Intravitreal LiCl injections activate the Wnt/β-catenin pathway following OIR, but have no influence on vessel regrowth into vaso-obliterated areas.

<p>A, B. Western blot analyses (A) and relative densitometry (B) for β-catenin in retinal proteins of FVB/n mice after exposure to 75% oxygen for five days from P7 and intravitreal application of LiCl (10 µg). After 6 h, in LiCl-injected eyes a significant increase of β-catenin levels was observed compared to PBS treated animals (mean ± SEM; n = 11 from 3 independent experiments; *p<0.05). D, E. Immunohistochemical staining for β-catenin (green) on retinal cryosections from FVB/n mice 6 h after intravitreal LiCl (10 µg) (E) or PBS injection (D) and oxygen-exposure until P12. After treatment with LiCl (E) an intense accumulation of β-catenin is seen in nuclei of the inner nuclear layer compared with PBS injected controls (D). Blue, DAPI staining. Scale bars: 50 µm. F–I. Representative retinal whole mounts of FVB/n mice that were perfused with FITC-labeled dextran at P13 after induction of OIR and intravitreal LiCl (1×10 µg; G, I) or PBS injection (F, H). Scale bars: 1000 µm. For quantification the area of vaso-obliteration (red in H, I) was quantified at P13 and plotted as percentage of total area of the superficial vascular plexus (C). No difference in the area of vaso-obliteration was observed between treated mice and control animals (mean ± SEM; n≥13 from 3 independent experiments).