Figure 2

TBI causes DNA damage 24 hours after impact. A. Photomicrographs of representative sections from rat cortex or hippocampus showing TUNEL histochemistry 24 hours after mild LFPI. TUNEL-positive nuclei (green fluorescence) were distributed throughout the ipsilateral cortex or hippocampus 24 h after TBI. Intense signals are observed as rims on the nuclear boundaries with a diffuse homogeneous signal on the interior of the nucleus. Arrows indicate the TUNEL positive nuclei. (Scale bar 500 μ). B. Histograms show the number of TUNEL-positive nuclei in the cortex or hippocampus 24 or 48 hours after TBI. Significant increase in the TUNEL-positive nuclei at the 24 h time point indicates the DNA damage occurs in these brain regions as early as 24 hours post-TBI although at 48 hours after TBI the damage was not significantly different in TBI animals compared to sham-treated animals. (** p < 0.001 compared to sham animals)