钙稳态失衡在镉诱导大鼠大脑皮质神经细胞凋亡中的作用

Effect of the disequilibrium of calcium homeostasis on the apoptosis of rat's primary cultured cerebral cortical neurons induced by cadmium

用不同浓度醋酸镉(0、5、10、20μmol/L)以及细胞内钙离子螯合剂BAPTA-AM(10μmol/L)单独或联合作用于大鼠大脑皮质神经细胞12h,利用流式细胞仪检测细胞凋亡率、细胞内[Ca2+]i、活性氧(ROS)水平以及线粒体膜电位(ΔΨm)。结果显示,与对照组相比,各镉染毒组细胞凋亡率、细胞内[Ca2+]i和ROS水平显著或极显著升高(P<0.05或P<0.01),ΔΨm显著或极显著降低(P<0.05或P<0.01)。BAPTA-AM联合组与相应镉染毒组相比,细胞凋亡率、细胞内[Ca2+]i和ROS水平降低,ΔΨm升高,部分组间差异显著或极显著(P<0.05或P<0.01)。结果表明,镉可诱导大脑皮质神经细胞凋亡,细胞内钙稳态失衡在镉诱导大脑皮质神经细胞凋亡中起着重要作用,凋亡机理可能与细胞内钙超载引起ROS水平升高和ΔΨm下降有关。

To investigate the effect of the disequilibrium of calcium homeostasis on the apoptosis of rat’s primary cul- tured cerebral cortical neurons induced by cadmium,the neurons were exposured to different concentrations of cadmium acetate（0,5,10 and 20 μmol/L ）,in the absence or the presence of 10μmol/L BAPTA-AM for 12 hours. Then, the apoptosis rates, intracellular[Ca2＋ ]i, and reactive oxygen species （ROS）, mitochondrial membrane potential （△ψm） were detected by flow cytometry. In comparison with the control group, the apoptosis rate, intracellular [Ca2＋ ] and ROS level increased significantly（ P〈0.05 or P〈0.01 ） ,△ψm decreased significantly （P〈0.05 or P d0.01） in the cadmium groups. Compared to the poisoning groups, the apoptosis rate, intracelluar[Ca2＋ ], ROS level decreased and △ψm increased in the presence of BAPTA-AM groups, there was significant difference between partial groups （P〈0.05 or P〈0.01）. It was concluded that cadmium can promote the apoptosis of neurons,the disequilib- rium of calcium homeostasis played a vital role in the cadmium-induced apoptosis of cortical neurons and the increasing of ROS level and decreasing of △ψm induced by calcium overloading,may participate in the apoptosis.