Retina.

<p>(a-d): H&E retinal slices from control (a) and IHH animals at P14 (b-d) showing haemorrhage in the ganglion cell layer (b), inner nuclear layer (c) and outer nuclear cell layer (d). (e-h): Retinal wholemounts stained with endothelial-specific Biotinylated <i>Griffonia</i> (<i>Bandeiraea</i>) <i>Simplicifolia</i> Lectin I Isolectin B4 from controls at P28 with a mature vascular bed (e) and no vasculature extending beyond the ora serrata (f). Retinal vascular bed in IHH animal at P28 with less remodelling (g) and areas of vascularization beyond the ora serrata (h). (a-d): x400 magnification; scale bar = 50 μm. (e-h): x100 magnification; scale bar = 200 μm. Abbreviations, IHH, intermittent hyperoxia-hypoxia; P14, postnatal day 14; P28, postnatal day 28.</p

Litter differences in DTI metrics.

<p>Fractional anisotropy (a); mean (b), radial (c) and axial diffusivity (d) in white matter areas of litter A (grey columns, n = 13), B (black columns, n = 9) and controls (white columns, n = 8) on postnatal day 14. Mean, axial and radial diffusivity are shown in units of mm²/s. Data are presented as mean ± 95% confidence interval. Differences between litters are marked where significant (<i>p</i> < 0.05). Abbreviations: wm: all of white matter; bcc: corpus callosum (body); ec: external capsule; ic: internal capsule; IHH, intermittent hyperoxia-hypoxia; hf: hippocampal fimbriae. </p

Litter differences in T₂.

<p>T₂-relaxation time in the brain at P14 in litter A (grey columns, n = 13), litter B (black columns, n = 9) and C (white columns, n = 8) in the cortex (a), hippocampus (b), putamen (c) and thalamus (d). T₂-relaxation times are shown in milliseconds. Differences between litters are marked where significant (<i>p</i> < 0.05). Data are presented as mean ± 95% confidence interval. Abbreviations: IHH, intermittent hyperoxia-hypoxia; P14: postnatal day 14; P28: postnatal day 28. </p

Albumin.

<p>Albumin immunoreactivity (brown stain) at P14 (a-b) and P28 in controls (c-d) and IHH (e-f). Note positive immunoreactivity for albumin in both experiment groups at P14 and several spots of albumin immunoreactivity in the cortex and thalamus of the IHH animal at P28. Albumin is present in intracellular vesicles in neuroependymal cells in the ventricles (b & d). (g) The sum of positive scores for albumin leakage in the neuropil of the respective brain areas are presented as fractions of the maximum possible score in each experiment group at P28. (a, c & e): scale bar = 2 mm (b, d & f): scale bar = 50 μm at x400 magnification. Abbreviations: IHH, intermittent hyperoxia-hypoxia; P14, postnatal day 14; P28, postnatal day 28. </p

Vascular density.

<p>(a) Vascular density as % of controls (white columns, n = 4) in IHH animals at P14 (grey columns; IHH: n = 10) and P28 (black columns; IHH: n = 12). Data are expressed as mean ± 95% confidence intervals. (b-e) x400 magnification of lectin-stained endothelium in IHH (upper row) and control (lower row) at P14 (b & d) and P28 (c & e). *<i>p</i> = 0.005 IHH vs. control. Scale bar = 50 μm. Abbreviations: IHH, intermittent hyperoxia-hypoxia; P14, postnatal day 14; P28, postnatal day 28; pvwm, periventricular white matter. </p

Experimental profile of intermittent hyperoxia-hypoxia.

<p>Every sixth hour of hyperoxia (50% O₂) was interrupted by a cluster of three consecutive episodes of hypoxia (12% O₂) ten minutes apart, each of two minutes. This profile was applied continuously from within four hours after birth until postnatal day 14.</p

DTI on postnatal day 14.

<p>Fractional anisotropy (a); radial (b); mean (c) and axial diffusivity (d) in white matter areas of controls (grey columns, n = 8) and IHH (black columns, n = 22). Mean, axial and radial diffusivity are shown in units of mm²/s. Data are presented as mean ± 95% confidence interval.* <i>p</i> < 0.04. Abbreviations: wm: all of white matter; bcc: corpus callosum (body); ec: external capsule; ic: internal capsule; IHH, intermittent hyperoxia-hypoxia; hf: hippocampal fimbriae. </p

Rotarod testing.

<p>Mean time on a Rotarod on P20 and P27 of IHH (n = 12, black diamonds) and controls (n = 4, grey boxes). *<i>p</i> ≤ 0.03 IHH vs. control. Data are presented as mean ± 95% confidence intervals. Abbreviations: IHH, intermittent hyperoxia-hypoxia; P20, postnatal day 20; P27, postnatal day 27.</p