Nuclear condensation and fragmentation following cerebral hypoxia-ischemia occurs more frequently in immature than older rats.
Apoptotic cell death is associated with condensation and fragmentation of the nuclear chromatin into apoptotic bodies. Such nuclei occur frequently following cerebral hypoxia-ischemia in 1 week old rats but seem sparse in older animals. We investigated the age dependence by counting pyknotic or punctate chromatin containing cells in the cerebral cortex of 1,2 and 4 week old animals subjected to cerebral hypoxia-ischemia. In 1 week old animals the majority of injured neurons in the cortex had nuclei with punctate condensed chromatin but few were pyknotic. In the 2 and 4 week old animals the majority of injured cells were pyknotic (P < 0.002). Electron microscopic studies demonstrated the presence of apoptotic bodies. The results suggest that immature brain retains a part of the developmental cell death "program' that is activated following hypoxia-ischemia.
Sidhu
R S
RS
Biosystems, Institute for Biodiagnostics, National Research Council Canada, Winnipeg, Canada.
Tuor
U I
UI
Del Bigio
M R
MR
D000375:Aging / Q000502:physiology*; D000818:Animals; D017209:Apoptosis; D001927:Brain Diseases / Q000473:pathology*; D002545:Brain Ischemia / Q000473:pathology*; D002467:Cell Nucleus / Q000648:ultrastructure*; D002540:Cerebral Cortex / Q000473:pathology; D002843:Chromatin / Q000648:ultrastructure*; D000860:Hypoxia / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar
D002843:Chromatin