兔眼前段缺血诱发虹膜新生血管的研究

Induction of experimental iri neovascularization by ocular anterior segment ischemia in rabbit

目的建立兔虹膜新生血管(NVI)模型,检测房水中血管内皮生长因子(VEGF)的质量浓度。方法5只有色家兔任一眼切断上下内外4条直肌,另一眼作为对照,术后每日在裂隙灯显微镜下观察眼前段炎症反应及新生血管形成情况;术后7d眼前段血管荧光造影观察荧光素渗漏情况。ELISA法测定术前对照眼和术眼术后4、7、11、14d房水中VEGF的质量浓度。结果术后1d实验眼全结膜充血,房水略混浊;术后3d房水混浊,可见尘样KP,虹膜表面开始出现新生血管;第7d所有实验眼虹膜表面均可见新生血管,耳缘静脉注射10%荧光素钠后实验眼房水变绿,30s后荧光激发眼前段血管荧光造影显示明显的高荧光素渗漏,术后第4d,房水中的VEGF质量浓度升高,第7d达高峰,第14d时较对照眼低。结论切断兔上下内外4条直肌引起眼前段缺血综合征,能够有效地诱发NVI的形成;房水中VEGF质量浓度随着新生血管的形成先增高后降低,2周时低于正常水平。

Objective It is important to research the new vessels glaucoma by use of iri neovascularization model. This study was to establish a kind of experimental iri neovascularization model in rabbit. Methods The model of iri new blood vessel was established in 5 pigmented rabbits by cutting down four extraocular rectus muscles from lateral eyes and suturing them on the conjunctiva to induce the ischemla of ocular anterior segment, and the normal fellow eyes were as contrasts. The inflammatory reaction and new vessels were observed by slit-lamp everyday, and on the 7th day, fluorescence angiography of ocular anterior segment was performed by injection of 10% fluorescein sodium to observe the leakage of new vessels on the iris. Level of vascular endothelial growth factor（VEGF） in aqueous humor was detected before and 4,7,11 and 14 days after operation by the ELISA. Results After operation,the conjunctiva showed congestion and aqueous fluid was unclear in the model eyes. On the 3rd day after operation,the KP and cellulose exudation were seen under the slit-lamp, and new vessels were found on the iris of operative eyes and peaked on the 7th day. The green fluorescence was seen in qucous fluid immediately after injection of fluorescence, and fluorescence leakage was presented on the iris 30 seconds later. No similar change occurred in the contrast eyes. The VEGF level in aqueous humor was significantly increased on the 4th day and peaked on the 7tb day and then decreased gradually on the 1 l th day after operation（ t = 4.25,7.85,16.22 ,P 〈 0. 05 ）. On the 14th day, the VEGF level in aqueous humor was lower in model eyes than the contrast eyes（ t = 8.99,P 〈 0.01 ）. Conclusion This model can results in the ischemia of ocular anterior segment and induces the experimental neovascular effectively, and dynamic change of VEGF content in aqueous fluid shows a similar procedure to iri neovascularization.