[Experimental study of (Pro)renin receptor siRNA inhibiting retinal neovascularization]

To observe the inhibit effect of (pro)renin receptor siRNA on mice retinal neovascularization, and investigate its possible mechanism.

Experimental study. 72 new born C57BL/6J mouse were randomly divided into six groups: group A to group E were exposed to hyperoxia, and then returned to normoxia to induce retinal neovascularization. Group A were treated with PRR siRNA plasmid, group B with control plasmid, group C with PRR siRNA and Losartan, and group D with Losartan. Group E were not treated. Group F was control group. Mouse were sacrificed at postnatal day 17, retinal perfusion stretched preparation and HE dyeing method were used to observe the status of retinal neovascularization. PRR expression and the activation of extracellular regulated protein kinases 1/2 (ERK1/2) were detected by Western Blot. And Real Time PCR was used to detect the expression of transforming growth factor-β1 (TGF-β1) in group A, B, E and F. Analysis of one way variance (LSD) was used and statistical difference was considered significant at a P value less than 0.05.

The mouse treated with PRR siRNA, Losartan and combined therapy could significantly reduce retina neovascularization and vessel leakage compared with oxygen-induced retinopathy group and control plasmid group. Average counts of vascular endothelial cells which break through the inner limiting membrane performed at postnatal day 17 in PRR siRNA group (4.47 ± 1.96), Losartan group (5.94 ± 2.54) and combined therapy group (4.49 ± 2.53) were significantly lower than oxygen-induced retinopathy group (32.73 ± 6.38) (P < 0.05) and control plasmid group (21.04 ± 5.39). Western Blot showed that PRR protein express in hyperoxia induced group was significantly higher than normal (P = 0.007). After treated with PRR siRNA or combined therapy, the expression of PRR protein was significantly lower than hyperoxia induced group (P < 0.05). There are no significantly differences between control plasmid group, Losartan group and hyperoxia induced group (P > 0.05). The activated ERK1/2 lever in hyperoxia group was significantly higher than normal (P = 0.003). After treated with PRRsiRNA, Losartan or combined therapy, activated ERK1/2 lever was significantly lower than hyperoxia induced group (P < 0.05). And the effect of PRR siRNA group and combined therapy group seems more obviously, compared with Losartan group, the difference was significantly (P < 0.05). Real Time PCR showed that the lever of TGF-β1 in hyperoxia group was significantly higher than normal (P = 0.001). After treated with PRR siRNA, the TGF-β1 was significantly reduced (P = 0.004), and there was no significantly difference between control plasma group and hyperoxia induced group (P = 0.222).

PRR combined with prorenin or renin could activate ERK1/2 signal transduction passageway, and promote cell proliferation, differentiation and migration, thus promote retinal neovascularization. PRR siRNA could obviously reduce PRR expression, inhibit ERK1/2 signal transduction passageway activation, and diminish retinal neovascularization.