Acute neuronal injury after hypoxia is influenced by the reoxygenation mode in juvenile hippocampal slice cultures.
In neonates asphyxia is usually followed by hyperoxia due to resuscitation procedures. In order to study whether hyperoxic reoxygenation might cause additional cell injury we subjected organotypic hippocampal slice cultures of juvenile rats to normoxic or hyperoxic reoxygenation (19 or 85% oxygen, respectively) following hypoxia (3% oxygen) for 30, 60, and 120 min. Cell injury was quantified by lactate dehydrogenase (LDH) release and propidium iodide (PI) fluorescence 1 h after end of the reoxygenation period. In both experimental groups, LDH activity was significantly enhanced by hypoxia as compared to normoxic controls. However, hyperoxic reoxygenation caused a larger increase in LDH activity than normoxic reoxygenation (e.g., by a factor of 1.60 vs. 1.29 following 120 min hypoxia). PI fluorescence increased after hypoxia in all principal cell layers of the hippocampus but again showed a larger enhancement after hyperoxic reoxygenation as compared to normoxic reoxygenation (e.g., by a factor of 3.9 vs. 1.7 for CA1 and 120 min of hypoxia). After normoxic reoxygenation, PI fluorescence intensity was lower in the dentate gyrus as compared to CA1 and CA3, while it reached similar values like CA1 after high oxygen supply. In conclusion, juvenile hippocampal slice cultures subjected to hyperoxic reoxygenation display a greater amount of acute neuronal injury than slice cultures undergoing normoxic reoxygenation.
Charité, Humboldt University Berlin, Department of Neonatology, Augustenburger Platz 1, D-13353 Berlin, Germany.
Johannes
J
Graulich
Ulrike
U
Hoffmann
Rolf F
RF
Maier
Karsten
K
Ruscher
Jörn K
JK
Pomper
Hae-Kyung
HK
Ko
Siegrun
S
Gabriel
Michael
M
Obladen
Uwe
U
Heinemann
D000367:Age Factors; D000818:Animals; D001238:Asphyxia Neonatorum / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D004396:Coloring Agents; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D018496:Hyperoxia / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology; D002534:Hypoxia, Brain / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D007231:Infant, Newborn; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009924:Organ Culture Techniques; D010100:Oxygen / Q000494:pharmacology*; D011419:Propidium; D051381:Rats; D017208:Rats, Wistar
D004396:Coloring Agents; D011419:Propidium; D007770:L-Lactate Dehydrogenase; D010100:Oxygen