Previous studies have shown contradictory results regarding magnesium-mediated neuroprotection in animal models of perinatal asphyxia. The aim of this study is to investigate the e fects of MgSO4 postasphyxial treatment on hypoxia-ischemia (HI)—induced brain injury in neonatal rats and the possibility that this e fect is related to the severity of brain damage. Seven-day-old rats underwent unilateral carotid artery ligation followed by 1 or 2 hours of hypoxia (8% O2) and MgSO4 administration. Adenosine triphosphate/phosphocreatine and glutamate/glutamine measurements and neuropathological evaluation of the hippocampus were used to assess the e fects of HI and MgSO4. HI caused time-dependent changes in energy stores, amino acid concentrations, and brain damage. Administration of MgSO4 after 1 hour but not after 2 hours of hypoxia resulted in significant prevention of HI-induced brain injury. MgSO4 administration results in a significant protection against moderate HI-induced brain damage, whereas it fails to offer a similar effect against severe brain damage.
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