Edaravone inhibits DNA peroxidation and neuronal cell death in neonatal hypoxic-ischemic encephalopathy model rat

Edaravone Confers Neuroprotective, Anti-inflammatory, and Antioxidant Effects on the Fetal Brain of a Placental-ischemia Mouse Model

Reduced uterine perfusion pressure (RUPP) is a well-established model which mimics many clinical features of preeclampsia (PE). Edaravone is a free radical scavenger with neuroprotective, antioxidant and anti-inflammatory effects against different models of cerebral ischemia. Therefore, we aimed to elucidate the different potential mechanisms through which PE affects fetal brain development using our previously established RUPP-placental ischemia mouse model. In addition, we investigated the neuroprotective effect of edaravone against the RUPP-induced fetal brain development alterations. On gestation day (GD) 13, pregnant mice were divided into four groups; sham (SV), edaravone (SE), RUPP (RV), and RUPP+edaravone (RE). SV and SE groups underwent sham surgeries, however, RV and RE groups were subjected to RUPP surgery via bilateral uterine ligation. Edaravone (3mg/kg) was injected via tail i.v. injection from GD 14-18. The fetal brains from different groups were collected on GD 18 and subjected to further investigations. The results showed that RUPP altered the structure of fetal brain cortex, induced neurodegeneration, increased the expression of the investigated pro-inflammatory markers; TNF-α, IL-6, IL-1β, and MMP-9. RUPP resulted in microglial and astrocyte activation in the fetal brains, in addition to upregulation of Hif-1α and iNOS. Edaravone conferred a neuroprotective effect via alleviating the inflammatory response, restoring the neuronal structure and decreasing oxidative stress in the developing fetal brain. In conclusion, RUPP-placental ischemia mouse model could be a useful tool to further understand the underlying mechanisms of PE-induced child neuronal alterations. Edaravone could be a potential adjuvant therapy during PE to protect the developing fetal brain. The current study investigated the effects of a placenta-induced ischemia mouse model using reduced uterine perfusion pressure (RUPP) surgery on the fetal brain development and the potential neuroprotective effects of the drug edaravone. The study found that the RUPP model caused neurodegeneration and a pro-inflammatory response in the developing fetal brain, as well as hypoxia and oxidative stress. However, maternal injection of edaravone showed a strong ability to protect against these detrimental effects and target multiple pathways associated with neuronal damage. The current study suggests that the RUPP model could be useful for further study of the impact of preeclampsia on fetal brain development and that edaravone may have potential as a therapy for protecting against this damage.

Current Therapies for Neonatal Hypoxic-Ischaemic and Infection-Sensitised Hypoxic-Ischaemic Brain Damage

Neonatal hypoxic-ischaemic brain damage is a leading cause of child mortality and morbidity, including cerebral palsy, epilepsy, and cognitive disabilities. The majority of neonatal hypoxic-ischaemic cases arise as a result of impaired cerebral perfusion to the foetus attributed to uterine, placental, or umbilical cord compromise prior to or during delivery. Bacterial infection is a factor contributing to the damage and is recorded in more than half of preterm births. Exposure to infection exacerbates neuronal hypoxic-ischaemic damage thus leading to a phenomenon called infection-sensitised hypoxic-ischaemic brain injury. Models of neonatal hypoxia-ischaemia (HI) have been developed in different animals. Both human and animal studies show that the developmental stage and the severity of the HI insult affect the selective regional vulnerability of the brain to damage, as well as the subsequent clinical manifestations. Therapeutic hypothermia (TH) is the only clinically approved treatment for neonatal HI. However, the number of HI infants needed to treat with TH for one to be saved from death or disability at age of 18-22 months, is approximately 6-7, which highlights the need for additional or alternative treatments to replace TH or increase its efficiency. In this review we discuss the mechanisms of HI injury to the immature brain and the new experimental treatments studied for neonatal HI and infection-sensitised neonatal HI.

Perinatal hypoxic-ischemic damage: review of the current treatment possibilities

Neonatal hypoxic-ischemic encephalopathy is a disorder with heterogeneous manifestation due to asphyxia during perinatal period. It affects approximately 3-12 children per 1000 live births and cause death of 1 million neonates worldwide per year. Besides, motor disabilities, seizures, impaired muscle tone and epilepsy are few of the consequences of hypoxic-ischemic encephalopathy. Despite an extensive research effort regarding various treatment strategies, therapeutic hypothermia with intensive care unit supportive treatment remains the only approved method for neonates who have suffered from moderate to severe hypoxic-ischemic encephalopathy. However, these protocols are only partially effective given that many infants still suffer from severe brain damage. Thus, further research to systematically test promising neuroprotective treatments in combination with hypothermia is essential. In this review, we discussed the pathophysiology of hypoxic-ischemic encephalopathy and delved into different promising treatment modalities, such as melatonin and erythropoietin. However, preclinical studies and clinical trials are still needed to further elucidate the mechanisms of action of these modalities.

Free radicals and neonatal encephalopathy: mechanisms of injury, biomarkers, and antioxidant treatment perspectives

Neonatal encephalopathy (NE), most commonly a result of the disruption of cerebral oxygen delivery, is the leading cause of neurologic disability in term neonates. Given the key role of free radicals in brain injury development following hypoxia-ischemia-reperfusion, several oxidative biomarkers have been explored in preclinical and clinical models of NE. Among these, antioxidant enzyme activity, uric acid excretion, nitric oxide, malondialdehyde, and non-protein-bound iron have shown promising results as possible predictors of NE severity and outcome. Owing to high costs and technical complexity, however, their routine use in clinical practice is still limited. Several strategies aimed at reducing free radical production or upregulating physiological scavengers have been proposed for NE. Room-air resuscitation has proved to reduce oxidative stress following perinatal asphyxia and is now universally adopted. A number of medications endowed with antioxidant properties, such as melatonin, erythropoietin, allopurinol, or N-acetylcysteine, have also shown potential neuroprotective effects in perinatal asphyxia; nevertheless, further evidence is needed before these antioxidant approaches could be implemented as standard care.

DNA damage accumulates and responses are engaged in human ALS brain and spinal motor neurons and DNA repair is activatable in iPSC-derived motor neurons with SOD1 mutations

DNA damage is implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). However, relationships between DNA damage accumulation, DNA damage response (DDR), and upper and lower motor neuron vulnerability in human ALS are unclear; furthermore, it is unknown whether epigenetic silencing of DNA repair pathways contributes to ALS pathogenesis. We tested the hypotheses that DNA damage accumulates in ALS motor neurons along with diminished DDR, and that DNA repair genes undergo hypermethylation. Human postmortem CNS tissue was obtained from ALS cases (N = 34) and age-matched controls without neurologic disease (N = 15). Compared to age-matched controls, abasic sites accumulated in genomic DNA of ALS motor cortex and laser capture microdissection-acquired spinal motor neurons but not in motor neuron mitochondrial DNA. By immunohistochemistry, DNA damage accumulated significantly in upper and lower motor neurons in ALS cases as single-stranded DNA and 8-hydroxy-deoxyguanosine (OHdG) compared to age-matched controls. Significant DDR was engaged in ALS motor neurons as evidenced by accumulation of c-Abl, nuclear BRCA1, and ATM activation. DNA damage and DDR were present in motor neurons at pre-attritional stages and throughout the somatodendritic attritional stages of neurodegeneration. Motor neurons with DNA damage were also positive for activated p53 and cleaved caspase-3. Gene-specific promoter DNA methylation pyrosequencing identified the DNA repair genes Ogg1, Apex1, Pnkp and Aptx as hypomethylated in ALS. In human induced-pluripotent stem cell (iPSC)-derived motor neurons with familial ALS SOD1 mutations, DNA repair capacity was similar to isogenic control motor neurons. Our results show that vulnerable neurons in human ALS accumulate DNA damage, and contrary to our hypothesis, strongly activate and mobilize response effectors and DNA repair genes. This DDR in ALS motor neurons involves recruitment of c-Abl and BRCA1 to the nucleus in vivo, and repair of DNA double-strand breaks in human ALS motor neurons with SOD1 mutations in cell culture.

Intravenous Edaravone plus Therapeutic Hypothermia Offers Limited Neuroprotection in the Hypoxic-Ischaemic Newborn Piglet

BACKGROUND

Therapeutic hypothermia (TH) is a standard therapy for neonatal hypoxic-ischaemic encephalopathy. One potential additional therapy is the free radical scavenger edaravone (EV; 3-methyl-1-phenyl-2-pyrazolin-5-one).

OBJECTIVES AND METHODS

This study aimed to compare the neuroprotective effects of edaravone plus therapeutic hypothermia (TH + EV) with those of TH alone after a hypoxic-ischaemic insult in the newborn piglet. Anaesthetized piglets were subjected to 40 min of hypoxia (3-5% inspired oxygen), and cerebral ischaemia was assessed using cerebral blood volume. Body temperature was maintained at 39.0 ± 0.5°C in the normothermia group (NT, n = 8) and at 33.5 ± 0.5°C (24 h after the insult) in the TH (n = 7) and TH + EV (3 mg/kg intravenous every 12 h for 3 days after the insult; n = 6) groups under mechanical ventilation.

RESULTS

Five days after the insult, the mean (standard deviation) neurological scores were 10.9 (5.7) in the NT group, 17.0 (0.4) in the TH group (p = 0.025 vs. NT), and 15.0 (3.9) in the TH + EV group. The histopathological score of the TH + EV group showed no significant improvement compared with that of the other groups.

CONCLUSION

TH + EV had no additive neuroprotective effects after hypoxia-ischaemia in neurological and histopathological assessments.

Effects of Therapeutic Hypothermia Combined with Other Neuroprotective Strategies on Ischemic Stroke: Review of Evidence

Ischemic stroke is a major cause of death and disability globally, and its incidence is increasing. The only treatment approved by the US Food and Drug Administration for acute ischemic stroke is thrombolytic treatment with recombinant tissue plasminogen activator. As an alternative, therapeutic hypothermia has shown excellent potential in preclinical and small clinical studies, but it has largely failed in large clinical studies. This has led clinicians to explore the combination of therapeutic hypothermia with other neuroprotective strategies. This review examines preclinical and clinical progress towards developing highly effective combination therapy involving hypothermia for stroke patients.

Edaravone attenuates neuronal apoptosis in hypoxic-ischemic brain damage rat model via suppression of TRAIL signaling pathway

BACKGROUND AND OBJECTIVES

Edaravone is a new type of oxygen free radical scavenger and able to attenuate various brain damage including hypoxic-ischemic brain damage (HIBD). This study was aimed at investigating the neuroprotective mechanism of edaravone in rat hypoxic-ischemic brain damage model and its correlation with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling pathway.

MATERIALS AND METHODS

75 seven-day-old Sprague-Dawley neonatal rats were equally divided into three groups: sham-operated group (sham), HIBD group and HIBD rats injected with edaravone (HIBD + EDA) group. Neurological severity and space cognitive ability of rats in each group were evaluated using Longa neurological severity score and Morris water maze testing. TUNEL assay and flow cytometry were used to determine brain cell apoptosis. Western blot was used to estimate the expression level of death receptor-5 (DR5), Fas-associated protein with death domain (FADD), caspase 8, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax). In addition, immunofluorescence was performed to detect caspase 3.

RESULTS

Edaravone reduced neurofunctional damage caused by HIBD and improved the cognitive capability of rats. The above experiment results suggested that edaravone could down-regulate the expression of active caspase 3 protein, thereby relieving neuronal apoptosis.

CONCLUSION

Taken together, edaravone could attenuate neuronal apoptosis in rat hypoxic-ischemic brain damage model via suppression of TRAIL signaling pathway, which also suggested that edaravone might be an effective therapeutic strategy for HIBD clinical treatment.

Possible Mechanism of Therapeutic Effect of 3-Methyl-1-phenyl-2-pyrazolin-5-one and Bone Marrow Stromal Cells Combination Treatment in Rat Ischemic Stroke Model

Background:

The functional improvement following bone marrow stromal cells (BMSCs) transplantation after stroke is directly related to the number of engrafted cells and neurogenesis in the injured brain. Here, we tried to evaluate whether 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), a free radical scavenger, might influence BMSCs migration to ischemic brain, which could promote neurogenesis and thereby enhance treatment effects after stroke.

Methods:

Rat transient middle cerebral artery occlusion (MCAO) model was established. Two separate MCAO groups were administered with either MCI-186 or phosphate-buffered saline (PBS) solution to evaluate the expression of stromal cell-derived factor-1 (SDF-1) in ischemic brain, and compared to that in sham group (n = 5/group/time point[at 1, 3, and 7 days after operation]). The content of chemokine receptor-4 (CXCR4, a main receptor of SDF-1) at 7 days after operation was also observed on cultured BMSCs. Another four MCAO groups were intravenously administered with either PBS, MCI-186, BMSCs (2 × 10⁶), or a combination of MCI-186 and BMSCs (n = 10/group). 5-bromo-2-deoxyuridine (BrdU) and Nestin double-immunofluorescence staining was performed to identify the engrafted BMSCs and neuronal differentiation. Adhesive-removal test and foot-fault evaluation were used to test the neurological outcome.

Results:

MCI-186 upregulated the expression of SDF-1 in ischemic brain and CXCR4 content in BMSCs was enhanced after hypoxic stimulation. When MCAO rats were treated with either MCI-186, BMSCs, or a combination of MCI-186 and BMSCs, the neurologic function was obviously recovered as compared to PBS control group (P < 0.01 or 0.05, respectively). Combination therapy represented a further restoration, increased the number of BMSCs and Nestin⁺ cells in ischemic brain as compared with BMSCs monotherapy (P < 0.01). The number of engrafted-BMSCs was correlated with the density of neuronal cells in ischemic brain (r = 0.72, P < 0.01) and the improvement of foot-fault (r = 0.70, P < 0.01).

Conclusion:

MCI-186 might promote BMSCs migration to the ischemic brain, amplify the neurogenesis, and improve the effects of cell therapy.

Oxidative Stress in Hypoxic-Ischemic Encephalopathy: Molecular Mechanisms and Therapeutic Strategies

Hypoxic-ischemic encephalopathy (HIE) is one of the leading causes of morbidity and mortality in neonates. Because of high concentrations of sensitive immature cells, metal-catalyzed free radicals, non-saturated fatty acids, and low concentrations of antioxidant enzymes, the brain requires high levels of oxygen supply and is, thus, extremely sensitive to hypoxia. Strong evidence indicates that oxidative stress plays an important role in pathogenesis and progression. Following hypoxia and ischemia, reactive oxygen species (ROS) production rapidly increases and overwhelms antioxidant defenses. A large excess of ROS will directly modify or degenerate cellular macromolecules, such as membranes, proteins, lipids, and DNA, and lead to a cascading inflammatory response, and protease secretion. These derivatives are involved in a complex interplay of multiple pathways (e.g., inflammation, apoptosis, autophagy, and necrosis) which finally lead to brain injury. In this review, we highlight the molecular mechanism for oxidative stress in HIE, summarize current research on therapeutic strategies utilized in combating oxidative stress, and try to explore novel potential clinical approaches.

Protective effect of Edaravone against hypoxia-induced cytotoxicity in osteoblasts MC3T3-E1 cells

Edaravone is a newly developed clinical medicine for the treatment of acute cerebral infarction. Reduced blood supply to bones (hypoxia) has been involved in the pathological development of osteoporosis. In this study, we investigated the effect of Edaravone and its latent mechanism on hypoxia-induced cell toxicity in MC3T3-E1 cells. Cell viability was determined by the 3-(4,5-dimethyl-thiazol-2yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Intracellular reactive oxygen species (ROS) and nitric oxide (NO) were determined by the fluorescence dyes 2',7'-dichlorofluorescein diacetate (DCFH-DA) and 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate (DAF-FM DA), respectively. mRNA and proteins were determined by real-time polymerase chain reaction and Western blot analysis, respectively. Edaravone significantly restored the hypoxia-induced reduction of MC3T3-E1 cell viability and inhibited lactate dehydrogenase release. In addition, we found that Edaravone inhibits the generation of ROS and NO. Hoechst staining results indicated that the nuclear condensation characteristic of apoptosis was increased in MC3T3-E1 cells after hypoxia exposure, which was significantly suppressed by Edaravone treatment. Mechanistically, we found that Edaravone markedly reduced the expression of cleaved caspase-3 and blunted the release of cytochrome c. These findings strongly suggested that Edaravone suppresses hypoxia-induced cytotoxicity in MC3T3-E1 cells. The pleiotropic effects of Edaravone on hypoxia exposure in osteoblasts suggest potential antiosteoporosis mechanisms of Edaravone.

Neuroprotective Effects of Thymoquinone on the Hippocampus in a Rat Model of Traumatic Brain Injury

BACKGROUND

Traumatic brain injury is a leading cause of morbidity and mortality worldwide. We evaluated the neuroprotective effects of thymoquinone (TQ) in a rat model of traumatic brain injury by using biochemical and histopathologic methods for the first time.

MATERIALS AND METHODS

Twenty-four rats were divided into sham (n = 8), trauma (n = 8), and TQ-treated (n = 8) groups. A moderate degree of head trauma was induced with the use of Feeney's falling weight technique, and TQ (5 mg/kg/day) was administered to the TQ-treated group for 7 days. All animals were killed after cardiac perfusion. Brain tissues were extracted immediately after perfusion without damaging the tissues. Biochemical procedures were performed with the serum, and a histopathologic evaluation was performed on the brain tissues. Biochemical experiments included malondialdehyde (MDA), reduced and oxidized coenzyme Q10 analysis, DNA isolation and hydroylazation, and glutathione peroxidase, and superoxide dismutase analyses.

RESULTS

Neuron density in contralateral hippocampal regions (CA1, CA2-3, and CA4) 7 days after the trauma decreased significantly in the trauma and TQ-treated groups, compared with that in the control group. Neuron densities in contralateral hippocampal regions (CA1, CA2-3, and CA4) were greater in the TQ-treated group than in the trauma group. TQ did not increase superoxide dismutase or glutathione peroxidase antioxidant levels. However, TQ decreased the MDA levels.

CONCLUSIONS

These results indicate that TQ has a healing effect on neural cells after head injury and this effect is mediated by decreasing MDA levels in the nuclei and mitochondrial membrane of neurons.

Neuroprotective Strategies after Neonatal Hypoxic Ischemic Encephalopathy

Neonatal hypoxic ischemic encephalopathy (HIE) is a devastating disease that primarily causes neuronal and white matter injury and is among the leading cause of death among infants. Currently there are no well-established treatments; thus, it is important to understand the pathophysiology of the disease and elucidate complications that are creating a gap between basic science and clinical translation. In the development of neuroprotective strategies and translation of experimental results in HIE, there are many limitations and challenges to master based on an appropriate study design, drug delivery properties, dosage, and use in neonates. We will identify understudied targets after HIE, as well as neuroprotective molecules that bring hope to future treatments such as melatonin, topiramate, xenon, interferon-beta, stem cell transplantation. This review will also discuss some of the most recent trials being conducted in the clinical setting and evaluate what directions are needed in the future.

Protective effect of edaravone against manganese-induced toxicity in cultured rat astrocytes

Manganese (Mn), a trace metal, is essential for maintaining the normal regulation of many biochemical and cellular processes. However, accumulation of Mn due to excessive environmental exposure leads to neurological impairment, referred to as manganism. Edaravone (EDA) is a potent free radical scavenger that has been clinically shown to reduce the neuronal injury after cerebral ischemia. In the present study, we aimed to examine the protective effects of EDA against Mn toxicity in astrocyte cultures. Astrocyte cultures were prepared from cerebral cortices of newborn Sprague-Dawley rats. The experiments were performed between 16 and 18 days of cultures. Astrocytes were treated in DMEM medium containing Mn (1-1000μM) for 24h to test Mn toxicity. In order to assess the effect of EDA, cells were pre-treated with different doses of EDA (10, 100 and 1000μM) 6h before Mn treatment. Cell viability (MTT), apoptotic cell death (Hoechst test) and lipid peroxide levels were evaluated in cultures. Our results showed that Mn significantly and dose-dependently reduced cell viability in astrocyte cultures. The apoptotic cell death and lipid peroxides were significantly higher in Mn treated cultures. Treatment of astrocytes with EDA successfully suppressed oxidative stress and cell death due to Mn exposure. The findings of the present study suggest that Mn cytotoxicity is mainly associated with ROS generation and apoptotic cell death. Besides, EDA may have beneficial effects against Mn toxicity. However, further studies are needed to elucidate the molecular mechanisms underlying protective effect of EDA.

Edaravone protects human peripheral blood lymphocytes from γ-irradiation-induced apoptosis and DNA damage

Radiation-induced cellular injury is attributed primarily to the harmful effects of free radicals, which play a key role in irradiation-induced apoptosis. In this study, we investigated the radioprotective efficacy of edaravone, a licensed clinical drug and a powerful free radical scavenger that has been tested against γ-irradiation-induced cellular damage in cultured human peripheral blood lymphocytes in studies of various diseases. Edaravone was pre-incubated with lymphocytes for 2 h prior to γ-irradiation. It was found that pretreatment with edaravone increased cell viability and inhibited generation of γ-radiation-induced reactive oxygen species (ROS) in lymphocytes exposed to 3 Gy γ-radiation. In addition, γ-radiation decreased antioxidant enzymatic activity, such as superoxide dismutase and glutathione peroxidase, as well as the level of reduced glutathione. Conversely, treatment with 100 μM edaravone prior to irradiation improved antioxidant enzyme activity and increased reduced glutathione levels in irradiated lymphocytes. Importantly, we also report that edaravone reduced γ-irradiation-induced apoptosis through downregulation of Bax, upregulation of Bcl-2, and consequent reduction of the Bax:Bcl-2 ratio. The current study shows edaravone to be an effective radioprotector against γ-irradiation-induced cellular damage in lymphocytes in vitro. Finally, edaravone pretreatment significantly reduced DNA damage in γ-irradiated lymphocytes, as measured by comet assay (% tail DNA, tail length, tail moment, and olive tail moment) (p < 0.05). Thus, the current study indicates that edaravone offers protection from radiation-induced cytogenetic alterations.

NAP prevents acute cerebral oxidative stress and protects against long-term brain injury and cognitive impairment in a model of neonatal hypoxia-ischemia

Hypoxia-ischemia (HI) is a common cause of neonatal brain damage with lifelong morbidities in which current therapies are limited. In this study, we investigated the effect of neuropeptide NAP (NAPVSIPQ) on early cerebral oxidative stress, long-term neurological function and brain injury after neonatal HI. Seven-day-old rat pups were subjected to an HI model by applying a unilateral carotid artery occlusion and systemic hypoxia. The animals were randomly assigned to groups receiving an intraperitoneal injection of NAP (3 μg/g) or vehicle immediately (0 h) and 24 h after HI. Brain DNA damage, lipid peroxidation and reduced glutathione (GSH) content were determined 24 h after the last NAP injection. Cognitive impairment was assessed on postnatal day 60 using the spatial version of the Morris water maze learning task. Next, the animals were euthanized to assess the cerebral hemispheric volume using the Cavalieri principle associated with the counting point method. We observed that NAP prevented the acute HI-induced DNA and lipid membrane damage and also recovered the GSH levels in the injured hemisphere of the HI rat pups. Further, NAP was able to prevent impairments in learning and long-term spatial memory and to significantly reduce brain damage up to 7 weeks following the neonatal HI injury. Our findings demonstrate that NAP confers potent neuroprotection from acute brain oxidative stress, long-term cognitive impairment and brain lesions induced by neonatal HI through, at least in part, the modulation of the glutathione-mediated antioxidant system.

Edaravone protects against apoptotic neuronal cell death and improves cerebral function after traumatic brain injury in rats

Edaravone is a novel free radical scavenger used clinically in patients with acute cerebral infarction; however, it has not been assessed in traumatic brain injury (TBI). We investigated the effects of edaravone on cerebral function and morphology following TBI. Rats received TBI with a pneumatic controlled injury device. Edaravone (3 mg/kg) or physiological saline was administered intravenously following TBI. 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.