Influences and mechanism of erythropoietin on the cognitive function of vascular dementia rats

Purpose: To investigate the influences and mechanism of erythropoietin (EPO) on the cognitive function of vascular dementia (VD) rats. Methods: 1) Spatial memory capacity was assessed by Morris water maze test; 2) Pathological conditions of brain tissues were detected by hematoxylin-eosin (HE) staining; 3) The effect of treatment on apoptosis was observed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining; 4) Western blotting was used to examine the protein expression in hippocampal neurons. Results: The escape latency and swimming distance in the EPO group were much shorter than those in the Model group on the fifth day. In the spatial exploration test, the time spent in the target quadrant was longer, the number of platform crossings was larger and the swimming speed was higher in the Sham group and EPO group than those in the Model group. The results of HE staining showed that the cells in the hippocampal CA1 region were arranged closely in the Sham group, loosely and disorderly in the Model group but significantly better in the EPO group. Compared with that in the Model group, the number of apoptotic cells in the EPO group was obviously smaller. The results of Western blotting revealed that the expressions of EPO, p-EPOR, p-SHP2, p-TrKB, p-PI3K, p-ERK1/2 and Bcl-2 rose, while the expressions of P22, P47, Caspase-3, Caspase-9 and Bax significantly declined in the EPO group. Conclusions: EPO can effectively ameliorate the cognitive dysfunction induced by chronic hypoperfusion in VD rats by mediating oxidative stress-related pathways.