This efficacy study was designed to investigate traumatic brain injury (TBI) in rats treated with delayed erythropoietin (EPO) administered in a single dose compared with a triple dose.
Young adult male Wistar rats were randomly divided into the following groups: 1) sham group (6 animals); 2) TBI/saline group (6 animals); 3) TBI/EPO×1 group (6 animals); and 4) TBI/EPO×3 group (7 animals). Traumatic brain injury was induced by controlled cortical impact over the left parietal cortex. Erythropoietin (5000 U/kg) or saline was administered intraperitoneally on Day 1 (EPO×1 group) or on Days 1, 2, and 3 (EPO×3 group) postinjury. Neurological function was assessed using a modified neurological severity score, foot-fault, and Morris water maze tests. Animals were killed 35 days after injury and brain sections were stained for immunohistochemistry.
Compared with the saline treatment, EPO treatment in both the EPO×1 and EPO×3 groups significantly reduced hippocampal cell loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, and significantly improved neurological functional outcome. The EPO×3 group exhibited significantly improved functional and histological outcomes compared with the EPO×1 group.
These data demonstrate that delayed posttraumatic administration of EPO significantly improved histological and long-term functional outcomes in rats after TBI. The triple doses of delayed EPO treatment produced better histological and functional outcomes in rats, although a single dose provided substantial benefits compared with saline treatment.