Histological and immunohistochemical study of experimentallyinduced concussion on young rats’ frontal cortex andthe possible protective role of erythropoietin hormonesupplementation

IntroductionClosed-head concussive injury is one of the most common causes of traumatic braininjury. Multiple concussions, especially in children, can result in cumulative damageand increased risk for neurodegenerative diseases in later life.Aim of the workThe aim of the work was to clarify the effect of repeated concussions on the frontalcortex architecture and to identify a new protective therapy that decreases the braininsult caused by repeated concussions.Materials and methodsTwenty male albino rats 17–19 days old were divided into four groups: group I(control group) included five rats. The remaining rats were subjected to repeatedhead concussions for 3 successive days and then divided equally into the followinggroups: in group II (concussion group), animals were sacrificed 24 h after the lastconcussion; in group III (recovery group), rats were sacrificed 10 days after the lastconcussion; and in group IV (treated group), rats received an erythropoietin (EPO)injection for 3 successive days after the last concussion and were then sacrificed.The frontal cortex was examined using histological and immunohistochemicaltechniques.ResultsIn the present study, it was found that after 24 h of repeated concussions, subpialcellular infiltration, edema, and congested blood vessels were detected. The frontalcortex neurons showed degenerative changes. A significant decrease in glialfibrillar acid protein (GFAP) and synaptophysin (SYN) immunoreactivity was alsodetected. The recovery group showed hypercellularity of the frontal cortex. Someneurons still showed degenerative changes. A significant increase in GFAP and SYNimmunoreactivity was detected. In the EPO-treated group, neurons were more or lessnormal. A significant decrease in GFAP immunoreactivity with a significant increase inSYN reactivity was detected compared with the recovery group.ConclusionConcussion induced degenerative changes in neurons, neuroglia, and synapses.Recovery decreased degenerative changes with marked gliosis. Treatment with EPOimproved degeneration, gliosis, and synapses.