GPER-mediated inhibition of astrocyte activation mitigates retinal neovascularization in oxygen-induced retinopathy mice

Abstract

Objective To investigate the mechanism by which G protein-coupled estrogen receptor (GPER) reduces retinal neovascularisation in oxygen-induced retinopathy (OIR) in newborn mice. Methods A total of 42 newborn mice were randomly divided into normoxic control group (n=11), OIR group (n=11), G-1(GPER agonist) group (n=10), and solvent control group (n=10).On postnatal day 17(P17), the distribution of GPER in the retina of mice in the normoxic control group was observed by immunofluorescence staining on frozen sections of the eyeballs.The mice of the G-1 group and solvent control group were given by intraperitoneal injection 50 μg/(kg·d) G-1 or corn oil solvent from P12 to P15.Immunofluorescence staining of retinal spreads at P17 was performed to observe the expression of retinal vascular marker IB4 and astrocyte marker glia fibrilary acidic protein (GFAP).Western blotting was used to quantify the expression of retinal vascular endothelial growth factor A (VEGFA), GFAP, and inflammatory factors TNF-α, IGF-1, and IL1-β. Results GPER was present throughout the retina and co-stained with the astrocyte marker GFAP in the ganglion cell layer (GCL).Compared with the normoxic control group, the retinas of mice in the OIR group showed neovascular and avascular areas, and the expression of VEGFA and GFAP was significantly increased (P < 0.05).Compared with the solvent control group, the retinal neovascularisation was reduced in the G-1 group, and the expression levels of VEGFA, GFAP, TNF-α, IGF-1, and IL1-β proteins were decreased significantly (P < 0.05). Conclusion GPER inhibits astrocyte activity, reduces VEGFA expression and release of inflammatory factors, and then decreases retinal neovascularisation in OIR mice.

Keywords

• retinopathy of prematurity
• newborn mouse model of oxygen-induced retinopathy
• astrocytes
• inflammatory factors
• g protein-coupled estrogen receptor