Poly(ADP-ribose) polymerase activation and brain edema formation by hemoglobin after intracerebral hemorrhage in rats.

Brain edema induced by intracerebral hemorrhage (ICH) is a serious problem in the treatment of ICH. However, the mechanisms of brain edema formation following ICH are not well-understood. We have found that hemoglobin plays an important role in edema development after ICH. In this study, we sought to explore the mechanism of brain edema formation caused by hemoglobin. Hemoglobin was infused into the right basal ganglia of male Sprague-Dawley rats. The animals were killed 24h later to detect brain water and ion content. Meanwhile, Western blot analysis and immunohistochemical studies were applied for Poly(ADP-ribose) polymerase (PARP) measurement. The effect of the iron chelator, deferoxamine, on PARP activation was also examined. We found that intracerebral infusion of hemoglobin caused an increase in brain water content at 24h. At the same time, PARP was activated after hemoglobin infusion. Deferoxamine (500 mg/kg, i.p.) reduced hemoglobin-induced brain edema and activation of PARP. These results demonstrate that hemoglobin can cause brain edema and activate PARP in rat brain.