Role of hypoxia-inducible factor 1α on corneal neovascularization after alkali burn in rabbits

Abstract

Objective To observe the expression of hypoxia-inducible factor 1α(HIF-1α) on corneal neovascularization at different periods after alkali burn in rabbits, and to investigate the effect of HIF-1α on corneal neovascularization. Methods Experimental study. One mol/L NaOH was used to establish a corneal alkali burn model on the right eyes of 30 healthy rabbits (left eyes were the controls). The rabbits were randomly divided into 5 groups, 6 rabbits in each group. Corneal neovascularization (CNV) of rabbit morphology with HE staining was observed before alkali burn and 1, 3, 5, 7, and 14 days after burn. Meanwhile, the expression of inflammatory cells (polymorphonuclear leukocyte and lymphocyte) and HIF-1α on corneal tissues was tested with an immunohistochemical method and quantified by counting the positive nuclei, and analyzed with a One-Way analysis of variance and correlation analysis. Results The protein of HIF-1α was expressed in inflammatory cells and neovascular endothelial cells of corneal stroma. The expression of HIF-1α gradually increased with the expression of inflammatory cells, peaked on the 5th day, then decreased with time. Inflammatory cells and HIF-1α levels in each group at 1, 3, 5, 7, and 14days after alkali burn were statistically different (F=422.286, 437.555; P＜0.05 for both). Positive correlations were found between inflammatory cells and HIF-1α positive cells by correlation analysis (r=0.860, P＜0.05). The expression of HIF-1α was parallel to the formtion of new blood vessels in the cornea. Conclusion Inflammation can induce the expression of HIF-1α after alkali burn. The expression of HIF-Iα can promote the corneal neovascularization. Key words: Corneal neovascularization; Hypoxia-inducible factor 1α; Cornea; Burns,alkali; Disease models,animal