Inhibitory Effect of Alpha-Crystallins on VEGF-Induced Proliferation of Retinal Microvascular Endothelial Cells

Purpose: Lens extraction surgery with ischemic retinopathy may trigger neovascularization, suggesting that lens removal alters the ocular concentrations of angiogenesis regulatory factors. This study aims to identify angiogenic or anti-angiogenic factors exhibiting altered expression in the vitreous after lens extraction in rabbits. Methods: Vitreous samples after lens extraction were analyzed by two dimensional fluorescence difference gel electrophoresis (2D-DIGE) followed by mass spectrometry to identify candidate factors indicating expression changes. Western blotting and real-time polymerase chain reaction (PCR) were performed to semi-quantify protein and gene expression changes. The identified factors were tested by assessing effects on vascular endothelial growth factor (VEGF)-induced proliferation of human retinal microvascular endothelial cells (HRMECs). Results: Three spots with reduced expression were identified as αA-crystallin by 2D-DIGE and mass spectrometry. Western blotting revealed that the protein levels in vitreous of αA- and αB-crystallin were significantly lower after lens extraction. αB-crystallin suppressed the proliferation of VEGF-stimulated HRMECs, and the combination of αA- and αB-crystallin was more effective than αB-crystallin alone. Conclusion: The depletion of vitreal α-crystallins after lens extraction may increase VEGF-induced angiogenesis, thereby contributing to adverse outcomes such as vitreous hemorrhage, proliferative membrane, and vision loss after cataract surgery for ischemic retinopathy patients.