['To reveal the role of Dnmts in the improvement of spatial learning and memory induced by erythropoietin (EPO) in SAMP8 mice.', "The Morris water maze (MWM) was used to assess spatial learning and memory. Mice were administered by intraperitoneal (i.p.) injection of recombinant human EPO and hippocamppi infusion (IH) of 5-aza-2'-deoxycytidine (5-AZA). The expression of genes Dnmt1, Dnmt3a and Dnmt3b in the hippocampus was detected by real-time qPCR. The level of proteins DNMT1, DNMT3A and DNMT3B was measured by Western blotting.", 'Spatial learning and memory in SAMP8 were promoted after i.p. injection of EPO (5000IU/kg/day) and expression of Dnmt3b mRNA and DNMT3B proteins in the hippocampus increased. The improved memory by EPO was blocked after IH 5-AZA.'] Is dNA methylation necessary for erythropoietin to improve spatial learning and memory in SAMP8 mice?