Histopathological alterations and functional brain deficits after transient hypoxia in the newborn rat pup: a long term follow-up.
To assess temporal brain deficits consecutive to severe birth hypoxia, newborn rats were exposed for 20 min to 100% N2. This treatment induced a long-term growth retardation and a delayed, but only transient, neuronal loss (approximately 25%) in the CA1 hippocampus and parietal cortex, starting from 3 days and peaking at 6 days post-hypoxia. The expression profiles of various apoptosis-regulating proteins (including Bcl-2, Bax, p53 and caspase-3) were well correlated to the alterations of nuclear morphology depicted by 4,6-diamidino-2-phenylindole (DAPI). Whereas they confirmed a gradual histological recovery, specific DNA fragmentation patterns suggested that birth hypoxia may transiently reactivate the developmental programme of neuronal elimination. Although they successfully achieved various behavioral tests such as the righting reflex, negative geotaxis, locomotor coordination, and the eight-arm maze tasks, both developing and adult hypoxic rats were repeatedly slower than controls, suggesting that birth hypoxia is associated to moderate but persistent impairments of functional capacities.
INSERM EMI 0014, Université Henri Poincaré, Nancy, France.
Stéphanie
S
Grojean
Henri
H
Schroeder
Grégory
G
Pourié
Christiane
C
Charriaut-Marlangue
Violette
V
Koziel
Didier
D
Desor
Paul
P
Vert
Jean-Luc
JL
Daval
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D002452:Cell Count / Q000379:methods; D005500:Follow-Up Studies; D002534:Hypoxia, Brain / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology*; D018782:Maze Learning / Q000502:physiology; D009043:Motor Activity / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors