[The effect of vascular endothelial growth factor and hypoxia on the secretion of opticin in retinal pigment epithelium cells].

ABSTRACT

OBJECTIVE: To evaluate the role of vascular endothelial growth factor or hypoxia on the secretion of opticin in retinal pigment epithelium cells. METHODS: Human RPE cells were cultured, the third to sixth passage of retinal pigment epithelium (RPE) cells were placed in 6-well culture plates at a density of 4 × 10(4)/well. For hypoxia experiment, the cells were cultured under hypoxic condition for different times. For vascular endothelial growth factor (VEGF) experiment, the media was changed to DMEM containing different concentration VEGF (1, 10, 50, 100 µg/L) for 24 h respectively. VEGF mRNA levels were determined by RT-RCR method. The protein content of opticin in RPE cells or culture media was detected by Western blot. Matrix metalloproteinase activity in culture media was analysis by zymography. One way ANOVA was used to test the comparisons between experimental groups and control group. RESULTS: Western blot experiment showed the opticin expression was not changed in RPE cells after hypoxia treatment, however was significantly decreased in culture media. Compared with control group (0.21 ± 0.03). The relative density of VEGF mRNA levels (0.81 ± 0.04, 0.67 ± 0.07) in RPE cells were increased after 12 h or 24 h hypoxia treatment (F = 483.60, P < 0.05). Opticin expression in RPE cells was also remain unchanged after vary concentration VEGF addition treatment (F = 2.16, P > 0.05), the relative density of opticin expression in VEGF conditioned culture medium were 0.65 ± 0.02, 0.52 ± 0.04, 0.23 ± 0.03, 0.30 ± 0.03 respectively, and the difference in culture media was significant compared to control group (0.73 ± 0.04) (F = 141.38, P < 0.05). Zymography indicate a matrix metalloproteinases type 2 digest band, the activities were enhanced with VEGF increasing. The decrease of opticin in culture media after VEGF treatment could be inhibited by low condition of EDTA. CONCLUSION: VEGF and hypoxia have an effect on the on the secretion of opiticin in RPE cells, it may be contributed to the increasing levels of matrix metalloproteinases type 2.