狗脉络膜-视网膜静脉吻合术后视网膜血管内皮生长因子的表达

VEGF expression in dog retina after chorioretinal venous anastomosis

目的 通过研究狗脉络膜 视网膜静脉吻合术后视网膜的血管内皮生长因子 (vascularendothelialgrowthfactor,VEGF)的表达情况 ,探讨脉络膜 视网膜静脉吻合术与脉络膜新生血管(choroidalneovascularisation ,CNV)形成之间的关系。方法 对 5只实验狗的右眼行脉络膜 视网膜静脉吻合术 ,每只眼用激光治疗 2或 3个部位 ,1次治疗不成功者重复治疗。对侧眼作正常对照。在吻合血管形成部位及对照眼的相应部位取材做VEGF免疫组化染色。结果 正常狗的视网膜VEGF免疫组化染色呈阴性或弱阳性。经单次治疗的眼 ,VEGF表达量与正常对照组相比 ,差异无显著意义(P >0 0 5 ) ;经多次治疗的眼 ,在瘢痕组织内VEGF表达增强。结论 狗脉络膜 视网膜静脉吻合术中单次激光治疗不导致VEGF表达量增加 ,而过重的激光损伤可导致VEGF表达量增加 ,其原因可能与CNV的形成有关。

Objective To identify changes in vascular endothelial grouth factor (VEGF) expression in the dog retina after laser induced chorioretinal venous anastomosis (CRVA), in order to find out the relationship between CRVA treatment and the related neovacular complications. Methods Immediatley after branch retinal vein occlosion (BRVO) model was made in 5 eyes of 5 normal dogs, CRVA treatment was done over a small tributary vein in the drainage distribution of the occluded vein. In each eye, there were 2 3 treatment sites. Four to six weeks later, a repeated treatment was given if the first treatment failed to show the anastomosis. The treatment sites with successful CRVA were divided into two groups: the small laser spot group, which received one treatment and the big laser spot group, which received more than one treatment. The expression of VEGF was investigated immunohistochemically in the treatment sites with successful anastomoses and in the 5 normal fellow eyes (control). Results There were totally 10 succesful anastomoses in the 5 experimental eyes, among which, five received one treatment and the other 5 received more than one treatment. On fundus examination, the small laser spots were round and small, and the big laser spots were large with local proliferation. VEGF immunoreactivity was absent/weak in the normal dog retina,and remained unchanged in the small laser spot group, but somewhat increased in the big laser spot group. No neovascular complications occurred. All immunostaining experiments were accompanied by proper controls and none of the negative controls showed any immunoreactivity. Conclusions Proper laser treatment can induce CRVA quite safely in nonischemic dog retina, which does not cause changes in the expression of VEGF, but severe laser damage in the treatment site can cause increased VEGF expression which may be related to neovascular complications.