Gender differences in long-term beneficial effects of erythropoietin given after neonatal stroke in postnatal day-7 rats

Abstract Recently, we reported that erythropoietin attenuates neonatal brain injury caused by focal cerebral ischemia. The long-term effects of erythropoietin on focal cerebral ischemia-induced injury to the developing brain and the potential gender differences in these long-term effects have not been studied in detail. The current study demonstrated a similarity in the mean infarct volume in both the vehicle-treated male and female rats at 6 and 12 weeks after focal cerebral ischemia. On the other hand, erythropoietin treatment (1000 U/kg×three doses after focal cerebral ischemia) caused a significant reduction in the mean infarct volume in both males and females at 6 weeks after focal cerebral ischemia when compared with the corresponding vehicle-treated animals (males: 141.4±48.2 mm 3 vs. 194.0±59.2 mm 3 , P 3 vs. 183.4±46.3 mm 3 , P 3 vs. 85.4±31.6 mm 3 , P 3 ( P 3 ). Additionally, erythropoietin treatment significantly improved sensorimotor function recovery with a misstep number similar to the sham-operation group at 6 and 12 weeks after focal cerebral ischemia. Moreover, the mean number of missteps in the erythropoietin-treated females was less than that in males at 6 (13.5±2.0 vs. 24.5±2.5, P P