Expression of AQP-1 in rat cornea neovascularization after alkali burn / 眼科研究

ABSTRACT

Background Corneal alkali burn is a common cause of corneal neovascularization(CNV).Researches demonstrated that aquaporin 1(AQP1) plays key role in neovascularization of tumor tissue.So it is speculated that AQP1 participates in pathogenesis and development of CNV.ObjectivePresent study aims to investigate the expression of aquaporin 1(AQP1) in cornea after alkali burn and explore its role in corneal neovascularization.MethodsCornea neovascularization (CNV) models were established by putting a filter paper (the size of 3 mm in diameter immersed 1mol/L NaOH solution) on cornea for 20 seconds in the left eyes of 25 adult Sprague Dawley rats.The fellow eyes were treated using the filter paper with normal saline solution as normal control group.Corneal new blood vessel was evaluated under the slim lamp biomicroscopy once per day,and area of new vessel was calculated.The animals were sacrificed and corneal samples were obtained in day 1,4,7,14,21 after corneal alkali burn.The expression of AQP1 and VEGF in corneas were detected by immunochemistry,and the relative expression level of AQP1 mRNA in rat cornea was determined using RT-PCR.ResultsThe corneal neovascularization grew at the second day and reached the largest area at the fourteenth day after corneal alkali burn.The expression of VEGF protein (gray value) in corneal sample was significantly elevated from the first day through the fourteenth day after corneal alkali burn in comparison with control group(t_(1d)=12.410,t_(4d)=29.428,t_(7d)=16.030,t_(14d)=13.321,P＜0.05),and then the expression level declined till twenty-one day without obvious difference in comparison with control group(t_(21d)=1.587,P＞0.05).The expression of AQP1 protein showed the same tendency with that of VEGF protein(t_(1d)=7.623,t_(4d)=15.293,t_(7d)=18.291,t_(14d)=14.483,t_(21d)=6.381,P＜0.05).The dynamic change expressions of AQP1 and VEGF showed a significant positive correlation(r=0.834,P＜0.05).The expression of AQP1 mRNA (A value)was weaker in control group but considerably increased after alkali burn with the peak value in the seventh day,showing a significantly difference between day 1,4,7,14 and control group(t_(1d)=3.491,t_(4d)=10.690,t_(7d)=12.936,t_(14d)=10.767,t_(21d)=8.594,P＜0.05).ConclusionThe level of AQP1 expression is markedly related to inflammatory CNV in rat cornea after alkali burn.