玻璃体腔注射环孢菌素A对糖尿病大鼠血视网膜屏障的保护作用及机制

The protective effects and mechanism of intravitreal injection with cyclosporin-A on blood-retinal barrier in diabetic rats

目的观察和探讨玻璃体腔注射环孢菌素A（CsA）对糖尿病（DM）大鼠血视网膜屏障（BRB）的影响及其作用机制。方法8～10周龄健康Sprague—Dawley雄性大鼠48只，随机分为正常对照组、DM组、CsA组及二甲基亚砜（DMS0）组，每组12只。对DM、CsA及DMSO组大鼠进行一次性腹腔注射链脲佐菌素（STZ）溶液建模，正常对照组大鼠腹腔注射等量的柠檬酸钠缓冲液。注射后72h，采用免疫组织化学染色法检测视网膜内外渗的内源性白蛋白评价BRB的渗透性；蛋白质免疫印迹法（Western blot）检测视网膜细胞间粘附分子（ICAM-1）的蛋白表达；酶联免疫吸附试验（EusA）检测视网膜血管内皮生长因子（VEGF）的表达。结果与正常对照组相比，DM组大鼠视网膜外渗的白蛋白增多，视网膜内ICAM一1、VEGF表达明显升高，差异均有统计学意义（F=29．350，29．240，9．658；P〈0．01）。与DM组相比，CsA组大鼠视网膜外渗的白蛋白减少，视网膜内ICAM-1、VEGF表达明显下降，差异均有统计学意义（t=3．174，5．000，3．352；P〈0．05）；DMSO组大鼠视网膜外渗的白蛋白、视网膜内ICAM-1及VEGF表达均无明显变化，差异无统计学意义（t=0．420，0．561，0．312；P〉0．05）。结论玻璃体腔注射CsA对DM大鼠BRB具有保护作用。其机制可能与CsA降低IcAM-1及VEGF的表达有关。

Objective To investigate the protective effect and mechanism of intravitreal injection with cyclosporiwA（CsA） on blood-retinal barrier （BRB） in diabetic rats. Methods A total of 48 Sprague- Dawley male mice at the age of 8-10 weeks were divided into normal group, diabetes mellitus （DM） group, CsA group and DMSO group, with 12 rats in each group. The rats in DM, CsA group and DMSO group were induced with streptozotocin （STZ） injection creating a diabetic retinopathy model. The same volume of citric sodium citrate buffer was injected into the rats in the normal group. Immunohistochemical staining was used to detect the BRB permeability, Western blot was used to measure the protein expression of intercellular adhesion molecule （ICAM-1）. Enzyme-linked immunosorbent assay （ELISA） was used to measure the expression of vascular endothelial growth factor 72 hours after injection. Results Compared with the normal group, the BRB permeability, ICAM-1 and VEGF expression were significantly increased in DM group （F=29. 350, 29. 240, 9. 658; P〈0.01）. Compared with the DM group, the BRB permeability, ICAM-1 and VEGF expression were significantly decreased in CsA group （t = 3. 174, 5. 000, 3. 352; P〈0.05） ; but there was no obvious change of above indexes in DMSO group （t=0. 420, 0. 561, 0. 312; P〉 0.05）. Conclusion Intravitreal injection of CsA has protective effects on BRB in diabetic rats. Downregulated expression of ICAM-1 and VEGF may be the mechanism.