The Effects of Erythropoietin on Learning and Memory in Rats with Alzheimer's Disease

Alzheimer’s disease is a prevalent disease resulting in learning and memory impairments. Recently, erythropoietin (EPO) has been demonstrated to improve cognitive functions and to have neuroprotective effects. This study aimed to evaluate the effects of erythropoietin on learning and memory in rats after intracerebroventricular (ICV) injection of streptozotocin (STZ), a well defined model for Alzheimer’s disease. To produce Alzheimer’s disease model in rats, STZ was infused in lateral ventricles of the brain. Two weeks later, the rats were tested by passive avoidance learning test to confirm the induction of learning and memory impairments. They then received EPO (5000 IU/kg) once every two days for two weeks. Finally, behavioral tests were conducted again. A reduction in time delay for the first entrance of rats to dark chamber as a result of ICV-STZ was found; i.e. there was a significant deference between the sham and the ICV-STZ groups. Although EPO did not have any significant effects on time delay for the first entrance to dark chamber in the sham group, it prevented impairments resulting from ICV-STZ. In fact, the index significantly increased in the STZ-EPO group compared to the STZ group. However, there was not a significant difference between the STZ-EPO and sham groups. The present results suggest use of EPO to probably cause significant improvements of learning and memory defects in Alzheimer’s patients.