[Effect of integrin α9β1 on corneal neovascularization and vascular endothelial growth factor A expression after corneal suture in rats].

OBJECTIVE: To investigate the effect of integrin α9β1 on corneal angiogenesis and the expression of vascular endothelial growth factor A (VEGF-A) in rats after corneal suture. METHODS: Thirty-nine SD rats were randomly divided into normal control group, corneal suture model group, α9β1 group, and α9β1 suppression group, and in the latter 3 groups, the rats received topical administration of levofloxacin, levofloxacin + α9β1, and levofloxacin+ anti-α9β1 monoclonal antibody (Y9A2) twice daily after corneal suture, respectively. At 3, 5, 7, 14 days after the surgery, 3 rats were randomly selected from each group to observe corneal neovascularization (CNV) under slit lamp. RT-PCR and Western blotting were used to detect the expressions of VEGF-A. RESULTS: CNV was not observed in normal cornea. Neovascularization occurred in the corneal limbus in the 3 corneal suture groups, and the leak neovascularization count (CNVC), which occurred on the 7th postoperative day, was significantly increased after α9β1 treatment compared with that in the model group (4.57∓0.31 vs 3.21∓0.19, P<0.05) but markedly decreased after α9β1 suppression (2.03∓0.26, P<0.05). VEGF-A was expressed at a low level in normal cornea, and increased significantly in the model group, reaching the peak level on 7th day (P<0.05); corneal VEGF-A expression was further enhanced by α9β1 treatment (P<0.05) while significantly lowered by α9β1 suppression (P<0.05). CONCLUSION: Integrin α9β1 can promote CNV by up-regulating VEGF-A expression and α9β1 suppression produces the opposite effect after corneal suture in rats.