F4/80⁺ macrophages infiltrate ischemic retinas of both C57BL/6 and IL-10^−/− mice.

<p>Retinal flatmounts of P17, FITC-dextran perfused C57BL/6 normoxia-treated, C57BL/6 oxygen-treated, and IL-10^−/− oxygen-treated retinas were stained with Allophycocyanin (APC) anti-mouse F4/80 antibody. In contrast to the paucity of cells in the (A) normoxic wild-type retina, a significant number of F4/80⁺ macrophages are observed in the retinas of both (B) C57BL/6 oxygen-treated and (C) IL-10^−/− oxygen-treated mice. (D, E, F) Examining both macrophage infiltrate and blood vessels reveals that APC-labeled macrophages reside primarily along FITC-dextran perfused blood vessels. Since IL-10 did not prevent macrophage infiltration into the retina, we examined the genetic profile of retinal macrophages. Using splenic wild-type macrophages as a baseline, retinal macrophages from wild-type mice exhibit significantly (p<0.05) increased expression of the pro-angiogenic gene (G) nitric oxide compared to IL-10^−/− retinal macrophages following OIR, suggesting that IL-10 promotes angiogenesis by polarizing macrophages towards a pro-angiogenic phenotype.