Effects of progesterone and testosterone on ICH-induced brain injury in rats.

Studies have shown that progesterone reduces brain injury, whereas testosterone increases lesion size after ischemic stroke. This study examined the effects of progesterone and testosterone on intracerebral hemorrhage (ICH)-induced brain injury. Male Sprague-Dawley rats received an injection of 100 μL autologous whole blood into the right basal ganglia. Progesterone (16 mg/kg), testosterone (15 mg/kg) or vehicle was given intraperitoneally 2 h after ICH. Behavioral tests were performed, and the rats were killed after 24 h for brain edema measurement. Perihematomal brain edema was reduced in progesterone-treated rats compared to vehicle-treated rats (p<0.05). Progesterone also improved functional outcome following ICH (p<0.05). Testosterone treatment did not affect perihematomal edema formation, but resulted in lower forelimb placing score (p<0.05). In conclusion, progesterone can reduce brain edema and improve functional outcome, whereas testosterone may have a deleterious effect after ICH in male rats.