外傷性脳損傷
Traumatic brain injury (TBI) is brain trauma caused by significant force to the head. Following TBI, there are both reparative and degenerative mechanisms that lead to an inflammatory environment. Within minutes of injury, pro-inflammatory cytokines are released. The pro-inflammatory cytokine Il-1β is one such cytokine that exacerbates the tissue damage caused by TBI. TBI may cause significant damage to vital components to the brain, including the blood–brain barrier. Il-1β causes DNA fragmentation and apoptosis, and together with TNF-α may cause damage to the blood–brain barrier and infiltration of leukocytes. (). Increased density of activated immune cells have been found in the human brain after concussion.