慢性高眼压状态下水通道蛋白-1在家兔角膜内皮细胞的表达变化

Expression of aquaporin-1 in rabbit corneal endothelium after chronic ocular hypertension

目的观察慢性高眼压状态下水通道蛋白-1(AQP-1)在家兔角膜内皮细胞上的表达变化。方法 30只成年家兔随机分为对照组,2、3、4、5周组。非对照组实验兔左眼前房内注入质量分数0.3%卡波姆和质量分数0.025%地塞米松的复方卡波姆溶液0.2 mL,眼压达22 mmHg以上者为制作家兔慢性高眼压模型成功;对照组左眼用同样方法注入平衡盐液0.2 mL。建模后每日测量眼压1次,裂隙灯下观察实验眼结膜、角膜及虹膜组织的反应。注药后2、3、4、5周分别处死各组实验兔并制作角膜标本,应用免疫组织化学法检测角膜内皮中AQP-1蛋白的表达,应用半定量逆转录聚合酶链反应(RT-PCR)法检测家兔角膜内皮中AQP-1 mRNA在角膜内皮中的表达。所有动物的饲养及处死遵循NIH的《实验动物管理及使用指南》。结果建模后实验动物的眼压呈缓慢升高的趋势,3周时达到最高,之后眼压逐渐下降,5周时眼压接近正常。在建模后18～24 d,角膜水肿和虹膜组织炎症反应最严重。AQP-1在正常和高眼压家兔的角膜内皮均有表达,各组间AQP-1的吸光度(A)值差异有统计学意义(F=3.650,P=0.018),AQP-1 mRNA在角膜内皮中的表达量亦随之出现先升高后降低的趋势,各组的总体比较差异有统计学意义(F=4.140,P=0.000)。AQP-1在角膜内皮中的表达量在造模后2、3、4、5周时与对照组间差异均有统计学意义(P<0.05)。结论 AQP-1可能在家兔角膜内皮损伤修复过程中起到重要作用。

Background Expression of AQP-1 protein appears during the embryonic period.The level of AQP-1 mRNA synthesis is gradually declined after born.However,the expression level of AQP-1 protein after born remains near to embryonic period.AQP-1 is very important for the restoration of corneal endothelium following injury.ObjectiveThe purpose of this experimental study was to investigate the expression of aquaporin-1（AQP-1） in cornea tissue after chronic experimental elevation of intraocular pressure（IOP）.MethodsThe chronic ocular hypertension models were established in 24 eyes of 24 domestic rabbits by injecting 0.2mL compound carbomer solution（0.3% carbomer and 0.025% dexamethasone） into the anterior chamber to elevate the IOP to 22mmHg or over.The same amount of normal solution was used at the same way in other 6 rabbits as control group.IOP,conjunctiva,cornea and iris of the animals were examined under the slit lamp once a day after injection of the anterior chamber.These animals were sacrificed in 2,3,4,5 weeks after injection respectively and the left eyes were enucleated.The expressions of AQP-1 protein and mRNA in cornea of rabbit were detected using immunohistochemistry（A value） and semi-quantitative reverse transcription polymerase chain reaction（RT-PCR） respectively.The use of experimental animals followed the Guide for the Care and Use of Laboratory Animals by NIH（USA）.ResultsThe IOP of rabbits was significantly elevated after injection of the anterior chamber from 2 weeks through 5 weeks with the highest IOP in the third weeks.Edema of corneal tissue and the inflammation response of iri were most serious in 18-24 days after injection.AQP-1 protein was positively expressed in cellular membrane and cytoplasm of corneal endothelium with the strongest expression in 3 weeks after IOP elevated.The A value of AQP-1 protein was lowest in control eyes but enhanced in model eyes with the highest A value in the models of 3 weeks group.Statistically significant differences were found in the A value of AQP-1 among 2,3,4,5 weeks groups and control group（F=3.650,P=0.018）.The expression of AQP-1 mRNA in corneal tissue in different time durations followed the same pattern to AQP-1 protein（F=4.140,P=0.000）.ConclusionAQP-1 may be involved in the damage and restoration of corneal endothelium in chronic high IOP rabbit.