Fig.1: IVH reduced active β-catenin (ABC) and TCF4 in preterm rabbits.

A) Coronal brain slice from the fronto-parietal lobe of E29 rabbit pups which show slit like ventricles in pup without IVH (upper panel) and moderate to severe IVH resulting in fusion of the lateral ventricles (middle and lower panel). Scale bar, 1 cm. B) Representative Western blot analyses for total β-catenin (TBC), activated β-catenin (ABC) and TCF4 on brain homogenates of preterm rabbits with and without IVH at D3 and D7. The bar charts are mean ± s.e.m. (n = 5 each). Values were normalized to β actin levels. TBC levels were reduced in pups with IVH compared to both glycerol-treated and untreated controls without IVH at D7. ABC was reduced in rabbits with IVH compared to both glycerol and no glycerol controls without IVH at D7. ABC was also reduced in pups with IVH compared to glycerol treated controls without IVH at D3. TCF4 was also reduced in rabbits with IVH compared to controls without IVH at D7. C) mRNA expressions of Axin2 was reduced in rabbits with IVH compared to controls without IVH at D7. D) Representative immunofluorescence of cryosections from E29 rabbit pups with and without at D7 (as indicated) labeled with β-catenin and TCF4 specific antibodies. Note reduced expression of β-catenin and TCF4 in the VZ and SVZ of dorsal telencephalon of rabbits with IVH compared to controls without IVH. E) Cryosections were stained with TCF4 in combination with PDGFRα or Nkx2.2 specific antibodies. TCF4 immunoreactivity co-localized with PDGFRα extensively in the SVZ of dorsal telencephalon (arrowhead). TCF4 signals also overlapped with Nkx2.2 reactivity (arrowhead). Scale bar, 20 μm. *P<0.05, **P<0.01, ***P<0.001 glycerol treated no IVH controls vs. pups with IVH. ##P<0.01, ### P<0.001 pups not treated with glycerol vs. pups with IVH. VZ, ventricular zone; SVZ, subventricular zone.