Cellular and Molecular Pathophysiology of Traumatic Brain Injury: What Have We Learned So Far?

SIMPLE SUMMARY: Traumatic brain injury (TBI) is a catastrophic event to the health and life of its sufferers, and it also affects their relatives. In addition to the underlying complications of the resulting condition of affected individuals, there are substantial implications for health and social security systems, since the productive capacity of people who suffer the consequences of a TBI is greatly limited. In this sense, it is essential that studies aimed at a better understanding of the physiological changes resulting from a TBI be carried out. Our work aims to review the main factors related to the alteration of injured brain tissue after TBI, such as inflammatory response, excitotoxicity, and oxidative stress. The adequate understanding of the phenomena resulting from TBI can help improve the care, rehabilitation process and quality of life of the affected people in addition to reducing the associated economic impact. ABSTRACT: Traumatic brain injury (TBI) is one of the leading causes of long-lasting morbidity and mortality worldwide, being a devastating condition related to the impairment of the nervous system after an external traumatic event resulting in transitory or permanent functional disability, with a significant burden to the healthcare system. Harmful events underlying TBI can be classified into two sequential stages, primary and secondary, which are both associated with breakdown of the tissue homeostasis due to impairment of the blood–brain barrier, osmotic imbalance, inflammatory processes, oxidative stress, excitotoxicity, and apoptotic cell death, ultimately resulting in a loss of tissue functionality. The present study provides an updated review concerning the roles of brain edema, inflammation, excitotoxicity, and oxidative stress on brain changes resulting from a TBI. The proper characterization of the phenomena resulting from TBI can contribute to the improvement of care, rehabilitation and quality of life of the affected people.