89Sr诱发K562癌细胞凋亡及其相关基因表达研究

目的 探讨^89Sr诱发K562癌细胞凋亡放射毒理效应的分子机理。方法 采用分子病理和定量病理技术研究^89Sr内照射诱导的K562癌细胞凋亡，剂量效应关系和重要相关基因bcl-和bax在其中的表达。结果 K562细胞经^89Sr内照射6和24h，提取DNA，琼脂糖凝胶电泳图谱上出现典型的“阶梯状”区带，伴有“拖尾”，而对照组未见“阶梯状”区带，荧光双标记流式细胞仪法定量检测，^89Sr内照射6，9，12，24和48h后，K562细胞凋亡率和坏死率均较对照组有明显升高（P＜0．01），随着^89Sr内照射时间的延长，累积剂量的提高，均无显著变化（P＞0．05），免疫组织化学染色显示，对照组K562细胞中bcl-2和bax蛋白均有表达，bcl-2蛋白表达阳性细胞率82．8％，bax为44.4%,bcl-2/bax比值1.86;^89Sr内照射24h后的K562细胞中，bcl-2蛋白表达阳性细胞率31.4%,bax为38.2%,bcl-2/bax比值0.82，与对照组相比，差异显著（P＜0．05）；RT－PCR显示bcl-2 mRNA在对照组K56细胞中高表达；^89Sr内照射12h后已有明显的下调，24h后则非常显著。结论 ^89Sr内照射K562细胞后，细胞凋亡与细胞坏死并存，且^89Sr诱导K5622细胞的凋亡可能是通过bcl-2 mRNA及其蛋白表达降低，bcl-2/bax比值下降而调控的。

The apoptosis and expression of Bcl-2 mRNA,Bcl-2 and Bax of K562 cells following internal exposure to strontium-89

Objective To explore the characteristics and mechanism of apoptosis in K562 cells induced by radianuclides strontium-89. Methods Using molecular and quantitative pathological technique,the apoptosis and expressions of bcl-2 mRNA,bcl-2 and bax protein of K562 cells following internal exposure to strontium-89 were studied. Results At 6 hrs after irradiation,the characteristic featares of apoptosis and necrosis appeared in K562 cells.The apoptosis and necrosis were enhanced with the prolongation of internal contamination time from 6,9,12,24 to 48 hrs.The expression of bcl-2 mRNA decreased at 12 hrs,most remarkably at 24 hrs,The expression of bcl-2 protein decreased after irradiation whereas bax protein did not change obviously. Conclusion The results suggest that apoptosis induced by internal exposure may be regulated by reducing expressions of bcl-2 mRNA,bcl-2 protein,and lowering bcl-2/bax ratio. ;