Fig. 10

Representative immunohistochemical detection of epigenetic marks in human neocortex tissue array. Column a shows control temporal lobe obtained from a nonpathological surgical specimen that was fixed < 1 h after devitalization. Column b shows a frontal lobe specimen from a person who survived in a coma for 7 days after a severe hypoxic insult and whose autopsy (i.e., delay to fixation) was performed 31 h after death. Column c shows a nonpathological frontal lobe specimen from a person who died immediately after trauma and whose autopsy was performed 4 days after death. For all antibodies shown, in the control tissue almost all nuclei (except for those of scattered endothelial cells) are immunoreactive. 5mC immunoreactivity (top row) was reduced in some hypoxic neurons (arrow) and some small nuclei after prolonged delay to fixation (arrowhead). H3K27me3 (second row) immunoreactivity was unchanged in hypoxic brain (although cell shapes were altered). After prolonged delay to fixation, a few small nuclei were negative (arrowhead). H3K14ac (third row) immunoreactivity was diminished in approximately half the cells in hypoxic brain (arrows) and many neurons in the delayed fixation brain (arrowheads). H4K5ac (fourth row) immunoreactivity was unchanged in hypoxic brain but showed diminished intensity in the delayed fixation brain (arrowheads). Images taken at × 200 magnification. DAB detection of antibody (brown) and hematoxylin counterstain (blue)