ALA-PDT诱导SW480细胞凋亡和胞内Ca^(2+)浓度变化的关系

Relationship between intracellular Ca(2+) and ALA-PDT induced apoptosis in SW480 cells

目的:探讨ALA-PDT诱导人结肠癌细胞SW480凋亡和游离钙浓度变化关系.方法:将SW480细胞分为四组:空白对照组、激光照射照组、ALA组和ALA-PDT组,用DNA片段分析和TUNEL法检测细胞凋亡;用激光共聚焦显微镜观测各组细胞内游离钙离子浓度的变化.结果:ALA-PDT组的人结肠癌细胞在1、2h有大量的DNA片段,TUNEL法显示ALA-PDT组的人结肠癌细胞在PDT后30minAI为25.26±5.04%,PDT后60minAI为50.45%±7.85%,均高于其他3组(AI均<10%,P<0.01);激光共聚焦结果为ALA-PDT组细胞内游离钙离子浓度在20min达高峰(荧光强度:185.40±18.90),与10min(荧光强度:100.00±19.83)相比有显著差异(P<0.01),之后又逐渐下降.结论:细胞内Ca2+浓度的逐渐增加在PDT诱导的细胞凋亡过程中可能起着重要作用.

AIM： To investigate relationship between intracellular Ca^2＋ and apoptosis induced by aminolaevulinic acidphotodynamic therapy （ALA-PDT） in SW480 cells. METHODS： SW480 cells were divided into control, light, ALA and ALA-PDT group. The corresponding treatment was performed in each group. The apoptosis of SW480 cells was detected by DNA fragment assay and TUNEL assay. The changes of intracelluar Ca^2＋ concentration in each group were observed by confocal laser scanning microscopy. RESULTS： DNA ladder formation of apoptotic features was demonstrated 1 and 2 h after ALA-PDT treatment. The apoptosis index （AI） of 30 and 60 min after ALA-PDT treatment was 25.26 ± 5.04% and 50.45 ± 7.85%, respectively, which were significantly higher than those in the other 3 groups （all Al 〈10%, P 〈0.01）. The concentration of intracelluar Ca^2＋ 20 min after ALA-PDT treatment was markedly increased than that at 10 min （fluorescent intensity： 185.40 ± 18.90 vs 100.00 ± 19.83, P 〈0.01）, and then gradually decreased. However, the concentrations of intracelluar Ca^2＋ had no significant changes in the other 3 groups. CONCLUSION： The increases of intracellular Ca^2＋ may play an important role in the ALA-PDT-induced apoptosis in SW480 cells.