RESUMEN
PURPOSE: To examine the effects of retinal vein occlusion (RVO) on VEGF expression and the ultrastructural change of the various ocular tissues in the rat. METHODS: Sprauge Dawley rats were grouped into RVO group induced with argon laser (n=30) and control (n=10). The ocular tissues of the rats were collected on the first, third and seventh day after RVO. VEGF expression was evaluated with immunohistochemical stain, and the ultrastructural changes were observed with electron microscopy. RESULTS: In control group, VEGF stain was positive in various ocular tissues except outer nuclear cells. In RVO group, VEGF expression had gradual increase in the inner nuclear layer, the retinal pigment epithelia and the ciliary body epithelia after RVO. Especially, in the retinal pigment epithelia, VEGF was significantly increased on the seventh day. In electron microscopic examination, degenerative changes had gradual increase in the inner and middle retinal layers after RVO. The degenerative changes in the retinal pigment epithelia were noted on the third day, and in the retinal photoreceptor cells on the seventh day. CONCLUSIONS: These results showed that VEGF expressions in the inner nuclear layer, retinal pigment epithelia and ciliary body epithelia had a gradual increase, and the ischemic damages of the retina and the optic nerve progressed from the inner layer to the outer layer after RVO.