Poly(ADP-ribose) Polymerase Is Activated In Brain Edema Formation Induced By Hemoglobin After Intracerebral Hemorrhage In Rats

Intracerebral haemorrhage(ICH) is a subtype of stroke with high morbidity and mortality,which was reported to be associated with not only the location and size of hematoma but also secondary brain injury after ICH.Caused by secondary brain edema formation,many patients after ICH deteriorate progressively.Hence,brain edema formation after ICH may be one of the most important facts which lead to high morbidity and mortality.Object:The secondery brain edema induced by intracerebral hemorrhage (ICH) is one of the most important facts of secondary injury after ICH. However,the mechanisms of brain edema formation following ICH are not well understood.Several studies have found that hemoglobin played an important role in brain injury after ICH.In the present study,we sought to explore the mechanism of brain edema formation caused by hemoglobin.Methods:Hemoglobin was infused into the right basal ganglia of SD rats with stereotactic guidance.The animals were killed 24 hours later to detect brain water and ion contents.Meanwhile,Western blot analysis and immunohistochemical study were applied for Poly(ADP-ribose) polymerase(PARP) measurement.The effect of the iron chelator deferoxamine(DFX) on PARP activation was also examined.Results:Intracerebral infusion of hemoglobin caused an increase in brain water content and sodium ion at 24 hours.At the same time,PARP was upregulated after hemoglobin infusion.By the intraperitoneal injection of 500 mg/kg DFX,brain edema induced by hemoglobin was attenuated significantly and PARP was also downregulated.Conclusions:These results demonstrated that PARP might play a potentially important role,at least in part,in delayed edema development induced by hemoglobin after ICH,and reducding iron production by iron chelator and downregulating PARP overactivation might be a useful target for therapeutic intervention to limit brain edema after ICH.