UBC Theses and Dissertations
Moderate or deep local hypothermia does not prevent the onset of ischemia-induced dendritic damage Tran, Sherri
Apical dendrites of layer 5 pyramidal neurons can rapidly undergo a structural perturbation within minutes of ischemia onset. This “blebbing” is a morphological phenomenon in which dendrites display regions of spherical and/or ellipsoid swellings, resembling a “beads-on-a-string” appearance. We investigated the acute (up to 2 hours after reperfusion) effects of localised cortical hypothermia, a well-recognised neuroprotective strategy, on ischemia-induced dendritic structural damage. Using in vivo two-photon imaging combined with a global ischemia model of occluding the common carotid arteries in C57Bl/6 mice, we monitored in real time these dynamic structural alterations during ischemia and reperfusion. We show that moderate (31°C) and deep hypothermia (22°C) delays but does not block the onset of dendritic blebbing during global ischemia. Deep hypothermic treatment also tended to promote more consistent recovery of dendritic structure during reperfusion. These results suggest that those employing therapeutic hypothermia will need to consider that it does not spare neurons from structural changes that are the result of ischemia, but may interact with mechanisms that control the onset of damage and recovery during reperfusion.
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