大肠杆菌感染对人巨噬细胞系U937凋亡的影响

Effect of Escherichia coli infection on cell apoptosis of human macrophage cell line U937

目的探讨大肠杆菌(E.coli)感染与人巨噬细胞系U937细胞凋亡的关系。方法以AnnexinVFITC/PI双染流式细胞仪检测及Hoechst33258荧光染色,Giemsa染色等细胞形态学观察为指标,研究E.coli感染对U937细胞凋亡的诱导作用。结果Giemsa染色E.coli感染10,20min(U937E.coli=1∶20)后偶见细胞凋亡,感染30,60及90min时可见许多细胞有典型的凋亡形态学改变,并可见凋亡小体;AnnexinVFITC/PI双染可见U937细胞凋亡百分率随E.coli感染时间的延长而增高。感染30,60及90min时,细胞凋亡率与对照组相比明显增高,有显著性差异(P<0.001)。Hoechst33258荧光染色结果表明当细胞与细菌浓度比较低时(1∶10)即可引起部分U937细胞发生凋亡,U937细胞凋亡百分率随E.coli感染剂量的增加而增加,且Hoechst33258荧光染色及流式细胞仪二种方法所得结果一致。结论E.coli以时间和剂量依赖方式诱导U937细胞凋亡。

Objective： To study the relationship between Escherichia coli （ E. coli ） infection and cell apoptosis of human macrophage cell line U937. Methods： The U937 apoptosis induced by E. coli infection was detected with Annexin V FITC/PI assay, Hoechst 33258 fluorochrome staining, and Giemsa staining. Results： Giemsa staining showed that few apoptotic U937 cells were found 10 and 20 minutes after E. coli infection （ U937 ： E. coli = 1 ： 20） , and U937 cells underwent typical apoptotic changes including karyopyknosis, condensation, swelling, and apoptotic bodies 30, 60 and 90 minutes later. Annexin V FITC/PI assay showed that the percentage of apoptotic U937 cells increased with the progression of the E. coli infection. Hoechst 33258 fluorochrome staining and Annexin VFITC/PI assay showed that the percentage of apoptotic U937 ceils increased with the concentrations of E. coli. Conclusion： E. coli could induce U937 apoptosis in a dose-and time-dependent manner.