OBJECTIVE:To explore the transfection effects and cell toxicity of mock miRNA at different concen-trations,liposome at different concentrations and different transfection times in human bronchial epithelial cells in vitro and optimize transfection conditions.METHODS:16-HBE cells were incubated with 0,10,30 and 50 nmol/L Cy3 labelled mock miRNA and 0,0.1%,0.3% and 0.5% liposome.The transfection effects in the cells were examined by fluorescence microscopy and were evaluated by fluorescence intensity analysis after 6,12 and 24 h of transfection.Cell activity was measured after 24 h transfection with different transfection conditions by WST-8 method.RESULTS:Intracellular fluorescence intensity was enhanced with increasing mock miRNA and liposome concentration and transfection time.The transfection effects of 30 and 50 nmol/L mock miRNA transfection groups was significantly higher than 10 nmol/L mock miRNA transfection group(P0.05).The transfection effects of 0.3% and 0.5% liposome groups were obviously higher than 0.1% liposome groups(P0.05).Intracellular fluorescence intensity after 24 h transfection was remarkably increased those that after 6 and 12 h transfections(P0.05).There was no significant difference in cell toxicity between transfection groups and control group(P0.05).CONCLUSION:16-HBE cell could be used in the research of liposome-mediated delivery of mock miRNA.Mock miRNA and liposome concentration and transfection time are important influence factors of transfection.Optimal transfection effects could be obtained after 24 h transfection with 30 nmol/L mock miRNA and 0.3% liposome.There was no effect on the cellactivity after transfection.