Abstract
Purpose :
The mechanism of basic fibroblast growth factor (bFGF) in angiogenesis process became clear by accumulating knowledges. But the role of bFGF in the mechamism in ocular neovascularization is not clear enough. This is because angiogenesis process has not been continuously observed in the same individuals especially in ophthalmology field. We think optical coherence tomography angiography (OCTA) can improve this congestion. We made laser-induced choroidal neovascularization (Li-CNV) model mouse using a transgenic mouse that expresses excess bFGF only in the retinal photoreceptor cells (bFGF-tg) and observed over time using OCTA. The purpose of this study is to investigate the role of bFGF in angiogenesis process of choroidal neovascularization.
Methods :
Firstly, we made Li-CNV model mouse which is 6-week-old bFGFtg (C57bl/6J) and wild type (bFGF negative mice of litter: Wt). Secondly, low-power PCs which do not destroy Bruch's membrane, to induce the expression of bFGF at 7 days after initial PC. We performed OCTA observation over time. After sacrificing the animal, choroidal flat mount were made and immunohistochemistry were performed by αSMA.
Results :
The areas of Li-CNV in bFGF-tg after initial PC was significantly larger than those of Wt (p=0.0319). The areas of Li-CNV in the additional PC group were significantly larger than those of no additional PC group in both bFGF-tg (p=0.0163) and Wt (p=0.0051). Interestingly, angiogenesis occurred from existing Li-CNV in the initial PC area instead of additional PC area, and then neovascular vessels were branching and extending toward additional PC area. The additional PC group showed not only expansion of neovascularization area, but augmented mature vessels surrounded by αSMA antibody-positive cells. The additional PC group in bFGF-tg showed significant involution delay of CNVs compared to those of no additional PC group (p=0.0127).
Conclusions :
Over-supplying bFGF in the early process of angiogenesis promoted massive neovascularization but did not affect vessel involution. However, endogenous supply of bFGF to CNVs occurred at day 7 after initial PC resulted in delayed involution of Li-CNVs. As a results, we concluded that bFGF works for stabilization and mainteining of the pre-existing neovascular vessels.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.