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Erschienen in:
01.06.2011 | Basic Science
The contrasting effect of estrogen on mRNA expression of VEGF in bovine retinal vascular endothelial cells under different oxygen conditions
Erschienen in: Graefe's Archive for Clinical and Experimental Ophthalmology | Ausgabe 6/2011
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Objective
To investigate the influence of Estradial (E2) at physiological concentration on mRNA expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α(HIF-α1) in bovine retinal vascular endothelial cells (BRECs) under different oxygen conditions.
Methods
The mRNA expression of VEGF, HIF-1α in BRECs was studied by quantitative reverse-transcription PCR (qRT-PCR), and protein levels were assayed by Western Blot. Different concentrations of E2 (10−12, 10−10, 10−8 mol/l) and estrogen receptor antagonist Tamoxifen (10−7 mol/l) were added into the cell culture medium of different groups, while the phosphate-buffered saline (PBS) was added in the control group instead. Culture conditions were set to be under normoxia and hypoxia. The results of each group were detected after 8 hours and 24 hours.
Results
(1) Under hypoxia, gene expression of VEGF, HIF-1α in BRECs increased more than that of the control group (P < 0.05). There is evident positive correlation between the mRNA and protein levels of VEGF and HIF-1α (r = 0.82). (2) Treated with 10–8 mol/l E2, the expression of VEGF mRNA was increased in a time–dependent manner (P < 0.05). Treated with the indicated to concentrations of E2 (10−
12
∼ − 8 mol/l) under normoxia for twenty-four hours, the mRNA expression of VEGF in BRECs was increased in a dose–dependent manner (P < 0.05), whereas E2 did not influence the mRNA expression of HIF-1α (P > 0.05). (3) Under hypoxia , E2 reduced the mRNA and protein levels of HIF-1α and VEGF in a concentration-dependent manner (P < 0.05), and the decrease developed in a time-dependent manner (P < 0.05). (4) An overdose of tamoxifen (10−7 mol/l) reversed the effect of E2 (10−8 mol/l) (P < 0.05).
Conclusions
E2 increases the gene expression of VEGF in BRECs under normoxia, whereas E2 reduces the gene expression of VEGF in BRECs through HIF-1α under hypoxic conditions in a dose-dependent and time-dependent manner. The contrasting effect of E2 on mRNA expression of VEGF may play a prophylactic role in retinopathy of prematurity (ROP).