Effects of microcystin-LR on apoptosis and expression of apoptosis-related proteins in human bronchial epithelial cells

Objective To observe the effects of microcystin-LR(MC-LR) on apoptosis and expression of apoptosis-related proteins in human bronchial epithelial cells(16HBE). Methods Cell viability was assessed by MTT after treatment by MC-LR with different concentration(0-40 μg/ml) for 24 h. After treatment with MC-LR(0,2.5,5,10 μg/ml) for 24 h and 48 h,rate of apoptosis was measured by Annexin V- FITC and PI combined with flow cytometry. The expression of cytochrome-c(Cyt-c),B-cell lymphoma-2(Bcl-2) and Bcl-2 associated X protein(Bax) were detected with Western blot. Results Cells viability decreased with the increase of MC-LR concentration. Apoptosis rates of 16 HBE cells increased with the increase of MC-LR concentration during a certain exposure period,increased with the increase of MC-LR exposure time at a certain concentration.the relative expression of Cyt-c,Bax in 16 HBE cells increased and the expression of Bcl-2 decreased in the groups of 5 μg/ml and 10 μg/ml MC-LR compared with those of control group with statistical significance(P0.05). Conclusion Microcystin-LR induces apoptosis of 16 HBE,increases the expression of Bax and Cyt-c,and reduce the expression of Bcl-2.