Fig. 4.

Astrocyte patterning is abnormal in NOIR mice. (A,B) En-face confocal images of midperipheral retina stained for astrocyte nuclei (Sox9) and vasculature (IB4 lectin; A), or for astrocyte arbors, labeled by anti-GFAP (P12) or anti-PDGFRα (P4) (B). Control astrocytes and their arbors were homogenously distributed, both in vascularized and avascular retina (A,B). In NOIR retinas, astrocyte somata aggregated in clumps and strings ahead of vascular wavefront (A) generating gaps in arbor coverage (B). Gap size varied across NOIR animals but most (n=5/9) exhibited ≥100 µm diameter gaps as shown (A,B). Advancing endothelial cells (red) remained associated with mispatterned astrocytes (A,B). (C) In P12 NOIR animals, retinal vascular coverage is inversely correlated with total astrocyte number. Line slope deviated significantly from zero (F=29.53; DFn,d=1, 9; P=0.0004). (D) NOIR retinas with vitreous hemorrhage (e.g. Fig. 2A) have significantly more astrocytes than NOIR retinas without hemorrhage. Two-tailed t-test: no hemorrhage, 23,721±2982 total astrocytes, n=6; vitreous hemorrhage, 48,895±4220, n=5; *P=0.0015. Scale bars: 200 µm. Error bars, mean±s.d.