Induction Of Traumatic Brain Injury Research Articles

The nongenomic neuroprotective effects of estrogen, E2-BSA, and G1 following traumatic brain injury: PI3K/Akt and histopathological study.

Studies suggest that both genomic and nongenomic pathways are involved in mediating the salutary effects of steroids following traumatic brain injury (TBI). This study investigated the nongenomic effects of 17β-estradiol (E2) mediated by the PI3K/p-Akt pathway after TBI. Ovariectomized rats were apportioned to E2, E2-BSA (E2 conjugated to bovine serum albumin), G1 [G-protein-coupled estrogen receptor agonist (GPER)] or their vehicle was injected following TBI, whereas ICI (classical estrogen receptor antagonist), G15 (GPER antagonist), ICI+G15, and their vehicles were injected before the induction of TBI and injection of drugs. Diffuse TBI was induced by the Marmarou model. Evans blue (EBC, 5 h), brain water contents (BWC), histopathological changes, and brain PI3K and p-Akt protein expressions were measured 24 h after TBI. The veterinary comma scale (VCS) was assessed before and at different times after TBI. The results showed a reduction in BWC and EBC and increased VCS in the E2, E2-BSA, and G1 groups. Also, E2, E2-BSA, and G1 reduced brain edema, inflammation, and apoptosis. The ICI and G15 inhibited the beneficial effects of E2, E2-BSA, and G1 on these parameters. All drugs, following TBI, prevented the reduction of brain PI3K/p-Akt expression. The individual or combined use of ICI and G15 eliminated the beneficial effects of E2, E2-BSA, and G1 on PI3K/p-Akt expressions. These findings indicated that PI3K/p-Akt pathway plays a critical role in mediating the salutary effects of estradiol on histopathological changes and neurological outcomes following TBI, suggesting that GPER and classic ERs are involved in regulating the expression of PI3K/p-Akt.

Therapeutic benefits of quercetin in traumatic brain injury model exposed to cigarette smoke

Scientific evidences reported the deleterious effect of cigarette smoking or passive smoking on brain health particularly cognitive functions, blood–brain barrier (BBB) permeability, up-regulation of inflammatory cascades, and depletion of the antioxidant system. These combined effects become more progressive in the events of stroke, traumatic brain injury (TBI), and many other neurodegenerative diseases. In the current study, we investigated the long-term administered therapeutic potential of quercetin in ameliorating the deleterious neurobiological consequences of chronic tobacco smoke exposure in TBI mice. After exposure to 21 days of cigarette smoke and treatment with 50 mg/kg of quercetin, C57BL/6 mice were challenged for the induction of TBI by the weight drop method. Subsequently, a battery of behavioral tests and immunohistochemical analyses revealed the beneficial effect of quercetin on the locomotive and cognitive function of TBI + smoked group mice (p < 0.05 vs control sham). Immunohistochemistry analysis (Nrf2, HO-1, NFkB, caspase 3) demonstrated a marked protection after 21 days of quercetin treatment in the chronic tobacco smoking group possibly by up-regulation of antioxidant pathways, and decreased apoptosis. In conclusion, our findings support the therapeutic effectiveness of quercetin in partly protecting the central neurological functions that become aberrantly impaired in combined habitual cigarette-smoking individuals impacted with TBI.

Carvacrol decreases blood–brain barrier permeability post-diffuse traumatic brain injury in rats

Previously, we showed that Satureja Khuzestanica Jamzad essential oil (SKEO) and its major component, carvacrol (CAR), 5-isopropyl-2-methylphenol, has anti-inflammatory, anti-apoptotic, and anti-edematous properties after experimental traumatic brain injury (TBI) in rats. CAR, predominantly found in Lamiaceae family (Satureja and Oregano), is lipophilic, allowing diffusion across the blood–brain barrier (BBB). These experiments test the hypothesis that acute treatment with CAR after TBI can attenuate oxidative stress and BBB permeability associated with CAR’s anti-edematous traits. Rats were divided into six groups and injured using Marmarou weight drop: Sham, TBI, TBI + Vehicle, TBI + CAR (100 and 200 mg/kg) and CAR200-naive treated rats. Intraperitoneal injection of vehicle or CAR was administered thirty minutes after TBI induction. 24 h post-injury, brain edema, BBB permeability, BBB-related protein levels, and oxidative capacity were measured. Data showed CAR 200 mg/kg treatment decreased brain edema and prevented BBB permeability. CAR200 decreased malondialdehyde (MDA) and reactive oxygen species (ROS) and increased superoxide dismutase (SOD) and total antioxidative capacity (T-AOC), indicating the mechanism of BBB protection is, in part, through antioxidant activity. Also, CAR 200 mg/kg treatment suppressed matrix metalloproteinase-9 (MMP-9) expression and increased ZO-1, occludin, and claudin-5 levels. These data indicate that CAR can promote antioxidant activity and decrease post-injury BBB permeability, further supporting CAR as a potential early therapeutic intervention that is inexpensive and more readily available worldwide. However, more experiments are required to determine CAR’s long-term impact on TBI pathophysiology.

Evaluating the neuroprotective effects of progesterone receptors on experimental traumatic brain injury: The PI3K/Akt pathway.

Studies have confirmed the salutary effects of progesterone (P4) on traumatic brain injury (TBI). This study investigated the beneficial effects of P4 via its receptors on TBI, and also whether progesterone receptors (PRs) can modulate TBI through PI3K/Akt pathway. Marmarou method was utilized to induce diffuse TBI in ovariectomized rats. P4 (1.7mg/kg) or the vehicle (oil) was administered 30min after TBI induction. Moreover, RU486 (PR antagonist) and its vehicle (DMSO) were injected before TBI induction and P4 injection. Brain Evans blue content, brain water content (WC), various oxidative stress parameters, IL-1β levels, tumor necrosis factor-α (TNF-α), histopathological alterations, and also phosphorylated Akt (p-Akt) and PI3K expressions in the brain were assessed 24h after TBI. The veterinary comma scale (VCS) was measured before and after TBI at different times. The findings revealed that P4 caused an increase in VCS and a decrease in brain WC, oxidative stress, TNF-α and IL-1β levels. RU486 inhibited the beneficial effects of P4 on these indices. Moreover, RU486 prevented the reduction of brain edema, inflammation, and apoptosis caused by P4. Moreover, P4 following TBI increased the expression of PI3K/p-Akt protein in the brain. RU486 eliminated the effects of P4 on PI3K/p-Akt expression. According to these findings, PRs are acting as critical mediators for the neuroprotective properties of P4 on oxidative stress, pro-inflammatory cytokine levels, and neurological outcomes. PRs also play an important role in regulating the PI3K/p-Akt expression and nongenomic function of P4.

The Effects of MK-801 on Apoptosis in a Traumatic Brain Injury Model in Rat Pups

Traumatic brain injury (TBI) is an essential cause of morbidity and mortality during childhood. Trauma causes some changes that result in delayed and elongated damage known as secondary injury, which is characterized by neuronal apoptosis. Based on this information, the aim of this study was to investigate the effect of MK-801, a competitive NMDA receptor antagonist, on apoptosis against hippocampal damage in rat pups after TBI. Forty-two, 10-day-old Wistar Albino rats were randomly divided into three groups: Control, a Trauma, and Treatment groups, each having fourteen rats. TBI was created by blunt trauma model. MK-801, was injected intraperitoneally at the doses of 1 mg/kg of body weight immediately after induction of TBI. The hippocampus tissues were harvested 4 days after TBI. Then CA1 and dentate gyrus (DG) regions were evaluated in terms of immunoreactivity with BAX, cytochrome C, and caspase 3. Based on this evaluation, the control group showed weakly BAX and Cytochrome C immunoreactivities in hippocampus, but elevated reactions were observed in TBI group. Especially, it was determined that the cytochrome c immunoreactivity was granular form in the neurons of hippocampus DG region. In the Treatment group decreased BAX and Cytochrome C immunoreactivities. While a weak caspase-3 immunoreactivity was observed in control group, stronger immunoreactivity was determined both DG and CA1 region of hippocampus in TBI group. In the Treatment group, caspase-3 immunoreactivity decreased in hippocampus region when compared to TBI group. Our results showed that treatment with MK-801 may significantly decreased apoptosis through BAX, Cytochrome C and caspase-3 pathway.

Role of Remifentanil on MAC, Bcl-2, and Bax Levels in Traumatic Brain Injury Rat Models

Abstract: Introduction: Traumatic Brain Injury (TBI) conditions require immediate treatment such as the administration of analgesics and sedation, including remifentanil. TBI will affect the levels of several inflammatory and apoptotic proteins such as MAC, Bax, and Bcl-2. Remifentanil with its high affinity to μ-receptors is thought to affect the levels of these proteins and has neuroprotective properties to prevent secondary brain injury. Objectives: This research aims to determine the effect of giving remifentanil on MAC, Bcl-2, and Bax levels in rats with traumatic brain injury. Materials and Methods: Experimental research was conducted on 24 male Wistar rats, which were randomly divided into four groups. The Group-1 (G1) received an intravenous injection of NaCl, the Group-2 (G2) was given normal saline after TBI induction using the modified Feeney method. Furthermore, the Group-3 and Group-4 (G3 and G4) received fentanyl or remifentanil after TBI induction. The rat brain tissue was analyzed for MAC, Bcl-2, and Bax levels using the ELISA method. The data were analyzed statistically by ANOVA test, followed by Post-Hoc Multiple Comparison Test (p<0.05). Results: The MAC and Bax levels were reduced by the administration of fentanyl and remifentanil to TBI subjects, but increased Bcl-2 levels. The Post Hoc Multiple comparisons showed a significant difference between all group pairs (p<0.05). Meanwhile, the group given remifentanil showed more optimal results than those with fentanyl. Conclusion: The administration of remifentanil injection can act as a neuroprotector in TBI model Wistar rats by decreasing MAC and Bax levels and increasing Bcl-2 levels. Keywords: Bax, Bcl-2, MAC, Remifentanil, Traumatic brain injury.

The Role of Inhaled Estradiol and Myrtenol, Alone and in Combination, in Modulating Behavioral and Functional Outcomes Following Traumatic Experimental Brain Injury: Hemodynamic, Molecular, Histological and Behavioral Study.

Traumatic brain injury (TBI) is an important and growing cause of disability worldwide, and its cognitive consequences may be particularly significant. This study assessed the neuroprotective impacts of estradiol (E2), myrtenol (Myr), and the combination of the two on the neurological outcome, hemodynamic parameters, learning and memory, brain-derived neurotrophic factor (BDNF) level, phosphoinositide 3-kinases (PI3K/AKT) signaling, and inflammatory and oxidative factors in the hippocampus after TBI. Eighty-four adult male Wistar rats were randomly divided into 12 groups with seven rats in each (six groups to measure intracranial pressure, cerebral perfusion pressure, brain water content, and veterinary coma scale, and six groups for behavioral and molecular studies): sham, TBI, TBI/vehicle, TBI/Myr, TBI/E2, and TBI/Myr + E2 (Myr 50mg/kg and E2 33.3μg/kg via inhalation for 30min after TBI induction). Brain injury was induced by using Marmarou's method. Briefly, a 300-g weight was dropped down from a 2-m height through a free-falling tube onto the head of the anesthetized animals. Veterinary coma scale, learning and memory, brain water content, intracranial pressure, and cerebral perfusion pressure were impaired following TBI, and inflammation and oxidative stress were raised in the hippocampus after TBI. The BDNF level and PI3K/AKT signaling were impaired due to TBI. Inhalation of Myr and E2 had protective effects against all negative consequences of TBI by decreasing brain edema and the hippocampal content of inflammatory and oxidant factors and also by improving BDNF and PI3K/AKT in the hippocampus. Based on these data, there were no differences between alone and combination administrations. Our results propose that Myr and E2 have neuroprotective effects on cognition impairments due to TBI.

Neuroinflammation aggravated by traumatic brain injury at high altitude is reversed by L-serine via NFAT1-mediated microglial polarization.

Traumatic brain injury (TBI) is one of the main causes of disability and death, especially in plateau areas, where the degree of injury is often more serious than in plain areas. It is likely that high altitude (HA) aggravates neuroinflammation; however, prior studies are limited. This study was designed to evaluate the effects of HA on the degree of TBI and the neuroprotective effects and underlying mechanisms of L-serine against TBI at HA (HA-TBI). In in vivo experiments, wild-type mice and mice with Nfat1 (Nfat1-/- ) deficiency in the C57BL/6 background were kept in a hypobaric chamber for 3 days under simulated conditions of 4,000 m, 6,000 m and 8,000 m above sea level. After leaving the chamber, the standardized TBI model was established immediately. Mice were then intraperitoneally injected with L-serine (342 mg.kg-1) 2 h after TBI and then daily for 5 days. Behavioral tests and histological analysis were assessed at different time points post TBI induction. In vitro, we applied primary cultured microglia for hypoxia treatment (1% O2 for 24 h). The major findings include the following: (1) with increasing altitude, the neurological function of TBI mice decreased, and the damage to cerebral gray matter and white matter became more significant, (2) L-serine significantly improved the sensorimotor function of mice, reversed the increase in brain lesion volume, and promoted the renovation of brain tissue after HA-TBI, (3) L-serine significantly decreased the activation of microglia and promoted microglia polarization toward the protective M2 phenotype both in vivo and in vitro, (4) L-serine significantly suppressed the expression of NFAT1 in mice after HA-TBI and inhibited NFAT1 expression in primary microglia after hypoxia, and (5) knockout of Nfat1 inhibited the inflammatory reaction caused by excessive activation of microglia, and L-serine lost its neuroprotective effect in Nfat1 knockout mice. The present study suggests that HA aggravates brain damage after TBI and that the damage also increases with increasing altitude. As an endogenous amino acid, L-serine may be a neuroprotective agent against HA-TBI, and suppression of NFAT1 in microglia is a potential therapy for neuroinflammation in the future.

Traumatic Brain Injury in a Well: A Modular Three-Dimensional Printed Tool for Inducing Traumatic Brain Injury In vitro.

Traumatic brain injury (TBI) is a major health problem that affects millions of persons worldwide every year among all age groups, mainly young children, and elderly persons. It is the leading cause of death for children under the age of 16 and is highly correlated with a variety of neuronal disorders, such as epilepsy, and neurodegenerative disease, such as Alzheimer's disease or amyotrophic lateral sclerosis. Over the past few decades, our comprehension of the molecular pathway of TBI has improved, yet despite being a major public health issue, there is currently no U.S. Food and Drug Administration-approved treatment for TBI, and a gap remains between these advances and their application to the clinical treatment of TBI. One of the major hurdles for pushing TBI research forward is the accessibility of TBI models and tools. Most of the TBI models require costume-made, complex, and expensive equipment, which often requires special knowledge to operate. In this study, we present a modular, three-dimensional printed TBI induction device, which induces, by the pulse of a pressure shock, a TBI-like injury on any standard cell-culture tool. Moreover, we demonstrate that our device can be used on multiple systems and cell types and can induce repetitive TBIs, which is very common in clinical TBI. Further, we demonstrate that our platform can recapitulate the hallmarks of TBI, which include cell death, decrease in neuronal functionality, axonal swelling (for neurons), and increase permeability (for endothelium). In addition, in view of the continued discussion on the need, benefits, and ethics of the use of animals in scientific research, this in vitro, high-throughput platform will make TBI research more accessible to other labs that prefer to avoid the use of animals yet are interested in this field. We believe that this will enable us to push the field forward and facilitate/accelerate the availability of novel treatments.

Satureja khuzistanica Jamzad essential oil and pure carvacrol attenuate TBI-induced inflammation and apoptosis via NF-κB and caspase-3 regulation in the male rat brain

Traumatic brain injury (TBI) causes progressive dysfunction that induces biochemical and metabolic changes that lead to cell death. Nevertheless, there is no definitive FDA-approved therapy for TBI treatment. Our previous immunohistochemical results indicated that the cost-effective natural Iranian medicine, Satureja khuzistanica Jamzad essential oil (SKEO), which consists of 94.16% carvacrol (CAR), has beneficial effects such as reducing neuronal death and inflammatory markers, as well as activating astrocytes and improving neurological outcomes. However, the molecular mechanisms of these neuroprotective effects have not yet been elucidated. This study investigated the possible mechanisms involved in the anti-inflammatory and anti-apoptotic properties of SKEO and CAR after TBI induction. Eighty-four male Wistar rats were randomly divided into six groups: Sham, TBI, TBI + Vehicle, TBI + CAR (100 and 200 mg/kg), and TBI + SKEO (200 mg/kg) groups. After establishing the “Marmarou” weight drop model, diffuse TBI was induced in the rat brain. Thirty minutes after TBI induction, SKEO & CAR were intraperitoneally injected. One day after TBI, injured rats exhibited significant brain edema, neurobehavioral dysfunctions, and neuronal apoptosis. Western blot results revealed upregulation of the levels of cleaved caspase-3, NFκB p65, and Bax/Bcl-2 ratio, which was attenuated by CAR and SKEO (200 mg/kg). Furthermore, the ELISA results showed that CAR treatment markedly prevents the overproduction of the brain pro-inflammatory cytokines, including IL-1β, TNF-α, and IL-6. Moreover, the neuron-specific enolase (NSE) immunohistochemistry results revealed the protective effect of CAR and SKEO on post-TBI neuronal death. The current study revealed that the possible neuroprotective mechanisms of SKEO and CAR might be related to (at least in part) modulating NF-κB regulated inflammation and caspase-3 protein expression. It also suggested that CAR exerts more potent protective effects than SKEO against TBI. Nevertheless, the administration of SKEO and CAR may express a novel therapeutic approach to ameliorate TBI-related secondary phase neuropathological outcomes.

Neuroprotective effects of chloroquine on neurological scores, blood-brain barrier permeability, and brain edema after traumatic brain injury in male rats

Background: Traumatic brain injury (TBI) is one of leading causes of death among young people worldwide. Chloroquine, an antimalarial drug, has been shown to easily cross the blood-brain barrier (BBB) and inhibit autophagy in a variety of disorders, including Alzheimer disease and brain ischemia. We investigated the effects of chloroquine on neuronal protection after induction of brain trauma in male rats.Methods: A total of 120 male Wistar rats were treated with chloroquine at doses of 1.5, 3, and 6 mg/kg intraperitoneally after induction of diffuse TBIs. The veterinary coma scale was used to assess short-term neurological deficits. BBB disruption was evaluated using the Evans Blue dye method 6-hour post-injury. Vestibulomotor function was evaluated using the beam walk and beam balance methods. Histopathological changes in the brain tissue in different groups were evaluated using light microscopy and hematoxylin-eosin staining. Brain water and cerebrospinal fluid (CSF) contents of matrix metalloproteinase 9 (MMP-9) were assessed using the wet/dry method and enzyme-linked immunosorbent assay, respectively.Results: The results showed that injecting chloroquine (3 and 6 mg/kg) 30 minutes after TBI significantly reduced brain edema and BBB disruption, and recovered neurological deficits post-TBI (P&lt;0.01). Furthermore, CSF MMP-9 was significantly reduced after administration of 1.5 mg/kg chloroquine (P&lt;0.01).Conclusion: Chloroquine has neuroprotective effects in the brain, and thus, has the potential to mitigate the effects of brain trauma. It is possible that the anti-inflammatory and neurogenic effects of chloroquine are due to a decrease in MMP secretion in the CSF.

Assessing Dominant-Submissive Behavior in Adult Rats Following Traumatic Brain Injury

Competition over resources such as food, territory, and mates significantly influences relationships within animal species and is mediated through social hierarchies that are often based on dominant-submissive relationships. The dominant-submissive relationship is a normal behavioral pattern among the individuals of a species. Traumatic brain injury is a frequent cause of social interaction impairment and the reorganization of dominant-submissive relationships in animal pairs. This protocol describes submissive behavior in adult male Sprague-Dawley rats after the induction of traumatic brain injury using a fluid-percussion model compared to naive rats through a series of dominant-submissive tests performed between 29 days and 33 days after induction. The dominant-submissive behavior test shows how brain injury can induce submissive behavior in animals competing for food. After traumatic brain injury, the rodents were more submissive, as indicated by them spending less time at the feeder and being less likely to arrive first at the trough compared to the control animals. According to this protocol, submissive behavior develops after traumatic brain injury in adult male rats.

The Effect of Remifentanil, MgSO4, or Remifentanil-MgSO4 as Neuroprotectors on BDNF, MAC, and Caspase-3 Levels in Wistar Rats with Traumatic Brain Injury

BACKGROUND: Traumatic brain injury (TBI) can lead to cell death and neurologic dysfunction. Meanwhile, Remifentanyl is an opioid with potent analgesia, while magnesium sulfate (MgSO4) has antinociceptive properties that can prevent hemodynamic instability during laryngoscopy. AIM: This study aims to examine the effect of remifentanil, MgSO4 and their combination on BDNF, MAC, and Caspase-3 levels in Wistar rat models with TBI. METHODOLOGY: An experimental study was conducted on 30 male Wistar rats which were randomly divided into five groups. The control group (G1) received normal saline, the induced group (G2) received normal saline after TBI induction using the modified Feeney method, and the treated group (G3, G4, and G5) received remifentanil, MgSO4, and their combination after TBI induction. The rats’ brain tissues were analyzed for BDNF, MAC, and Caspase-3 levels using ELISA. The data were analyzed statistically with ANOVA followed by post hoc Multiple Comparison Test (p &lt; 0.05). RESULTS: Treatment with remifentanil, MgSO4 or the combination of both in TBI subjects reduced MAC and Caspase-3 but increased the BDNF level. The post hoc multiple comparisons showed significant differences in all groups except groups 3 and 5 in terms of MAC (p = 0.190) and Caspase-3 (p = 0.999). The combination of remifentanil-MgSO4 increased BDNF levels significantly. CONCLUSION: The administration of remifentanil, MgSO4 , or their combination can serve as a neuroprotector in Wistar rat models with TBI by lowering MAC and Caspase-3 as well as increasing BDNF levels.

Antioxidant-based neuroprotective effect of dimethylsulfoxide against induced traumatic brain injury in a rats model

Traumatic brain injury (TBI) has been the result of neurological deficit and oxidative stress. This study evaluated the antioxidative neuroprotective property and learning and memory-enhancing effects of dimethyl sulfoxide (DMSO) in a rat model after the induction of TBI. 21 albino rats with 7 rats per group were used in this study. Group I was induced with TBI and treated with DMSO at 67.5mg/kg orally once daily which started 30min after the induction of TBI and lasted 21days. Group II was induced with TBI but not treated while Group III was neither induced with TBI nor treated. Assessment of behavioral function (Learning and memory, anxiety and motor function), the level of an antioxidant enzymes and their gene expression (superoxide dismutase, catalase, glutathione peroxidase), the biomarkers of oxidative stress (malondialdehyde) and S100B levels as well as brain tissues histological studies were conducted. Administration of DMSO to rats with induced TBI has improved learning and memory, locomotor function and decreased anxiety in Group I compared to Group II. Moreover, the level of S100B was significantly (p < 0.05) lower in Group I compared to Group II. Treatment with DMSO also decreased lipid peroxidation significantly (p < 0.05) compared to Group II. There exists a significant (p < 0.05) increase in CAT, SOD, and GPX activities in Group I compared to Group II. Therefore, DMSO has demonstrated a potential antioxidative neuroprotective effect through its ability to increase the level of antioxidant enzymes which they quench and inhibit the formation of ROS, thereby improving cognitive functions.

The effect of Riluzole on neurological outcomes, blood-brain barrier, brain water and neuroinflammation in traumatic brain injury

BackgroundRiluzole (RLZ) is a potent anticonvulsant drug that reveals neuroprotective effects on neurological disease by inhibiting the release of glutamate and increasing its uptake. This study aims to investigate the potential neuroprotective effects of Riluzole in a rat model with acute severe traumatic brain injury (TBI). Materials and MethodsIn this study, seven groups of male Wistar rats were investigated including Sham, Intact, TBI, Saline (TBI + intraperitoneal (i.p) injection of normal saline), TBI + i.p injection of Riluzole in 2,4 and 8 mg/kg doses (RLZ 2, RLZ 4 and RLZ 8 groups), induction of severe diffuse TBI performed by weight dropping Marmarou model, and evaluation of short-term neurological deficits by using veterinary coma scale (VCS), beam-balance and beam-walk tasks. Histopathological changes in neural tissue were evaluated by using hematoxylin and eosin staining and light microscopy. Evaluation of blood-brain barrier (BBB) permeability was performed by using the Evans Blue method 6 h after traumatization. Brain water content assessment was performed by using the wet-dry method and the level of IL-1β and IL-10 was determined by using an enzyme-linked immunosorbent assay (ELISA). ResultsTreatment with Riluzole improves neurological function, VCS score, and vestibulomotor function, reduces pathological changes of neural tissue, brain edema, and level of IL-1β, and increases IL-10 concentration in CSF compared to the saline group (p < 0.0001). Treatment with 4 and 8 mg/kg of Riluzole reveals a significant therapeutic effect on consequences of TBI. This effect was enhanced by an increase in the dose of Riluzole from 4 to 8 mg/kg, but no significant changes were seen after administration of 2 mg/kg of Riluzole. ConclusionRiluzole can reduce the first and second phase of TBI damage by lowering inflammation, brain edema, histopathological destruction, BBB permeability, level of IL- 1β, and increasing IL-10 in CSF; it is highly suggested to use Riluzole in further studies and human trials, and also to consider it as a therapeutic compound in the treatment of traumatic brain injury.

Branched-Chain Amino Acids Are Neuroprotective Against Traumatic Brain Injury and Enhance Rate of Recovery: Prophylactic Role for Contact Sports and Emergent Use

Branched-chain amino acids (BCAAs) are known to be neurorestorative after traumatic brain injury (TBI). Despite clinically significant improvements in severe TBI patients given BCAAs after TBI, the approach is largely an unrecognized option. Further, TBI continues to be the most common cause of morbidity and mortality in adolescents and adults. To date, no study has evaluated whether BCAAs can be preventive or neuroprotective if taken before a TBI. We hypothesized that if BCAAs were elevated in the circulation before TBI, the brain would readily access the BCAAs and the severity of injury would be reduced. Before TBI induction with a standard weight-drop method, 50 adult mice were randomized into groups that were shams, untreated, and pre-treated, post-treated, or pre- + post-treated with BCAAs. Pre-treated mice received BCAAs through supplemented water and were dosed by oral gavage 45 min before TBI induction. All mice underwent beam walking to assess motor recovery, and the Morris water maze assessed cognitive function post-injury. On post-injury day 14, brains were harvested to assess levels of astrocytes and microglia with glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (IBA-1) immunohistochemistry, respectively. Pre-treated and pre- +post-treated mice exhibited significantly better motor recovery and cognitive function than the other groups. The pre- + post-treated group had the best overall memory performance, whereas the pre-treated and post-treated groups only had limited improvements in memory compared to untreated animals. Pre- + post-treated brains had levels of GFAP that were similar to the sham group, whereas the pre-only and post-only groups showed increases. Although trends existed, no meaningful changes in IBA-1 were detected. This is the first study, animal or human, to demonstrate that BCAA are neuroprotective and substantiates their neurorestorative benefits after TBI, most likely through the important roles of BCAAs to glutamate homeostasis.

Exogenous hydrogen sulfide restores CSE and CBS but no 3-MST protein expression in the hypothalamus and brainstem after severe traumatic brain injury.

Hydrogen sulfide (H2S) is a gasotransmitter endogenously synthesized by cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS), and 3-mercaptopiruvate sulfurtransferase (3-MST) enzymes. H2S exogenous administration prevents the development of hemodynamic impairments after traumatic brain injury (TBI). Since the hypothalamus and the brainstem highly regulate the cardiovascular system, this study aimed to evaluate the effect of NaHS subchronic treatment on the changes of H2S-sythesizing enzymes in those brain areas after TBI and in physiological conditions. For that purpose, animals were submitted to a lateral fluid percussion injury, and the changes in CBS, CSE, and 3-MST protein expression were measured by western blot at days 1, 2, 3, 7, and 28 in the vehicle group, and 7 and 28days after NaHS treatment. After severe TBI induction, we found a decrease in CBS and CSE protein expression in the hypothalamus and brainstem; meanwhile, 3-MST protein expression diminished only in the hypothalamus compared to the Sham group. Remarkably, i.p. daily injections of NaHS, an H2S donor, (3.1mg/kg) during seven days: (1) restored CBS and CSE but no 3-MST protein expression in the hypothalamus at day 28 post-TBI; (2) reestablished only CSE in brainstem 7 and 28days after TBI; and (3) did not modify H2S-sythesizing enzymes protein expression in uninjured animals. Mainly, our results show that the NaHS effect on CBS and CSE protein expression is observed in a time- and tissue-dependent manner with no effect on 3-MST expression, which may suggest a potential role of H2S synthesis in hypothalamus and brainstem impairments observed after TBI.

BAY61‑3606 attenuates neuroinflammation and neurofunctional damage by inhibiting microglial Mincle/Syk signaling response after traumatic brain injury.

Neuroinflammatory processes mediated by microglial activation and subsequent neuronal damage are the hallmarks of traumatic brain injury (TBI). As an inhibitor of the macrophage-inducible C-type lectin (Mincle)/spleen tyrosine kinase (Syk) signaling pathway, BAY61-3606 (BAY) has previously demonstrated anti-inflammatory effects on some pathological processes, such as acute kidney injury, by suppressing the inflammatory macrophage response. In the present study, the potential effects of BAY on microglial phenotype and neuroinflammation after TBI were investigated. BAY (3 mg/kg) was first administered into mice by intraperitoneal injection after TBI induction in vivo and microglia were also treated with BAY (2 µM) in vitro. The levels of inflammatory factors in microglia were assessed using reverse transcription-quantitative PCR and ELISA. Cortical neuron, myelin sheath, astrocyte and cerebrovascular endothelial cell markers were detected using immunofluorescence. The levels of components of the Mincle/Syk/NF-κB signaling pathway [Mincle, phosphorylated (p)-Syk and NF-κB], in addition to proteins associated with inflammation (ASC, caspase-1, TNF-α, IL-1β and IL-6), apoptosis (Bax and Bim) and tight junctions (Claudin-5), were measured via western blotting and ELISA. Migration and chemotaxis of microglial cells were evaluated using Transwell and agarose spot assays. Neurological functions of the mice were determined in vivo using the modified neurological severity scoring system and a Morris water maze. The results of the present study revealed that the expression levels of proteins in the Mincle/Syk/NF-κB signaling pathway (including Mincle, p-Syk and p-NF-κB), inflammatory cytokines (TNF-α, IL-1β and IL-6), proteins involved in inflammation (ASC and caspase-1), apoptotic markers (Bax and Bim) and the tight junction protein Claudin-5 were significantly altered post-TBI. BAY treatment reversed these effects in both the cerebral cortex extract-induced cell model and the controlled cortical impact mouse model. BAY was also revealed to suppress activation of the microglial proinflammatory phenotype and microglial migration. In addition, BAY effectively attenuated TBI-induced neurovascular unit damage and neurological function deficits. Taken together, these findings provided evidence that BAY may inhibit the Mincle/Syk/NF-κB signaling pathway in microglia; this in turn could attenuate microglia-mediated neuroinflammation and improve neurological deficits following TBI.

Effects of Alpha-2 Adrenergic Agonist Mafedine on Brain Electrical Activity in Rats after Traumatic Brain Injury.

The search for and development of new neuroprotective (or cerebroprotective) drugs, as well as suitable methods for their preclinical efficacy evaluation, are priorities for current biomedical research. Alpha-2 adrenergic agonists, such as mafedine and dexmedetomidine, are a highly appealing group of drugs capable of reducing neurological deficits which result from brain trauma and vascular events in both experimental animals and human patients. Thus, our aim was to assess the effects of mafedine and dexmedetomidine on the brain’s electrical activity in a controlled cortical-impact model of traumatic brain injury (TBI) in rats. The functional status of the animals was assessed by electrocorticography (ECoG), using ECoG electrodes which were chronically implanted in different cortical regions. The administration of intraperitoneal mafedine sodium at 2.5 mg∙kg−1 at 1 h after TBI induction, and daily for the following 6 days, restored interhemispheric connectivity in remote brain regions and intrahemispheric connections within the unaffected hemisphere at post-TBI day 7. Animals that had received mafedine sodium also demonstrated an improvement in cortical responses to photic and somatosensory stimulation. Dexmedetomidine at 25 μg∙kg−1 did not affect the brain’s electrical activity in brain-injured rats. Our results confirm the previously described neuroprotective effects of mafedine sodium and suggest that ECoG registration and analysis are a viable method evaluating drug efficacy in experimental animal models of TBI.

Deferoxamine reduces amyloid-beta peptides genesis and alleviates neural apoptosis after traumatic brain injury.

Traumatic brain injury (TBI) is recognized as the most influential risk factor for neurodegenerative diseases later in life, including Alzheimer's disease. The aberrant genesis of amyloid-β peptides, which is triggered by TBI, is associated with the development of Alzheimer's disease. Evidence suggests that iron plays a role in both the production of amyloid-β and its neurotoxicity, and iron overload has been noted in the brain after TBI. We therefore investigated the effects of an iron-chelating treatment on amyloid-β genesis in a weight-drop model of TBI in mice. Human brain samples were obtained from patients undergoing surgery for severe brain trauma. The Institute of Cancer Research mice were treated with deferoxamine by intraperitoneal injection after TBI induction. Changes in amyloid-β(1-42) were assessed using western blot and immunohistochemical staining. Ferritin was also detected using western blot to investigate iron deposition in the mice brain. Immunofluorescent terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was also performed to evaluate neural apoptosis. The amyloid-β(1-42) was markedly elevated after TBI in both humans and mice. Deferoxamine treatment in mice significantly decreased the levels of both amyloid-β(1-42) and ferritin in the brain, and reduced TBI-induced neural cell apoptosis. The iron chelator deferoxamine can alleviate the increase of amyloid-β(1-42) in the brain after TBI, and may therefore be a potential therapeutic strategy to prevent TBI patients from undergoing neurodegenerative processes.