CHRONIC TREATMENT WITH HUMAN RECOMBINANT ERYTHROPOIETIN INCREASES HEMATOCRIT AND IMPROVES WATER MAZE PERFORMANCE IN MICE

Erythropoietin is a glycoprotein produced endogenously in the kidney, which stimulates red blood cell production. We evaluated the effects o f chronic treatment with recombinant human erythropoietin (epoetin alf a: EPO) on the performance of 6-month-old male C57BL/6J mice in a spat ial learning task, the Morris water maze. Mice were treated with eithe r EPO (1.5 U injected SC every other day) or vehicle (PBS also injecte d SC every other day). Results indicated that the treatment had no eff ect on maze performance after 8 weeks, but after 19 weeks the EPO-trea ted mice showed better performance compared to controls as measured by mean distance (centimeters) to reach the goal platform. The improved performance in EPO-treated mice at 19 weeks was accompanied by an incr eased hematocrit. After 32 wk of EPO-treatment, the hematocrit returne d to baseline levels even though the size and density of the red blood cells were increased.