Objective: To study the expression of vascular endothelial growth factor (VEGF), integrin alphavbeta3, and tissue factor (TF) in choroidal neovascularization (CNV).
Methods: CNV was induced in 25 Brown Norway (BN) rats by diode laser with 532 nm wave length. In every BN rat, one eye was induced to produce CNV, and the other eye served as the normal control eye. Fundus photography and fundus fluorescein angiography (FFA) were performed just before euthanasia on 3, 7, 14, 21, and 28 d after laser photocoagulation. The retina was processed for histopathology and immunohistochemical analysis to detect the expressions of VEGF, integrin alphavbeta3, and TF.
Results: There was no CNV, no expression of intergrin alphavbeta3 and TF in the normal control eyes. Only a few VEGFs were expressed in the ganglion cell layer of the retina, inner nuclear layer, retinal pigment epithelium, and vascular endothelial cell of the retina and choroid in normal eyes. FFA revealed disc-like leakage of fluorescein 7 days after the photo-coagulation, meaning there was CNV. VEGF, intergrin alphavbeta3, and TF were all expressed in the ganglion cell layer of the retina, inner nuclear layer, retinal pigment epithelium, and vascular endothelial cell of the retina and choroids 3 days after the photo-coagulation. With the development of CNV, expressions of integrin alphavbeta3, VEGF, and TF were gradually increasing (P<0.01). The expression of integrin alphavbeta3 in the retina was at peak on 7th day, VEGF on 14th day, and TF on 21st day.
Conclusion: Expressions of VEGF, integrin alphavbeta3, and TF in CNV were found at the early, middle and late stage of CNV formation. It is important to determine the time of anti-neovascularization.