Fig. 1

Neuroprotection by hypothermia develops over time. Histological brain injury was determined in cresyl violet stained tissue sections 1, 3 and 7 days after HI, performed in 9-day-old C57Bl/6 mice. Animals were exposed to 4 h hypothermia immediately after HI. Controls were kept at physiological body core temperature (normothermia). Representative images of injured hemispheres for each experimental group are shown in a, scale bar: 1 mm. Injury scores were assessed in different brain regions (cortex, hippocampus, thalamus and striatum) resulting in a sum score, which was quantified for each animal (b). Brain atrophy was analyzed by measurement of intact tissue volumes at a distance of 400 μm between + 1 mm and − 2.6 mm from bregma and volumes were calculated for total hemispheres (c). Tissue loss is expressed as the percentage of volume reduction compared to intact contralateral volumes (c). *p < 0.05, **p < 0.01, n = 7/treatment and timepoint