Abstract
Purpose :
In retinopathy of prematurity, high level of oxygenation is believed to cause vascular regression and development of retinal ischemic areas. In those areas, vascular endothelial growth factor (VEGF) is released and induces a variety of pathological distress including retinal neovascularization. Astrocyte induce normal angiogenesis during development in the retina and platelet-derived growth factor-A(PDGF-A) has been shown to stimulate production and differentiation of astrocyte. Yamada et al proved that PDGF-A plays an important role to suppress ischemic area by reducing hyperoxic damage to the retinal vessels. In this study, we investigated the mechanism how PDGF-A works as ischemia tolerance in the retina which exposed hypseroxic condition by comparing PDGF-A transgenic and wild-type mice.
Methods :
We used PDGF-A transgenic mice (Yamada et al, AJP 2000) and wild-type mice from C57BL/6NJ. Hyperoxia-induced retinopathy of prematurity (HIR) model was prepared by a commonly used method (Smith LE et al, Invest Ophthalmol Vis Sci 1994). After exposed to hyperoxia, mice were perfused with FITC-dextran from the left ventricle and the eyes were isolated. Retinal whole mounts and frozen sections were prepared. Sections were stained by GFAP, PAX2, and other antibodies(HIF,s100β) which are specific for astrocyte cells, and analyzed by confocal microscopy (FV3000,Olympus,Japan), then the area of retinal ischemic regions were measured using ImageJ software (Rasband, W.S., ImageJ, U. S. National Institutes of Health, Bethesda, Maryland, USA, http://rsb.info.nih.gov/ij/, 1997-2012.). The proteins which isolated from those retinas were analyzed for expression levels of GFAP, PAX2, and other proteins related to astrocyte cells (HIF,s100β)by Western blotting.
Results :
Retinal ischemic area in HIR mice was significantly less in the PDGF-A(+) group (1.38 ± 0.47 mm2) than those of PDGF-A(-) group (7.46 ± 1.14 mm2,p < 0.05). Protein expression of GFAP and PAX2 was enhanced in the PDGF-A(+) group compared to PDGF-A(-) group .
Conclusions :
PDGF-A enhances retinal astrocyte cell expression and this may cause retinal ischemia tolerance under hyperoxic conditions.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.