钙调磷酸酶活化可能在镉引发细胞凋亡过程中起重要作用。

Apoptosis triggered by disequilibrium of intracellular calcium homeostasis induced by cadmium in HEK293 cells

AIM To study the mechanism of cadmium induced apoptosis in HEK293 cells. METHODS By utilizing acridine orange/ethidium bromide double fluorescent dye staining to detect the apoptosis and by using MTT to detect the growth inhibition; fluorescent dye Fluo 3/AM and Fura 2/AM were used to test the change in intracellular free calcium; the effect of cadmium on calcineurin activity was measured by a calcineurin test kit. RESULTS Cadmium caused apoptosis and growth inhibition in a concentration dependent manner, and initiated a rapid release of Ca 2 from Ca 2 pool followed by the influx of the extracellular Ca 2 in HEK293 cells. The result also revealed that some blockers of the calcium signal prevented cadmium inducing apoptosis and that the activity of calcineurin was enhanced by cadmium. CONCLUSION The activation of calcineurin by increased [Ca 2 ] i plays an essential role in the process of cadmium induced apoptosis.