the parenchyma of the control plasmid treated eyes had a top amount of staining as much of the HRP had leaked from within the vessel lumen. The leakiness of the retinal vessels was quantified by evaluating HRP densities within vessel lumens and in the surrounding pifithrin muscle parenchyma using the normal intensity function of the LSM510 software. This was decided in 4 fields of view and expressed as a ratio where in fact the price for a P17 age matched healthy mouse was used as the denominator, resulting in the age matched handle mouse having a HRP leakage index of 1. Throughout the period of OIR, the neovasculature of the non injected eyes had an HRP loss index of 0. 87560. 006 in the superficial plexus and 0. 89060. 014 in the deep plexus. The HRP loss index in plasmid injected retinas were 0. 84760. 016 in 0 and superficial plexus. 833 0. 033 in deep plexus. In comparison, IGFBP 3 inserted eyes had a HRP loss list of 1. 02360. 025 in the superficial plexus in comparison with 1. 07060. 051 in the deep plexus with an index of 1 for the agematched control eyes indicative of the improved barrier function of the neovascularization of the OIR product with Inguinal canal IGFBP 3 plasmid injection. This improvement of the BRB by IGFBP 3 plasmid injection is accompanied by substantial normalization of the vessel morphology. The capillary tree had near normal vessel caliber and meshwork morphology. More over, the vessel lumens were seen as an retention of HRP reaction product, causing a very light parenchyma without clear HRP loss. When the IGFBP 3 plasmid injected pups considering the OIR model were in comparison to normal healthy P17 pups reared in Cyclopamine structure normal oxygen from birth, the P17 mice had related retinal vessel morphology and barrier properties as the IGFBP 3 injected eyes of the OIR model. IGFBP 3 Protects Retinal Endothelial Cells from VEGFinduced Loss of Junctional Integrity As a way to better understand the protective function of IGFBP 3 on retinal vascular permeability, we have evaluated the impact of IGFBP 3 on VEGF induced disruption of junctional complexes by doing immunohistochemistry of claudin and vascular endothelial cadherin in monolayers of bovine retinal microvascular endothelial cells. VEGF therapy triggered dissociation of claudin and VEFigure cadherin by 3 hrs and this dissociation tended to recoup by 12 hrs, as shown in Figure 2. IGFBP 3 alone didn’t have any influence on the integrity of junctional complexes at 3 and 12 hrs of treatment. However, while in the existence of IGFBP 3, VEGF induced dissociation of VE and claudin cadherin was completely blocked. These suggest that the defense from vascular leakage by IGFBP 3 seen in the in vivo studies may be, in part, due to rescuing the integrity of junctional complexes from the deleterious effects of VEGF. Improved VEGF expression within the phase of the OIR model is well established.