Research ReportErythropoietin prevents nitric oxide and cathepsin-mediated neuronal death in focal brain ischemia

We examined the preventive effect of human recombinant erythropoietin (HrEPO) on nitric oxide (NO)-mediated toxicity to neurons and cysteine protease release into cytoplasm, which is attributed to neuronal death in brain ischemia. Focal cerebral ischemia was induced by permanent occlusion of middle cerebral artery in two sets of rat. The first set was used to monitor NO concentration and cathepsin activity, while the second was used for histological examination with hematoxylin and eosin, and TUNEL staining. A group in both set was administered human recombinant erythropoietin (HrEPO). NO content, cathepsins B and L activity increased significantly in the post-ischemic cerebral tissue (p < 0.05). HrEPO treatment reduced NO concentration and cathepsin activity to control level (p > 0.05). A significant increase in the number of necrotic and apoptotic neurons was observed in the post-ischemic cerebral cortex (p < 0.05). HrEPO treatment was markedly lowered both of these (p < 0.05). It is concluded that HrEPO prevents neuronal death by protecting neuronal liposomes from NO-mediated toxicity and suppressing the release of cathepsins.

Research Highlights► HrEPO reduces NO level, cathepsins B and L activity in ischemic brain tissue. ► HrEPO increases intact neurons after the permanent MCAO. ► HrEPO prevents necrotic and apoptotic neuronal death. ► HrEPO may be valuable agent in the treatment of stroke patients.