Temporal profile of the effects of pretreatment with brief cerebral ischemia on the neuronal damage following secondary ischemic insult in the gerbil: cumulative damage and protective effects.
We examined the response of the gerbil brain to secondary ischemic insult following pretreatment with brief ischemia at intervals of 5 min, 1 and 6 h, 1, 2, 4, 7 and 14 days. Two minutes of bilateral carotid artery occlusion produced no histopathological brain damage, whereas 3 min of occlusion caused a moderate to severe reduction in the number of hippocampal CA1 pyramidal cells. Two-minute occlusion followed by 3-min occlusion at 5-min, 1- and 6-h intervals resulted in almost complete destruction of CA1 neurons. Additional neuronal damage was observed in the striatum at a 1-h interval and in the thalamus and the neocortex at 1- and 6-h intervals. The neuronal damage was most severe at a 1-h interval. Two-minute ischemia followed by 3-min ischemia at intervals of 1, 2, 4 and 7 days, however, caused a marked protective effect, and the hippocampal CA1 neurons were preserved. The protective effect was not observed at a 14-day interval and following pretreatment with 1-min ischemia. Thus, pretreatment with brief ischemia leads to complex responses of the brain to secondary ischemic insult; cumulative damage at intervals of 1-6 h and protective effects at intervals of 1-7 days.
Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.
H
H
Kato
Y
Y
Liu
T
T
Araki
K
K
Kogure
D000818:Animals; D001921:Brain / Q000473:pathology*; D002540:Cerebral Cortex / Q000473:pathology; D003342:Corpus Striatum / Q000473:pathology; D005849:Gerbillinae; D006624:Hippocampus / Q000473:pathology; D002546:Ischemic Attack, Transient / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D009474:Neurons / Q000473:pathology*; D011712:Pyramidal Tracts / Q000473:pathology; D013788:Thalamus / Q000473:pathology; D013997:Time Factors