Background and Purpose-Recent studies suggest that statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) not only reduce the incidence of stroke by lowering cholesterol levels but may also exert neuroprotective effects via a mechanism not related to their lipid-lowering effect. Despite the growing body of evidence, however, the neuroprotective effect of statins in stroke is still controversial. Herein, we studied whether a prophylactic administration of simvastatin (Sim) provides significant protection against brain damage, and we sought to determine its long-lasting behavioral consequences in a neonatal model of hypoxia/ischemia. Methods-Newborn male rats were injected daily from postnatal days 1 to 7 with activated Sim (20 mg/kg) or an equivalent volume of vehicle. On postnatal day 7, the rats were subjected to ligation of the right common carotid artery, followed by 3 hours of hypoxia or by sham operation. The neuroprotective effect of Sim was evaluated after the rats had achieved adulthood by using a battery of behavioral tests and histological analysis. Results-Sim-treated ischemic rats performed the circular water maze, the radial arm maze, and the multiple-choice water maze significantly better than did vehicle-treated ischemic rats. Furthermore, in contrast to the ischemic rats, hypoxia/ischemia-injured rats pretreated with Sim were not hyperactive at weaning and showed less behavioral asymmetry. Consistently, it was found that brain damage was significantly attenuated. Conclusions-These findings indicate that prophylactic administration of statins may provide a potential neuroprotective strategy leading to an improvement in functional outcome in ischemic stroke. However, toxicity concern must be addressed before these agents can be directed to the asphyxiated fetus or newborn. Key Words: cerebral ischemia Ⅲ HMG-CoA reductase inhibitors Ⅲ neuroprotection Ⅲ newborn Ⅲ rats I schemic stroke is one of the leading causes of permanent disabilities and death in the elderly. Stroke also commonly occurs in the perinatal period and can have severe consequences on motor, cognitive, and behavioral functions that span the infant's lifetime. The mechanisms of hypoxia/ischemia (HI)-induced brain damage, the behavioral outcome, and the effect of potential pharmacological treatments during development can be studied in 7-day-old rats subjected to unilateral carotid artery ligation and exposure to a hypoxic environment for 2 to 3 hours. [1][2][3][4] In terms of brain development, this age of the rat is similar to that of near-term human babies. 5 In a recent study, we characterized the long-lasting behavioral alterations occurring in this model of neonatal HI and found that these animals, when adults, show behavioral asymmetry and deficits in performing spatial learning tasks. 4 Therefore, these behavioral abnormalities can be used as an end point to evaluate the efficacy of potential pharmacological treatments that may improve the consequences of a perinatal HI insult.Recent clinical studies have reported ...