Does Environmental Enrichment Exposure Prior to Injury Influence Biomarkers Associated with Chronic Stage TBI?

Abstract

Abstract : Environmental Enrichment (EE) is an innovative technique shown to improve cognitive and functional outcomes, and elevate key biomarkers following traumatic brain injury (TBI). Our study was designed to determine if exposure to EE prior to injury is associated with elevated levels of brain-derived neurotrophic factor (BDNF) and other protective biomolecules during the chronic stage of TBI. To examine the effects of EE before injury, adult male rats were exposed to an enriched environment for 15 days followed by a moderate medial prefrontal cortex injury via controlled cortical impact. After recovery, animals were behaviorally tested for 33 days followed by sacrifice to allow for sample collection and analysis. Results indicated that EE applied before TBI did elevate trkB receptor mRNA levels compared to standard housed animals; however BDNF and other biomarker levels during the chronic stage of TBI were not significantly different. The data suggests that EE exposure prior to TBI has neuroprotective tendencies during the chronic stage; however BDNF and other biomarkers associated with improved performance are not elevated to reflect this mechanism during the timeframe examined.