PURPOSE: Components of the IGF system have been found to be modulated in the eyes of human diabetics and animal models of experimental hyperhexosemia. We sought to determine if the IGF system is altered from normal in the domestic pig model of preretinal NV induced by ischemia, with and without exogenous IGF-1 administration. METHODS: 25 pigs were treated with bilateral branch retinal vein occlusion, 16 pigs were injected intravitreally with 600ug of hrIGF-1 in one eye, one week post-BVO (the control eye received BSA) Pigs were sacrificed ii groups of four at 1,4,12, and 24 weeks post-injection. The 9 additional pigs were eft untreated and sacrificed in groups of 3 at 3, 7, and 28 days post-BVO. All vitreous samples were subjected to western ligand and immunoblotting. Each sample was studied for total protein MW spectrum with enhanced gold staining, all IGFBPs were labeled with I-IGF-II: and IGFBPs were specifically identified with rabbit, anti-human IGFBP-2, 3, and 4 antibodies RESULTS: All eyes showed a labeled band consistent with IGFRP-2 (BP-2), which was confirmed by immunoblotting. BP-2 levels were very high from 72 hrs post-BVO and were maintained at an eleva ed level throughout the study period compared to normals. Eyes injected with IGF-1 demonstrated increased BP-2 levels vs the control eyes in most groups. CONCLUSIONS: This is the first report demonstrating the presence of BP-2 in the pig vitreous and its modulation by experimental retinal ischemia (±exogenously delivered IGF-1). Because elevated BP-2 levels have also been found in the vitreous of humans with PDR, the IGF system may play a significant role in the pathophysiology of diabetic complications.
|Original language||English (US)|
|Journal||Investigative Ophthalmology and Visual Science|
|State||Published - Feb 15 1996|
ASJC Scopus subject areas
- Sensory Systems
- Cellular and Molecular Neuroscience