AIM:To investigate the cobalt chloride(CoCl₂)simulated hypoxic environment's effect on the gene expression and protein secretion of vascular endothelial growth factor(VEGF)of rats' retinal progenitor cells(RPCs).

METHODS: RPCs were separated, cultured and identified by the use of neurospheres-adhesive culture. RT-PCR and ELISA were used to detect the change of RPCs VEGF's expression after 24-hour intervention of CoCl₂ with different concentration(0, 50, 100, 150μmol/L and 200μmol/L), and detect the change of RPCs VEGF's expression in 150μmol/L CoCl₂ for different period(0, 12, 24, 36, 48, 72 hours).

RESULTS: The RPCs cultured by neurospheres-adhesive culture system could highly express the specificity of stem cells(Nestin), and express mature retinal neuron after natural differentiation. After culturing them in the hypoxic environment for the same period, the gene express of VEGF gradually increased and then decreased with the increasing concentration of CoCl₂, and peaked(P≤0.05)when the concentration of CoCl₂ was 150μmol/L. When the concentration of CoCl₂ was 150μmol/L, the gene expression of VEGF also gradually increased and then decreased with the increasing hypoxia intervention period, and peaked(P≤0.05)when the hypoxia intervention period was 36 hours, the change of protein and gene expression were consistent.

CONCLUSION: The RPCs cultured by neurospheres-adhesive culture system can better express the specificity of stem cells. Under CoCl₂ simulated hypoxic environment, hypoxia strengthens RPCs VEGF's secretion and dependent on the time and dose.