Delayed and Reported Injections of Recombinant Human Erythropoietin Have No Beneficial Effect in Rats with Ischemic Stroke

Abstract

Background(s): Erythropoietin is known to have neuroprotective effects. Objective(s): This study was undertaken to evaluate whether delayed and repeated treatments with recombinant human erythropoietin (rhEPO) could improve neurobehavioral deficits caused by ischemic stroke. Method(s): Twenty ischemic stroke model rats in E-E group were injected via tail vein with 5 IU/g rhEPO once a week after injection of the same dose of rhEPO at reperfusion; 20 rats in E-S group with saline once a week after an initial injection 0f 5 IU/g rhEPO; 20 rats in S-E group with 5 IU/g rhEPO once a week after an initial injection of saline; and 20 rats in S-S group with saline once a week after an initial injection of saline. Neurobehavioral functions were assessed for 43days. To investigate mechanisms of rhEPO effects, the rats and 40 additional ischemic stroke model rats(20 rhEPO-treated vs. 20 saline-treated) were sacrificed at 43 days and 22h, respectively, after the initial injection. Result(s): When compared with the S-S group, neurobehavioral functions were improved in the E-E and E-S groups, but not in the S-E group. At 22 h, survival signals increased and infarct volume and death signals decreased in the rhEPO-treated rats, when compared with the saline-treated rats. At 43 days, nestin increased in the E-E and S-E groups but not in the E-S group, as compared with the S-S group. Conclusion(s): These findings suggest that delayed and repeated treatments with rhEPO have no beneficial effects in ischemic stroke, although acute treatment can improve neurobehavioral deficits.