BDNF expression increases without changes in play behavior following concussion in juvenile rats (Rattus Norvegicus).

PURPOSE: Young children have a high risk of concussion or mild traumatic brain injury (mTBI). Children often appear healthy soon after mTBI, but some have pervasive cognitive and/or motor impairments. Understanding underlying mechanisms recruited after concussion may help for return to play protocols and mitigating what might be lifelong impairments.

METHODS: We investigated molecular and behavioral changes in a rat model of childhood concussion. Rats received an injury or sham procedure at an age approximately equivalent to the human period of early childhood. Social play was analyzed for behavioral differences. Tissue from the right motor cortex (impacted), left motor cortex, and medial prefrontal cortex were analyzed for brain derived neurotrophic factor (BDNF) protein.

RESULTS: Play behavior was not significantly different between conditions. BDNF levels were much higher in both the right and left motor cortices of the mTBI group compared to medial prefrontal cortex, which is relatively remote from the impact site, within the mTBI group and all tissue collected from the sham group.

CONCLUSIONS: There is ongoing plastic change at the cellular level in both the impacted area and the well-connected contralateral area after a concussion, suggesting compensatory mechanisms after injury are still at play.