Establishment of a cellular model of hypoxic acclimatization in human HepG2 cells

AIM: To establish a cellular model of hypoxic acclimatization using HepG2 cells to explore the mechanism of cellular hypoxia acclimatization. METHODS: HepG2 cells were cultured in 1% O_2 for 24 hours, then in 21% O_2 for another 24 hours,which composed a hypoxic treating cycle. After 6 cycles, the activity of cell proliferation was estimated with MTT method. The morphologic features of HepG2 cells were observed with optical microscope and transmission electron microscope. EPO gene expression was detected by Northern blotting technique. RESULTS: Acute hypoxia inhibited cellular mitosis, impaired cellular ultrastructure and induced EPO gene expression. After 6 cycles of hypoxic treatment, proliferation ability of HepG2 treated with acute hypoxia for 48 h was resumed to the level of control cells cultured in 21% O_2. The ultrastructure of HepG2 cells injured by hypoxia recovered and the level of EPO gene expression returned to that in control cells. CONCLUSION: After 6 cycles of hypoxic treatment, the ability of HepG2 to endure hypoxia is obviously enhanced and HepG2 cells might reach the status of hypoxic acclimatization.