Question: What is the role of edaravone in traumatic brain injury?

Context:
 The edaravone-treated animals also exhibited higher rCBF in the contralateral hemisphere compared with that seen in -vehicle-treated animals. It is suggested that edaravone reduces neuronal damage by scavenging reactive oxygen species (ROS) and by maintaining intact the autoregulation of the cerebral vasculature.
Edaravone administration after CCI resulted in a significant reduction in the injury volume and oxidative stress, particularly at the 3-hour time point. Moreover, the greatest decrease in O2 (∙-) levels was observed when edaravone was administered 3 hours following CCI. These findings suggest that edaravone could prove clinically useful to ameliorate the devastating effects of TBI.
Edaravone significantly suppressed axonal injury and oxidative stress in the cortex, corpus callosum, and hippocampus 24h after injury. 
These results suggest that edaravone protects against memory deficits following TBI and that this protection is mediated by suppression of TAI and oxidative stress.
Concordantly, edaravone has been found to have neuroprotective effects in a number of animal models of disease, including stroke, spinal cord injury, traumatic brain injury, neurodegenerative diseases and brain tumors. 
Free-radical scavenger edaravone treatment confers neuroprotection against traumatic brain injury in rats.
Edaravone treatment significantly decreased hippocampal CA3 neuron loss, reduced oxidative stress, and decreased neuronal programmed cell death compared to vehicle treatment. 
Lastly, edaravone treatment significantly reduced the presence of inflammatory cytokines, cerebral edema, blood-brain barrier (BBB) permeability, and, importantly, neurological deficits following TBI. Our results suggest that edaravone exerts a neuroprotective effect in the rat model of TBI. The likely mechanism is via inhibiting oxidative stress, leading to a decreased inflammatory response and glial activation, and thereby reducing neuronal death and improving neurological function.
After treatment with edaravone, the degree of morphological injury, p-ERK1/2 level and number of apoptotic neurons decreased, latent period to find the safety platform was significantly shortened (in low-dose edaravone treatment group, p-ERK1/2 expression level at 6, 24, 48 hours was 2.46 + or - 0.22, 4.00 + or - 0.84, 2.38 + or - 0.32, and in high-dose edaravone treatment group was 1.67 + or - 0.15, 1.86 + or - 0.38, 1.27 + or - 0.28; in low-dose edaravone treatment group, the apoptotic cells at 6, 24, 48, 72 hours was 5.20 + or - 1.23, 7.10 + or - 1.72, 9.54 + or - 1.36, 14.12 + or - 3.19, and in high-dose edaravone treatment group was 3.40 + or - 0.49 , 4.39 + or - 0.73, 5.02 + or - 1.12, 8.78 + or - 2.16; in low-dose edaravone treatment group, latent period to find the safety platform at 7-10 days was 94.8 + or - 22.8, 65.2 + or - 19.0, 62.0 + or - 16.7, 59.5 + or - 15.6, and in high-dose edaravone treatment group it was 81.5 + or - 20.7, 55.4 + or - 18.5, 40.0 + or - 12.3, 32.2 + or - 11.0, all P<0.05). High-dose edaravone showed a better effect (all P<0.05).
 Edaravone gives good therapeutic effect on severe TBI, and the molecular mechanism is related to attenuation of ERK1/2 pathway and neuronal apoptosis following severe brain trauma.
Numbers of 8-OHdG-, 4-HNE-, and ssDNA-positive cells around the damaged area after TBI were significantly decreased in the edaravone group compared with the saline group (P < 0.01). There was a significant increase in neuronal cell number and improvement in cerebral dysfunction after TBI in the edaravone group compared with the saline group (P < 0.01). Edaravone administration following TBI inhibited free radical-induced neuronal degeneration and apoptotic cell death around the damaged area. In summary, edaravone treatment improved cerebral dysfunction following TBI, suggesting its potential as an effective clinical therapy.
Edaravone administration inhibited production of free radicals known to induce neuronal degeneration and cell death after brain injury, and protected nestin-positive cells, including NSCs, with the potential to differentiate into neurons and glia around the area damaged by TBI.
Under specific experimental conditions, edaravone minimized traumatic brain injury by functioning as a synthetic antioxidant. 
Thus, edaravone can scavenge OR- and significantly reduce levels of these radicals in TBI patients.

Answer: Edaravone, a free radical scavenger, has been shown to have neuroprotective effects after traumatic brain injury. In animal models, edaravone has been shown to reduce neuronal damage by scavenging reactive oxygen species (ROS), maintain intact the autoregulation of the cerebral vasculature, decrease neuronal loss, reduce programmed cell death, the presence of inflammatory cytokines, cerebral edema, and blood-brain barrier (BBB) permeability. Edaravone also protects against neurological deficits and memory deficits following traumatic brain injury.