The protective effect of hypoxic preconditioning on cortical neuronal cultures is associated with increases in the activity of several antioxidant enzymes.
Preconditioning describes a variety of treatments that induce neurons to become more resistant to a subsequent ischemic insult. How preconditioned neurons adapt to subsequent ischemic stress is not fully understood, but is likely to involve multiple protective mechanisms. We hypothesized hypoxic preconditioning induces protection by a coordinated up-regulation of antioxidant enzyme activity. To test this hypothesis, we developed two in vitro models of ischemia/reperfusion, involving oxygen-glucose deprivation (OGD) where neuronal cell death was predominantly by necrosis (necrotic model) or programmed cell death (PCD model). Hypoxic preconditioning 24 h prior to OGD significantly reduced cell death from 83% to 22% in the necrotic model and 68% to 11% in the PCD model. Consistent with the hypothesis, the activity of the antioxidant enzymes glutathione peroxidase, glutathione reductase, and Mn superoxide dismutase were significantly increased by 54%, 73% and 32%, respectively, in neuronal cultures subjected to hypoxic preconditioning. Furthermore, superoxide and hydrogen peroxide concentrations following OGD were significantly lower in the PCD model that had been subjected to hypoxic preconditioning.
Arthur
P G
PG
Department of Biochemistry, The University of Western Australia, Crawley, WA 6009, Australia. parthur@cyllene.uwa.edu.au
Lim
S C C
SC
Meloni
B P
BP
Munns
S E
SE
Chan
A
A
Knuckey
N W
NW
D000818:Animals; D002545:Brain Ischemia / Q000201:enzymology / Q000517:prevention & control; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002374:Catalase / Q000378:metabolism / Q000627:therapeutic use; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology*; D003497:Cyclic N-Oxides / Q000378:metabolism / Q000627:therapeutic use; D004195:Disease Models, Animal; D004622:Embryo, Mammalian; D005947:Glucose / Q000172:deficiency; D006861:Hydrogen Peroxide / Q000378:metabolism; D000860:Hypoxia; D007211:Indoles; D019194:Ischemic Preconditioning / Q000379:methods*; D009474:Neurons / Q000201:enzymology* / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D051381:Rats; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors
D003497:Cyclic N-Oxides; D007211:Indoles; D013481:Superoxides; C007293:DAPI; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; D002374:Catalase; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D005947:Glucose; C003959:TEMPO