The Effects of Aerobic Exercises on Memory, Cerebral Edema, and Extracellular Neuronal Discharge in an Experimental Model of Traumatic Brain Injury: The Role of BDNF Expression

Abstract

Background: Traumatic brain injury (TBI) remains a primary cause of mortality and is a significant contributor to various impairments, including somatosensory and cognitive deficits. The prevention and management of injuries require regular daily exercise. In this research, we examined the impact of eight weeks of aerobic exercise on neurological outcomes, brain water content (BWC), blood-brain barrier (BBB) permeability, electrophysiological characteristics, and concentrations of brain-derived neurotrophic factor (BDNF) in an experimental model of TBI. Methods: Sixty-four male Wistar rats were divided into four groups: Control, Training, TBI, and Training-TBI. TBI was induced using the Marmarou method. After TBI induction, eight weeks of aerobic exercise were performed using a five-line animal treadmill. Then, the rats’ memory and learning were assessed using the Morris water maze. Electrodes were implanted in the skulls of anesthetized rats for single-unit recording. Neurological scores, BWC, BBB permeability, and cerebral tissue BDNF concentrations were measured 48 hours after exercise. Statistical analysis was conducted using one-way ANOVA, followed by Tukey’s post hoc test for multiple comparisons. P values<0.05 were considered statistically significant. Results: Aerobic exercise significantly reversed the decrement of neurological scores, the neuronal firing rate of the hippocampus, increments of BWC, cognition deficits, and cerebral tissue Evans blue concentration after TBI compared with control. It also increased cerebral tissue BDNF, which had significantly decreased in TBI. Conclusion: Our results suggest that through BDNF increment, aerobic exercise exerts neuroprotective effects on memory impairment and the decrement of neuronal firing rate caused by TBI.