Figure 3. Recombinant human VEGF₁₆₅b significantly reduces PRNV and vessel tortuosity in the rat 50/10 OIR model.

Litters of 12-14 Sprague Dawley pups were raised with their dams under conditions of fluctuating oxygen levels between 50% and 10% every 24 hours, for the first 14 days of life. At P14 pups received IO injections of either anti-VEGF antibody, G6-31 (1μg) or rhVEGF₁₆₅b (25ng) in the ipsilateral eye and control injections in the contralateral eye. A) (i) Examples of control and treated microvasculature shown (White arrowheads indicate PRNV) (ii) G6-31 (p<0.05; n=8) and (iii) rhVEGF₁₆₅b (p<0.001; n=20) significantly reduced the number of clock hours showing PRNV (Mann-Whitney U test) and B) PRNV area relative to contralateral controls (Paired t-test). C) Neither G6-31 nor rhVEGF₁₆₅b were capable of significantly reducing retinal avascular area (P>0.05; paired t-test) however D) rhVEGF₁₆₅b significantly reduced arterial vessel tortuosity. E) Immunoblot for pan-VEGF and VEGF₁₆₅b showing expression of VEGF dimers and monomers in uninjected and expression in rhVEGF₁₆₅b injected eyes six days after injection. Densitometry shows a signficant upregulation of pan-VEGF but not VEGF₁₆₅b during OIR (*), and significantly increased VEGF₁₆₅b after rhVEGF₁₆₅b injection six days earlier (#). (*, #=p<0.05. NS=not significant).