A new study from John Hopkins University has found behavioral consequences of minimal traumatic brain injury in a study involving mice. Researchers have long recognized that traumatic brain injury is a frequent injury in victims of sports and in motor vehicle collisions and that these individuals often have short and long term physical, cognitive, behavioral and emotional impairments. They have also recognized that routine and extended clinical and laboratory evaluations of mild traumatic brain injury patients often fail to demonstrate clear morphological brain defects despite the fact that these patients frequently suffer from lasting cognitive, behavioral and emotional difficulties. Therefore, the researchers presented a “modified weight drop model” used to deliver a closed head minimal traumatic brain injury to mice, which closely mimics real life injuries and symptoms observed in mild traumatic brain injury patients. The impact force did not produce any structural damage to the mouse’s brain and its surrounding tissue (as confirmed by MRI), no skull fracture, no edema and no evident damage to the blood-brain barrier. Furthermore, the mice showed no abnormal behavior on recovery from the weight drop or any change in other brain function such as reflexes, balance, exploration, strength, locomotor activity and swim speed. The authors were of the opinion that “since our MTBI model does not produce neurological, motor or sensory damage to the mice, it allows the direct evaluation of MTBI sequelae on mice behavior and cognitive abilities.
Using various cognitive and behavioral tests the researchers assessed the short and long term sequelae induced by the model. The results indicated that closed head mild TBI caused profound and long-lasting, irreversible learning and memory impairments, accompanied by a depressive like behavior in mice, that was evident even 90 days post injury. The authors concluded that the results indicated that closed head mild TBI model presented may be useful in the development of novel therapeutic approaches, such as neuro protective agents for mild TBI.
