玻璃体内注射塞来昔布对激光诱导大鼠脉络膜新生血管的抑制作用

Inhibiting effect of celecoxib intravitreal injection on choroidal neovascularization in a rat model

目的观察选择性环氧化酶-2(COX-2)抑制剂塞来昔布对实验性大鼠脉络膜新生血管(CNV)的影响及其机制。方法雄性棕色挪威大鼠36只,以右眼为实验眼,激光光凝诱导实验性CNV模型。模型建立成功后,36只大鼠立即随机分为治疗组(n=18)和对照组(n=18),分别玻璃体内注射10μL塞来昔布(1mg/mL)和10μL生理盐水。光凝后7d采用Westernblot(n=6)和RT-PCR(n=6)分别检测血管内皮生长因子(VEGF)蛋白及其mRNA以及COX-2mRNA的表达;光凝后14d采用苏木精-伊红染色(n=3)和脉络膜铺片(n=3)法分别检测CNV的厚度和面积。结果经塞来昔布治疗后,CNV的厚度和面积均明显减小(P=0.00),VEGF蛋白及其mRNA表达均明显下降(P=0.02,P=0.03),而COX-2mRNA无明显变化(P=0.59)。结论玻璃体内注射塞来昔布能够有效地抑制实验性CNV,其可能是通过抑制VEGF的表达而发挥作用的,为临床防治CNV相关性眼病提供新思路。

Objective Our previous study showed that cycloxygenase-2 （COX-2） and vascular endothelial growth factor （VEGF） are expressed in choroidal neovascularization （CNV） and the expression of COX-2 is prior to VEGF, indicating that COX-2 is probably one of upstream regulatory factors of VEGF. The aim of this study was to observe inhibition and mechanism of intravitreous injection of celeeoxib, a selective COX-2 inhibitor, on experimental choroidal neovaseularization in a laser-induced rat model. Methods Retinal photocoagulation was performed in 36 right eyes of 36 male Brown Norway rats to establish CNV models with the laser parameter as follows：wavelength 532 nm, power 80 roW, spot diameter 100 pLm and time shutter 100 ms. Eight or ten spots were irradiated in the position of 1.5 - 2.0 PD to optic disc. Celecoxib or normal saline solution was intravitreously injected via scleral incision in 18 right eyes of 18 rats,respectively. The thickness and area of CNV were qualified by HE staining（n = 3 ） and by choroidal flatmount （ n = 3 ） at day 14 after photoeoagulation under the light microscope. The expressions of VEGF and COX-2 in RPE-choroid-sclera complex were examined by Western blot（ n = 6） and RT-PCR（ n = 6） at day 7 after photocoagulation. The experimental procedure followed the Standard of Association for Research in Vision and Ophthalmology. The license for animal administration was obtained. Results After intravitreous injection with celecoxib, the thickness and area of CNV were significantly smaller in celecoxib group than normal saline group on 14 days （69.75 μm ± 7.50 μm vs 45.84 μm ± 5.59μm in thickness and 87 854 pixel2 ＋ 6735 pixel2 vs 61 101 pixel2 ＋ 6314 pixel2in area, P = 0. 00）. The expressions of VEGF protein and mRNA were obviously lower in celecoxib group compared with normal saline group （t = 3. 755 ,P = 0.02;t = 3. 155, P = 0. 03 ）. No significant difference was found in expression of COX-2 mRNA between the two groups （ t = 0. 581, P = 0.59 ）. Conclusion Intravitreous injection of celecoxib can effectively inhibit CNV by downregulating VECF level,which is a new approach for the treatment of CNV.