Dexamethasone prevents hypoxic-ischemic brain damage in the neonatal rat.

Glucocorticoid therapy is frequently used in perinatology and neonatology for its beneficial pulmonary effects. We investigated the influence of neonatal glucocorticoid administration on brain damage caused by a concurrent episode of cerebral hypoxia-ischemia. Various doses of dexamethasone in several treatment schedules were administered to 7-d-old rats that were also subjected to unilateral cerebral hypoxia-ischemia. In 79% of control rats, a large unilateral cerebral infarction occurred, whereas all rats pretreated with dexamethasone in doses of 0.01 to 0.5 mg/kg/d for 3 d had no infarction (p less than 0.001). The neuroprotective effect of dexamethasone pretreatment was dose- and time-dependent. Treatment with dexamethasone after the insult or with lower doses before the insult did not prevent infarction. The neuroprotective effect was not immediate: single doses 0 to 3 h prehypoxia were not effective but a single dose 24 h before hypoxia-ischemia prevented cerebral infarction. The results demonstrate that glucocorticoid administration in the neonatal period, even in low doses, protects the brain during subsequent periods of hypoxia-ischemia.