CHANGES IN THE MICROENVIRONMENT AFTER BRAIN INJURY OF VARYING SEVERITY AND RELATION TO FUNCTIONAL OUTCOME

Abstract

This study employs an experimental rodent model capable of measuring cognitive outcome in relation to measurable pathophysiology. After mild and severe fluid percussion injury, the microenvironment of selected brain sub-regions immediately below the injury, especially the cortex, corpus callosum and hippocampus showed most changes. Deeper and further structures such as the cerebellum gave rise to late-onset changes. This was characterized by elevated inflammatory cytokines as well as the increased silver-stained degenerating fibres. Balance and motor coordination as measured on a beam walk task was not sensitive to changes due to mild injury. However, the rotarod task demonstrated immediate impairment after severe injury whilst mild injury showed progressive decrement. Overall, the study revealed severity-dependent changes for acute injury, and novel late-onset findings for mild injury in distal regions suggestiong the development and spread of a biphasic MTBI pathophysiology. The effect of 2 drugs, Edaravone and DAPT, were also investigated.