[VEGF expression in dog retina after chorioretinal venous anastomosis].
OBJECTIVE
To identify changes in vascular endothelial growth 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 neovascular complications.


METHODS
Immediately after branch retinal vein occlusion (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 successful 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.
Lu
Ning
N
Beijing Tong Ren Ophthalmology Center, Capital University of Medical Sciences, Beijing 100730, China. plf@public3.bta.net.cn
Li
Zhihui
Z
Sun
Xianli
X
Wang
Guanglu
G
Zhang
Feng
F
Peng
Xiaoyan
X
D000818:Animals; D002829:Choroid / Q000098:blood supply* / Q000601:surgery; D004285:Dogs; D016228:Endothelial Growth Factors / Q000096:biosynthesis*; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis*; D008222:Lymphokines / Q000096:biosynthesis*; D012160:Retina / Q000737:chemistry* / Q000601:surgery; D012169:Retinal Vein / Q000601:surgery*; D012170:Retinal Vein Occlusion / Q000601:surgery*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D036341:Intercellular Signaling Peptides and Proteins; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors