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

A–D. Western blot analyses (A, C) and relative densitometry (B, D) for β-catenin in retinal proteins of normoxic control FVB/n mice or after exposure to 75% oxygen for five days from P7 and intravitreal PBS injection or i.p. treatment with LiCl at P12. A, B. In retinal proteins from mice 6 h after oxygen exposure and intravitreal PBS injection no difference in β-catenin protein level were detected when compared to normoxic control littermates (mean ± SEM; n = 5 from 2 independent experiments). C, D. In contrast, in LiCl-injected mice a significant increase of β-catenin levels was observed when compared to PBS treated animals (mean ± SEM; n = 13 from 3 independent experiments; *p<0.05). E–I. Representative retinal whole mounts of FVB/n mice that were perfused with FITC-labeled dextran at P14 after induction of OIR and i.p. LiCl (3×50 µg/g body weight, 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 P14 and plotted as percentage of total area of the superficial vascular plexus (E). No difference in the area of vaso-obliteration was observed between treated mice and control animals (mean ± SEM; n≥13 from 4 independent experiments).