AIM:To observe the expression of discoidin domain receptor 2(DDR2)in retinal pigment epithelium(RPE)cells under hypoxia state, the expression of DDR2, hypoxia inducible factor-1α(HIF-1α)and vascular endothelial growth factor(VEGF)in RPE cells under hypoxia state with stimulation of collagenⅠ, discussing the effects of collagenⅠ and DDR2 in choroidal neovascularization(CNV).

METHODS:It was an controlled experimental study, using 200μmol/L CoCl₂ treated RPE cells to establish chemical hypoxia model. The expression of DDR2 in cells was examined after hypoxia 0, 2, 6, 12, 24 hours by immunofluorescence, reverse transcription polymerase chain reaction(RT-PCR)and Western blotting. In hypoxia state with collagenⅠ's(10μg/mL in 50 degrees incubated box )stimulation, the expression of DDR2 and HIF-1α in cells were examined after hypoxia 0, 2, 6, 12, 24 hours by RT-PCR and Western blotting, using enzyme linked immunosorbent assay(ELISA)to observe the expression of VEGF in cell culture supernatant.

RESULTS:After prolonged hypoxia, the expression of DDR2 mRNA and protein were reduced. CollagenⅠcould multiply the expression of DDR2 mRNA and protein in hypoxia as time goes on, it could active DDR2. The expression of HIF-1α mRNA, protein and VEGF protein dropped off in hypoxia state with collagenⅠ's stimulation compared with hypoxia.

CONCLUSION: The expression of DDR2 in RPE cells reduced with time under hypoxia state. CollagenⅠcan activate DDR2 as time goes on. In hypoxia state with collagenⅠ's stimulation can surpress hypoxia induced up- regulation expression of HIF-1α and VEGF in RPE cells.