Effect of erythropoietin on cognitive function in rats with traumatic brain injury

Objective To evaluate the effect of erythropoietin (EPO) on cognitive function in rats with traumatic brain injury (TBI) and investigate its mechanisms. Methods Forty-eight SD rats were equally randomized into control, sham-operated, TBI and EPO+TBI groups. TBI models were established in the later 2 groups by operation and hydraulic shock. Sham-operated group received the operation only. The EPO+TBI group was injected with EPO immediately after the success of model making; the other groups were injected with saline at the same time. On the 30th d of injury, Morris water maze was employed to evaluate the cognitive function of the rats and the expression of brain-derived growth factor (BDNF) was detected by immunohistochemistry. Results In the navigation experiment, the latent period (the rats on founding the platform) in the control and sham-operated groups was significantly shorter than that in the other 2 groups (P<0.05); that in the TBI group was statistically longer than that in the EPO+TBI group (P<0.05). In the space searching experiment, the swimming times of the rats in each quadrant were significantly different (P<0.05): the control and sham-operated groups were the longest and the TBI group was the shortest of all the 4 groups. Immunohistochemistry showed that the expression of BDNF in the EPO+TBI group was significantly higher than that in the other 3 groups (P< 0.05). Conclusion TBI can damage cognitive function of the rats, while exogenous EPO may improve their memory abilities by up-regulating the expression of BDNF. Key words: Erythropoietin; Traumatic brain injury; Cognitive function; BDNF