AIM: To investigate the effect of hypoxia on the expression of NOX4 in cultured human RPE cells in vitro.

METHODS:Human RPE cells were cultured and passaged, and 3-6 generation cells were used in the experiment. The experiment was divided into normoxia control group and hypoxia group. The human RPE cells in normoxia control group were routinely cultured. The culture medium containing 200μmol/L CoCl₂ was used to establish the hypoxia model of human RPE cells cultured in vitro for 0,4,6,8,12 and 24h, and the RPE cells cultured normoxia were as controls. The effects of different time of hypoxia on the expression of NOX4 were identified by Immunofluorescence staining and Western-blot assay.

RESULTS:RPE cells grew well in the control group and hypoxia group. The morphology was spindle. The morphology and arrangement of cells in hypoxia group had no significant change compared with the control group. Immunofluorescence staining showed that there was a small amount of NOX4 expression in the RPE cells of the normoxia control group. Cytoplasm showed green fluorescence while the nucleus was blue. The expression of NOX4 increased after hypoxia, and continued until the late stage of hypoxia. Western-bolt results showed that the expression level of NOX4 under hypoxic conditions in RPE cells increased significantly, and is proportional to the hypoxia time, the difference was statistically significant(P<0.05).

CONCLUSION: NADPH oxidase 4 in normal human RPE cells have a small amount of expression, hypoxia can significantly increase the expression of NOX4, and is proportional to the time. It suggests that NADPH oxidase may play an important role in the formation of choroidal neovascularization.