胆红素诱导神经细胞凋亡及对其线粒体膜电位的影响——胆红素对中枢神经细胞损伤机理的研究

Bilirubin induced apoptosis of human neuroblastoma cell line SH-SY5Y and affected the mitochondrial membrane potential

目的 观察胆红素诱导人神经母细胞瘤SH SY5Y细胞凋亡及对其线粒体膜电位(mitochondrialmembranepotential,MMP)的影响 ,探讨高胆红素血症对中枢神经细胞损伤的分子机制及在听神经病发病中的作用。方法 将胆红素 (0 0 2g/L)直接作用于体外培养的SH SY5Y细胞 ,在不同时间点通过倒置显微镜观察细胞形态的变化及存活情况 ;经Hoechst332 5 8染色后 ,在荧光显微镜下观察细胞核的形态变化 ;利用流式细胞仪检测细胞的凋亡率 ;经罗丹明 12 3染色后 ,用流式细胞仪检测线粒体膜电位的变化。结果 在 0 0 2g/L胆红素作用下 ,SH SY5Y细胞 2h后即可见较多细胞皱缩、变圆 ,4h可见有少数细胞飘起 ,细胞轮廓不清 ,6h可见大部分细胞飘起 ,并已开始崩解 ;染色质在胆红素作用 6h出现典型的凋亡样改变 ;细胞凋亡率随作用时间的延长明显增加 ,3h为 19 4 % ,4h为 76 4 % ,6h达到 79 0 % ;在胆红素作用 1h后反映线粒体膜电位相对荧光强度即由 (16 6± 1 5 5 6 )U下降到 (7 11± 0 70 1)U ,差异有显著性 (P <0 0 1) ,并随作用时间的延长而进一步降低。结论 胆红素作用早期即可导致SH SY5Y细胞线粒体膜电位下降 ,既而发生凋亡 ,提示通过诱导听觉中枢神经元凋亡可能在高胆红素血症所致的听力损伤和听神经病发病中起重要作?

Objective To study whether bilirubin induces apoptosis of human neuroblastoma cell line SH SY5Y and affects the mitochondrial membrane potential Methods SH SY5Y cells were exposed to bilirubin, then morphological changes of nucleus were assayed by Hoechst 33258 staining The percentage of apoptotic cells was measured by flow cytometry The mitochondrial membrance potential(MMP) was detected by flow cytometry through Rhodamine123 staining Results MMP of SH SY5Y cells significantly decreased from (16 6±1 556)U to (7 11±0 701)U ( P <0 01) after exposed to 0 02 g/L bilirubin for 1 h The percentage of apoptotic cells was 19 4% after exposed for 3 h,and significantly increased to 76 4% after 4 h, but typical apoptotic nuclear changes occured after 6 h Conclusion Bilirubin could early cause disruption of MMP, then induce the apoptosis of SH SY5Y cells