ABSTRACT
Objective To study the morphology and the effect of bovine lactoferricin (LfcinB) for Jurkat T leukemia cells and HFL-I cell and further validate and analyze the signal transduction passage way of LfcinB-induced apoptosis. Method The Jurkat T leukemia cells and fibroblasts stained with Hoechst 33258 after in vitro treatment with LfcinB were observed through fluorescence microscope, compared with positive and negative control groups to analyze the difference between the effect of LfcinB on Jurkat T leukemia cells and HFL-I cell with gel electrophoresis analysis of DNA fragmentation. Early apoptosis and mitochondrial membrane potential of Jurkat T leukemia cells were analyzed by flow cytometry, and the changes of caspase-3, caspase-8, caspase-9 and cytochrome C in endochylema of Jurkat T leukemia cells after exposed to LfcinB during 4, 6 and 8 h were detected by Western blotting. Results DNA Ladder was shown by gel electrophoresis analysis of DNA fragmentation in Jurkat T leukemia cells following treatment with LfcinB, which was not found in HFL-I cell. Through fluorescence microscope, we found that nucleus of LfcinB-exposed Jurkat T leukemia cells stained with Hoechst 3325 became condense, but the nucleus of HFL-I cell was not changed. The results of flow cytometry analysis indicated that apoptosis rates of Jurkat T leukemia cells exposed to LfcinB for 2, 4 h were 11.5% and 17.8% respectively, with decline of mitochondria membrane potential. Immunoblot analysis showed that LfcinB could increase the content of cytochrome C, with the activated caspase-3 and caspase-9 increase gradually in endochylema of Jurkat T leukemia cells, however there was no effect of LfcinB on caspase-8. Conclusion LfcinB induced apoptosis of Jurkat T lenkemia cells, but not affected fibroblasts. After Jurkat T leukemia cells, contacted with LfcinB for more than 2 h, the contents of caspase-3, caspase-9 and cytochrome C in the cells were cumulatively increasing, which further validated that LfcinB induced Jurkat apoptosis by intra-cellular signal pathway depending on caspase family.