Transient ADC change precedes persistent neuronal death in hypoxic-ischemic model in immature rats.
A brief ischemia causes delayed neuronal death (DND) in some areas vulnerable to ischemia. Additionally, it causes a transient reduction in the apparent diffusion coefficients (ADCs) obtained from diffusion-weighted magnetic resonance imaging (DWI), which is a powerful tool to detect ischemic changes in the brain at a very early stage. The present study examined long-term histopathological changes in the hippocampal neurons up to 30 days after a very mild hypoxic-ischemic (HI) insult in immature rats. Three-week-old male rats were subjected to 15- and 30-min HI insults (15-min HI and 30-min HI) and serial DWI was performed. Only animals whose ADC reduction pattern was transient were examined histopathologically. ADCs decreased significantly during the insult, and the ADC values of 30-min HI group were significantly lower than those of 15-min HI group. Ischemic neuronal changes were observed up to 30 days after the insult in 30-min HI group, although ADCs in the chronic stage were within the normal range. In addition, neuron density in 30-min HI group was significantly lower in the chronic stage (on days 14 and 30) than in 15-min HI group. A very mild hypoxia-ischemia followed by a transient ADC reduction causes persistent neuronal death, which can be predicted by measuring ADCs during the acute insult.
Haku
Tomoko
T
Department of Comprehensive Reproductive Medicine, Graduate School of Medicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. t.haku.crm@tmd.ac.jp
Miyasaka
Naoyuki
N
Kuroiwa
Toshihiko
T
Kubota
Toshiro
T
Aso
Takeshi
T
D000818:Animals; D000831:Animals, Newborn; D016923:Cell Death / Q000502:physiology; D003627:Data Interpretation, Statistical; D004058:Diffusion; D006624:Hippocampus / Q000473:pathology; D020925:Hypoxia-Ischemia, Brain / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009474:Neurons / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley