Inhibitory effects of ursolic acid on oxygen-induced mouse retinal neovascularization via intravitreal injection.

Objective: This study aimed to explore the effects and mechanisms of ursolic acid (UA) on oxygen-induced retinal neovascularization (RNV) in mice and its inhibitory effects on human retinal capillary endothelial cells (HRCECs) under high-glucose conditions. Methods: Neonatal mice were divided into five groups: one normal group and four with oxygen-induced retinopathy (OIR), including OIR, phosphate-buffered saline, UA and Lucentis groups. On postnatal day 17 (P17), mice were euthanized and one eye was collected for retinal analysis using fluorescence microscopy. Protein and messenger ribonucleic acid (mRNA) levels of vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2, MMP-9 and cyclo-oxygenase-2 (COX-2) were detected. HRCECs cultured under high-glucose conditions were treated with UA to assess its effects on proliferation and molecular expression. Results: UA significantly reduced RNV area in OIR mice and protected astrocytes from hypoxia-induced damage (p<0.01). VEGF, MMP-2, MMP-9 and COX-2 levels were lower in the UA group compared with the OIR and phosphate-buffered saline groups (p<0.05), but slightly higher than in normal controls (p<0.01). Lucentis reduced VEGF levels but did not significantly affect MMP-2, MMP-9 or COX-2. In HRCECs, UA inhibited high-glucose-induced proliferation and reduced VEGF, MMP-2, MMP-9 and COX-2 expression in a time- and dose-dependent manner. Conclusions: UA inhibits RNV by reducing VEGF, MMP-2, MMP-9 and COX-2 expression, protecting astrocytes and suppressing HRCEC proliferation under high-glucose conditions, highlighting its therapeutic potential for retinal neovascular diseases.