Regional Differences in Susceptibility to Hypoxic-Ischemic Injury in the Preterm Brain: Exploring the Spectrum from White Matter Loss to Selective Grey Matter Injury in a Rat Model

Figure 3

Significant grey matter injury accompanies myelin basic protein (MBP) loss in postnatal day 6 (P6) neonatal rats. Grey matter injury, as determined by neuronal and axonal degeneration, increases in hypoxic-ischemic neonatal rats with the severity of white matter injury. Representative photomicrographs show Grade 1 MBP loss (a), with mild cortical neuronal degeneration (FJB staining, (b)) and axonal injury (fractin immunoreactivity, (c)). With Grade 2 MBP loss (d), the density and distribution of FJB-positive neuronal cell bodies (e) and fractin-positive axons (f) increase in the cortex overlying the periventricular white matter. With Grade 3 MBP loss (g), the density of FJB-positive neuronal cell bodies (h) and fractin-positive spheroids (i) are further increased and encompasses the majority of the cortical mantle, as well as the hippocampus, thalamus, caudate putamen, and internal capsule. Histograms display region-specific neurodegeneration (j) and axonal injury (k) in relation to the severity of white matter loss. Magnification 100x for MBP and 25x for FJB and fractin.