A role of Na+, K+ -ATPase in spatial memory deficits and inflammatory/oxidative stress after recurrent concussion in adolescent rats.

Sports-related concussions are particularly common during adolescence, and there is insufficient knowledge about how recurrent concussions in this phase of life alter the metabolism of essential structures for memory in adulthood. In this sense, our experimental data revealed that seven recurrent concussions (RC) in 35-day-old rats decreased short-term and long-term memory in the object recognition test (ORT) 30 days after injury. The RC protocol did not alter motor and anxious behavior and the immunoreactivity of brain-derived neurotrophic factor (BDNF) in the cerebral cortex. Recurrent concussions induced the inflammatory/oxidative stress characterized here by increased glial fibrillary acidic protein (GFAP), interleukin 1ß (IL 1ß), 4-hydroxynonenal (4 HNE), protein carbonyl immunoreactivity, and 2',7'-dichlorofluorescein diacetate oxidation (DCFH) levels and lower total antioxidant capacity (TAC). Inhibited Na+,K+-ATPase activity (specifically isoform α2/3) followed by Km (Michaelis-Menten constant) for increased ATP levels and decreased immunodetection of alpha subunit of this enzyme, suggesting that cognitive impairment after RC is caused by the inability of surviving neurons to maintain ionic gradients in selected targets to inflammatory/oxidative damage, such as Na,K-ATPase activity.

Temporal patterns of microglial activation in white matter following experimental mild traumatic brain injury: a systematic literature review.

Mild traumatic brain injuries (mTBIs) are a prevalent form of injury that can result in persistent neurological impairments. Microglial activation has become increasingly recognized as a key process regulating the pathology of white matter in a wide range of brain injury and disease contexts. As white matter damage is known to be a major contributor to the impairments that follow mTBI, microglia have rightfully become a common target of investigation for the development of mTBI therapies and biomarkers. Recent work has demonstrated that the efficacy of microglial manipulation as a therapeutic intervention following injury or disease is highly time-sensitive, emphasizing the importance of advancing our understanding of the dynamics of post-mTBI microglial activation from onset to resolution. Current reporting of microglial activation in experimental studies of mTBI is non-standardized, which has limited our ability to identify concrete patterns of post-mTBI microglial activation over time. In this review, we examine preclinical studies of mTBI that report on microglial activation in white matter regions to summarize our current understanding of these patterns. Specifically, we summarize timecourses of post-mTBI microglial activation in white matter regions of the brain, identify factors that influence this activation, examine the temporal relationship between microglial activation and other post-mTBI assessments, and compare the relative sensitivities of various methods for detecting microglial activation. While the lack of replicated experimental conditions has limited the extent of conclusions that can confidently be drawn, we find that microglia are activated over a wide range of timecourses following mTBI and that microglial activation is a long-lasting outcome of mTBI that may resolve after most typical post-mTBI assessments, with the exception of those measuring oligodendrocyte lineage cell integrity. We identify several understudied parameters of post-mTBI microglial activation in white matter, such as the inclusion of female subjects. This review summarizes our current understanding of the progression of microglial activation in white matter structures following experimental mTBI and offers suggestions for important future research directions.

Microglia dynamics in adolescent traumatic brain injury.

Repetitive, mild traumatic brain injuries (RmTBIs) are increasingly common in adolescents and encompass one of the largest neurological health concerns in the world. Adolescence is a critical period for brain development where RmTBIs can substantially impact neurodevelopmental trajectories and life-long neurological health. Our current understanding of RmTBI pathophysiology suggests key roles for neuroinflammation in negatively regulating neural health and function. Microglia, the brain's resident immune population, play important roles in brain development by regulating neuronal number, and synapse formation and elimination. In response to injury, microglia activate to inflammatory phenotypes that may detract from these normal homeostatic, physiological, and developmental roles. To date, however, little is known regarding the impact of RmTBIs on microglia function during adolescent brain development. This review details key concepts surrounding RmTBI pathophysiology, adolescent brain development, and microglia dynamics in the developing brain and in response to injury, in an effort to formulate a hypothesis on how the intersection of these processes may modify long-term trajectories.

An investigation of plasma interleukin-6 in sport-related concussion.

BACKGROUND: Increasing evidence suggests inflammation is an important component of concussion pathophysiology. However, its etiology, restitution, and potential clinical repercussions remain unknown. The purpose of the current study was to compare the blood concentrations of interleukin (IL) -6, a prominent inflammatory cytokine, between healthy athletes and athletes with a sport-related concussion (SRC), while addressing the potential confounds of sex, recent physical activity, and the interacting effect of concussion history. METHOD: A prospective, observational cohort study was conducted on athletes at a single academic institute participating across 13 interuniversity sports. Follow-up of 96 athletes who agreed to provide a blood sample was completed: 41 athletes with a physician diagnosed SRC, and 55 healthy athletes. Ella™, the high sensitivity immunoassay system by ProteinSimple was used to measure peripheral plasma concentrations of IL-6 within the first week (median = 4 days, range = 2-7) following injury. A resampled ordinary least squares regression was used to evaluate the relationship between IL-6 concentrations and concussion status, while partial least squares regression was used to evaluate the relationship between IL-6 and both symptom burden and time to clinical recovery. RESULTS: Regression analysis identified a negative relationship between plasma IL-6 concentrations and the interaction between an acute SRC and a history of concussion (ß = -0.29, p = 0.029). IL-6 did not differ between healthy athletes and those with an acute SRC independent of concussion history, and was not correlated with either recovery time or symptom burden in athletes with SRC. CONCLUSION: Perturbations to circulating IL-6 concentrations, a key inflammatory cytokine, may be more pronounced following SRC in athletes who have a history of concussion. These results add to a growing body of evidence supporting the involvement of inflammation at all phases of recovery following SRC, and potentially support a concomitant effect of prior concussion on acute SRC pathophysiology.

The relationship between symptom burden and systemic inflammation differs between male and female athletes following concussion.

BACKGROUND: Inflammation appears to be an important component of concussion pathophysiology. However, its relationship to symptom burden is unclear. Therefore, the purpose of this study was to evaluate the relationship between symptoms and inflammatory biomarkers measured in the blood of male and female athletes following a sport-related concussion (SRC). RESULTS: Forty athletes (n = 20 male, n = 20 female) from nine interuniversity sport teams at a single institution provided blood samples within one week of an SRC. Twenty inflammatory biomarkers were quantitated by immunoassay. The Sport Concussion Assessment Tool version 5 (SCAT-5) was used to evaluate symptoms. Partial least squares (PLS) analyses were used to evaluate the relationship(s) between biomarkers and symptoms. In males, a positive correlation between interferon (IFN)-γ and symptom severity was observed following SRC. The relationship between IFN-γ and symptoms was significant among all symptom clusters, with cognitive symptoms displaying the largest effect. In females, a significant negative relationship was observed between symptom severity and cytokines IFN-γ, tumor necrosis factor (TNF)-α, and myeloperoxidase (MPO); a positive relationship was observed between symptom severity and MCP-4. Inflammatory mediators were significantly associated with all symptom clusters in females; the somatic symptom cluster displayed the largest effect. CONCLUSION: These results provide supportive evidence of a divergent relationship between inflammation and symptom burden in male and female athletes following SRC. Future investigations should be cognizant of the potentially sex-specific pathophysiology underlying symptom presentation.

Neuroprotection Following Concussion: The Potential Role for Cannabidiol.

Cannabidiol (CBD) has been generating increasing interest in medicine due to its therapeutic properties and an apparent lack of negative side effects. Research has suggested that high dosages of CBD can be taken acutely and chronically with little to no risk. This review focuses on the neuroprotective effects of a CBD, with an emphasis on its implications for recovering from a mild traumatic brain injury (TBI) or concussion. CBD has been shown to influence the endocannabinoid system, both by affecting cannabinoid receptors and other receptors involved in the endocannabinoid system such as vanilloid receptor 1, adenosine receptors, and 5-hydroxytryptamine via cannabinoid receptor-independent mechanisms. Concussions can result in many physiological consequences, potentially resulting in post-concussion syndrome. While impairments in cerebrovascular and cardiovascular physiology following concussion have been shown, there is unfortunately still no single treatment available to enhance recovery. CBD has been shown to influence the blood brain barrier, brain-derived neurotrophic factors, cognitive capacity, the cerebrovasculature, cardiovascular physiology, and neurogenesis, all of which have been shown to be altered by concussion. CBD can therefore potentially provide treatment to enhance neuroprotection by reducing inflammation, regulating cerebral blood flow, enhancing neurogenesis, and protecting the brain against reactive oxygen species. Double-blind randomized controlled trials are still required to validate the use of CBD as medication following mild TBIs, such as concussion.

Acute elevation of serum inflammatory markers predicts symptom recovery after concussion.

OBJECTIVE: To test the hypothesis that acute elevations in serum inflammatory markers predict symptom recovery after sport-related concussion (SRC). METHODS: High school and collegiate football players (n = 857) were prospectively enrolled. Forty-one athletes with concussion and 43 matched control athletes met inclusion criteria. Serum levels of interleukin (IL)-6, IL-1ß, IL-10, tumor necrosis factor, C-reactive protein, interferon-γ, and IL-1 receptor antagonist and Sport Concussion Assessment Tool, 3rd edition (SCAT3) symptom severity scores were collected at a preinjury baseline, 6 and 24-48 hours postinjury, and approximately 8, 15, and 45 days following concussion. The number of days that athletes were symptomatic following SRC (i.e., duration of symptoms) was the primary outcome variable. RESULTS: IL-6 and IL-1RA were significantly elevated in athletes with concussion at 6 hours relative to preinjury and other postinjury visits, as well as compared to controls (ps ≤ 0.001). IL-6 and IL-1RA significantly discriminated concussed from control athletes at 6 hours postconcussion (IL-6 area under receiver operating characteristic curve 0.79 [95% confidence interval (CI) 0.65-0.92], IL-1RA AUC 0.79 [95% CI 0.67-0.90]). Further, IL-6 levels at 6 hours postconcussion were significantly associated with the duration of symptoms (hazard ratio for symptom recovery = 0.61 [95% CI 0.38-0.96], p = 0.031). CONCLUSIONS: Results support the potential utility of IL-6 and IL-1RA as serum biomarkers of SRC and demonstrate the potential of these markers in identifying athletes at risk for prolonged recovery after SRC. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that serum levels of IL-6 and IL-1RA 6 hours postconcussion significantly discriminated concussed from control athletes.

The effect of an acute systemic inflammatory insult on the chronic effects of a single mild traumatic brain injury.

A small but significant proportion of mild traumatic brain injury (mTBI) sufferers will report persistent symptoms, including depression, anxiety and cognitive deficits, in the months, or even years, following the initial event. This is known as post-concussion syndrome and its pathogenesis is not yet known. This study sought to investigate the role of a peripheral inflammatory insult in the development of ongoing behavioral symptoms following a mTBI. To investigate, male Sprague-Dawley rats were administered a single mTBI using the diffuse impact-acceleration model to generate ∼100G of force. Sham animals underwent surgery only. At 5days following surgery, rats were given either the TLR4 agonist, lipopolysaccharide (LPS, 0.1mg/kg), or saline via an intraperitoneal injection. mTBI animals showed an exaggerated response to LPS, with an increase in the expression of pro-inflammatory cytokines within the hippocampus at 24h post-dose, an effect not seen in sham animals. This was associated with the development of persistent behavioral deficits in the mTBI:LPS animals at 3 months post-injury. These behavioral deficits consisted of increased time spent immobile on the forced swim-test, indicative of depressive like behavior, impaired cognitive performance on the Barnes Maze and decreased anxiety on the Elevated Plus Maze. In contrast, animals administered mTBI alone had no deficits. This study provides evidence that a peripheral inflammatory stimulus can facilitate ongoing symptoms following a mTBI. As such this provides a basis for further exploration of exogenous factors which promote immune system activation as potential targets for intervention to allow the resolution of symptoms following a mTBI.

Neuroinflammation, myelin and behavior: Temporal patterns following mild traumatic brain injury in mice.

Traumatic brain injury (TBI) results in white matter injury (WMI) that is associated with neurological deficits. Neuroinflammation originating from microglial activation may participate in WMI and associated disorders. To date, there is little information on the time courses of these events after mild TBI. Therefore we investigated (i) neuroinflammation, (ii) WMI and (iii) behavioral disorders between 6 hours and 3 months after mild TBI. For that purpose, we used experimental mild TBI in mice induced by a controlled cortical impact. (i) For neuroinflammation, IL-1b protein as well as microglial phenotypes, by gene expression for 12 microglial activation markers on isolated CD11b+ cells from brains, were studied after TBI. IL-1b protein was increased at 6 hours and 1 day. TBI induced a mixed population of microglial phenotypes with both pro-inflammatory, anti-inflammatory and immunomodulatory markers from 6 hours to 3 days post-injury. At 7 days, microglial activation was completely resolved. (ii) Three myelin proteins were assessed after TBI on ipsi- and contralateral corpus callosum, as this structure is enriched in white matter. TBI led to an increase in 2',3'-cyclic-nucleotide 3'-phosphodiesterase, a marker of immature and mature oligodendrocyte, at 2 days post-injury; a bilateral demyelination, evaluated by myelin basic protein, from 7 days to 3 months post-injury; and an increase in myelin oligodendrocyte glycoprotein at 6 hours and 3 days post-injury. Transmission electron microscopy study revealed various myelin sheath abnormalities within the corpus callosum at 3 months post-TBI. (iii) TBI led to sensorimotor deficits at 3 days post-TBI, and late cognitive flexibility disorder evidenced by the reversal learning task of the Barnes maze 3 months after injury. These data give an overall invaluable overview of time course of neuroinflammation that could be involved in demyelination and late cognitive disorder over a time-scale of 3 months in a model of mild TBI. This model could help to validate a pharmacological strategy to prevent post-traumatic WMI and behavioral disorders following mild TBI.

Long-Term Kinetics of Immunologic Components and Neurological Deficits in Rats Following Repetitive Mild Traumatic Brain Injury.

BACKGROUND Despite growing awareness of repetitive mild traumatic brain injury (rmTBI), understanding of the involvement of long-term kinetics of immunologic components in the central and peripheral immune system took part remains incomplete. The present study aimed to provide a quantitative assay for certain immune system parameters in rmTBI rats. MATERIAL AND METHODS Neurological functions were assessed by modified Neurological Severity Score (mNSS) and Morris Water Maze (MWM), immunologic components from brain and peripheral blood were analyzed by flow cytometry (FCM), and concentrations of inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 were measure by enzyme-linked immunosorbent assay (ELISA). RESULTS Neurological functions of rmTBI rats were seriously impaired. In the brain, T cells were up-regulated and peaked at week 1. The percentage of CD4+ T cells decreased from week 1 to week 4, while CD8+ T cells notably decreased at week 1, then increased until week 4. The infiltration proportion of Treg cells was reduced at week 1 and peaked at week 2. CD86+/CD11b+ M1 peaked at week 4 and CD206+/CD11b+ M2 rose at week 1. IL-6/IL-10 showed a similar pattern, whose rise corresponded to the decrease in TNF-α at week 2 after rmTBI. FCM demonstrated peripheral immune dysfunction after rmTBI. CONCLUSIONS mNSS and MWM demonstrated neuronal deficits in rmTBI rats, and central and peripheral immune systems were implicated in the pathophysiological processes of rmTBI. Long-term immune response may play dual roles in injury and repair of rmTBI.

Toll like receptor 4 activation can be either detrimental or beneficial following mild repetitive traumatic brain injury depending on timing of activation.

A history of repeated concussion has been linked to the later development of neurodegeneration, which is associated with the accumulation of hyperphosphorylated tau and the development of behavioral deficits. However, the role that exogenous factors, such as immune activation, may play in the development of neurodegeneration following repeated mild traumatic brain injury (rmTBI) has not yet been explored. To investigate, male Sprague-Dawley rats were administered three mTBIs 5days apart using the diffuse impact-acceleration model to generate ∼100G. Sham animals underwent surgery only. At 1 or 5days following the last injury rats were given the TLR4 agonist, lipopolysaccharide (LPS, 0.1mg/kg), or saline. TLR4 activation had differential effects following rmTBI depending on the timing of activation. When given at 1day post-injury, LPS acutely activated microglia, but decreased production of pro-inflammatory cytokines like IL-6. This was associated with a reduction in neuronal injury, both acutely, with a restoration of levels of myelin basic protein (MBP), and chronically, preventing a loss of both MBP and PSD-95. Furthermore, these animals did not develop behavioral deficits with no changes in locomotion, anxiety, depressive-like behavior or cognition at 3months post-injury. Conversely, when LPS was given at 5days post-injury, it was associated acutely with an increase in pro-inflammatory cytokine production, with an exacerbation of neuronal damage and increased levels of aggregated and phosphorylated tau. At 3months post-injury, there was a slight exacerbation of functional deficits, particularly in cognition and depressive-like behavior. This highlights the complexity of the immune response following rmTBI and the need to understand how a history of rmTBI interacts with environmental factors to influence the potential to develop later neurodegeneration.

Repetitive Closed-Head Impact Model of Engineered Rotational Acceleration Induces Long-Term Cognitive Impairments with Persistent Astrogliosis and Microgliosis in Mice.

Repeated mild traumatic brain injury (rmTBI) has been identified by epidemiology as a high-risk factor for dementia at a later stage in life. Animal models to replicate complex features of human rmTBI and/or to evaluate long-term effects on brain function have not been established. In this study, we used a novel closed-head impact model of engineered rotational acceleration (CHIMERA) to investigate the long-term neuropathological and cognitive functional consequences of rmTBI. Adult C57BL/6 male mice were subjected to CHIMERA for 3 consecutive days 24 h apart. Functional outcomes were assessed by the beam walk and Morris water maze tests. Neuropathology was evaluated by immunostaining of glial fibrillary acidic protein (GFAP), amyloid precursor protein (APP), and ionizing calcium-binding adaptor molecule-1 (Iba-1), and by quantitative reverse transcription polymerase chain reaction (qRT-PCR) or Western blotting of GFAP, Iba-1, and tumor necrosis factor (TNF)-α. Repeated CHIMERA (rCHIMERA) resulted in motor deficits at 3 days, and in learning and memory impairments that were sustained up to 6 months post injury. GFAP and TNF-α gene expression was increased within a week, whereas astrogliosis and microgliosis were induced starting from day 1 up to 6.5 months after rCHIMERA with upregulated GFAP and Iba-1 protein levels. rCHIMERA also induced APP deposition from day 1 to day 7, but this diminished by 1 month. In conclusion, rCHIMERA produces long-lasting cognitive impairments with astrogliosis and microgliosis in mice, suggesting that rCHIMERA can be a useful animal model to study the long-term complications, as well as the cellular and molecular mechanisms, of human rmTBI.

The Role of Substance P in Pulmonary Clearance of Bacteria in Comparative Injury Models.

Neural input to the immune system can alter its ability to clear pathogens effectively. Patients suffering mild traumatic brain injury (mTBI) have shown reduced rates of pneumonia and a murine model replicated these findings, with better overall survival of TBI mice compared with sham-injured mice. To further investigate the mechanism of improved host response in TBI mice, this study developed and characterized a mild tail trauma model of similar severity to mild TBI. Both mild tail trauma and TBI induced similar systemic changes that normalized within 48 hours, including release of substance P. Examination of tissues showed that injuries are limited to the target tissue (ie, tail in tail trauma, brain in mTBI). Pneumonia challenge showed that mild TBI mice showed improved immune responses, characterized by the following: i) increased survival, ii) increased pulmonary neutrophil recruitment, iii) increased bacterial clearance, and iv) increased phagocytic cell killing of bacteria compared with tail trauma. Administration of a neurokinin-1-receptor antagonist to block substance P signaling eliminated the improved survival of mTBI mice. Neurokinin-1-receptor antagonism did not alter pneumonia mortality in tail trauma mice. These data show that immune benefits of trauma are specific to mTBI and that tail trauma is an appropriate control for future studies aimed at elucidating the mechanisms of improved innate immune responses in mTBI mice.

Treatment with an anti-CD11d integrin antibody reduces neuroinflammation and improves outcome in a rat model of repeated concussion.

BACKGROUND: Concussions account for the majority of traumatic brain injuries (TBI) and can result in cumulative damage, neurodegeneration, and chronic neurological abnormalities. The underlying mechanisms of these detrimental effects remain poorly understood and there are presently no specific treatments for concussions. Neuroinflammation is a major contributor to secondary damage following more severe TBI, and recent findings from our laboratory suggest it may be involved in the cumulative properties of repeated concussion. We previously found that an anti-CD11d monoclonal antibody that blocks the CD11d/CD18 integrin and adhesion molecule interaction following severe experimental TBI reduces neuroinflammation, oxidative activity, and tissue damage, and improves functional recovery. As similar processes may be involved in repeated concussion, here we studied the effects of the anti-CD11d treatment in a rat model of repeated concussion. METHODS: Rats were treated 2 h and 24 h after each of three repeated mild lateral fluid percussion injuries with either the CD11d antibody or an isotype-matched control antibody, 1B7. Injuries were separated by a five-day inter-injury interval. After the final treatment and either an acute (24 to 72 h post-injury) or chronic (8 weeks post-injury) recovery period had elapsed, behavioral and pathological outcomes were examined. RESULTS: The anti-CD11d treatment reduced neutrophil and macrophage levels in the injured brain with concomitant reductions in lipid peroxidation, astrocyte activation, amyloid precursor protein accumulation, and neuronal loss. The anti-CD11d treatment also improved outcome on tasks of cognition, sensorimotor ability, and anxiety. CONCLUSIONS: These findings demonstrate that reducing inflammation after repeated mild brain injury in rats leads to improved behavioral outcomes and that the anti-CD11d treatment may be a viable therapy to improve post-concussion outcomes.

[Expert evaluation of certain immune system disturbances after mild traumatic brain injuries].

The authors present results of evaluation of immune disorders in 47 patients presenting with brain concussion (BC) and in 28 subjects with mild cerebral contusion (MCC). It was shown that in patients of the former group all immune characteristics were totally restored within 3 weeks after the injury. In the latter group, the clinical picture of secondary immunodeficiency with impaired parameters of the immune status persisted for at least 28 days after the injury. It is concluded that the dynamics of immune system disturbances after a traumatic brain injury may be used as an objective criterion for the evaluation of not only the severity of the injury but also of the duration of the recovery period after mild traumatic brain injury.

Variations in the response of interleukins in neurosurgical intensive care patients monitored using intracerebral microdialysis.

OBJECT: The aim of this study was to make a preliminary evaluation of whether microdialysis monitoring of cytokines and other proteins in severely diseased neurosurgical patients has the potential of adding significant information to optimize care, thus broadening the understanding of the function of these molecules in brain injury. METHODS: Paired intracerebral microdialysis catheters with high-cutoff membranes were inserted in 14 comatose patients who had been treated in a neurosurgical intensive care unit following subarachnoidal hemorrhage or traumatic brain injury. Samples were collected every 6 hours (for up to 7 days) and were analyzed at bedside for routine metabolites and later in the laboratory for interleukin (IL)-l and IL-6; in two patients, vascular endothelial growth factor and cathepsin-D were also checked. Aggregated microprobe data gave rough estimations of profound focal cytokine responses related to morphological tissue injury and to anaerobic metabolism that were not evident from the concomitantly collected cerebrospinal fluid data. Data regarding tissue with no macroscopic evidence of injury demonstrated that IL release not only is elicited in severely compromised tissue but also may be a general phenomenon in brains subjected to stress. Macroscopic tissue injury was strongly linked to IL-6 but not IL- lb activation. Furthermore, IL release seems to be stimulated by local ischemia. The basal tissue concentration level of IL-lb was estimated in the range of 10 to 150 pg/ml; for IL-6, the corresponding figure was 1000 to 20,000 pg/ml. CONCLUSIONS: Data in the present study indicate that catheters with high-cutoff membranes have the potential of expanding microdialysis to the study of protein chemistry as a routine bedside method in neurointensive care.

Interleukin-1beta messenger ribonucleic acid and protein levels after fluid-percussion brain injury in rats: importance of injury severity and brain temperature.

OBJECTIVE: Posttraumatic temperature manipulations have been reported to significantly influence the inflammatory response to traumatic brain injury (TBI). The purpose of this study was to determine the temporal and regional profiles of messenger ribonucleic acid (mRNA) expression and protein levels for the proinflammatory cytokine interleukin-1beta (IL-1beta), after moderate or severe TBI. The effects of posttraumatic hypothermia (33 degrees C) or hyperthermia (39.5 degrees C) on these consequences of TBI were then determined. METHODS: Male Sprague-Dawley rats underwent fluid-percussion brain injury. In the first phase of the study, rats were killed 15 minutes or 1, 3, or 24 hours after moderate TBI (1.8-2.2 atmospheres), for reverse transcription-polymerase chain reaction analysis. Other groups of rats were killed 1, 3, 24, or 72 hours after moderate or severe TBI (2.4-2.7 atmospheres), for protein analysis. In the second phase, rats underwent moderate fluid-percussion brain injury, followed immediately by 3 hours of posttraumatic normothermia (37 degrees C), hyperthermia (39.5 degrees C), or hypothermia (33 degrees C), and were then killed, for analyses of protein levels and mRNA expression. Brain samples, including cerebral cortex, hippocampus, thalamus, and cerebellum, were dissected and stored at -80 degrees C until analyzed. RESULTS: The findings indicated that mRNA levels were increased (P < 0.05) as early as 1 hour after TBI and remained elevated up to 3 hours after moderate TBI. Although both moderate and severe TBI induced increased levels of IL-1beta (P < 0.05), increased protein levels were also noted in remote brain structures after severe TBI. Posttraumatic hypothermia attenuated IL-1beta protein levels, compared with normothermia (P < 0.05), although the levels remained elevated in comparison with sham values. In contrast, hyperthermia had no significant effect on IL-1beta levels, compared with normothermic values. Posttraumatic temperature manipulations had no significant effect on IL-1beta mRNA levels. CONCLUSION: Injury severity determines the degree of IL-1beta protein level elevation after TBI. The effects of posttraumatic hypothermia on IL-1beta protein levels (an important mediator of neurodegeneration after TBI) may partly explain the established effects of posttraumatic temperature manipulations on inflammatory processes after TBI.

[Circulating immune complexes in acute concussion of the brain]. / Tsirkuliruiushchie immunnye kompleksy v ostrom periode sotriaseniia golovnogo mozga u detei.

The aim of the study was to study the count of circulating immune complexes (CIC) in the blood of children with acute concussion of the brain. The fact that CIC at high concentrations that can penetrate into the brain through the blood-brain barrier and cause complications as vasculitis, microangiopathy, proliferative processes in the meninges, enlarged ventricles of the brain, and atrophy of its tissue was borne in mind. The studies revealed a significant progressive CIC increase within 3 weeks. For correction of blood CIC levels, laser exposure was applied to the carotid and vertebral arteries and acupuncture points. For comparison, thymaline in age-specific doses was used. Laser radiation showed a significant fall of CIC at days 19-21, particular when applied to the acupuncture points. Thymaline did not affect blood CIC levels. Laser application to the acupuncture points in children with acute brain concussion should reduce the incidence of complications of brain injury disease.

A quantitative immunohistochemical study on the time-dependent course of acute inflammatory cellular response to human brain injury.

The time-dependent inflammatory cell reaction in human cortical contusions has been investigated during the first 30 weeks after blunt head injury. Immunohistochemical staining was carried out using CD 15 for granulocytes and LCA, CD 3 and UCHL-1 for mononuclear leucocytes. In order to provide reliable data for a forensic wound age estimation, the intensity of the cellular reaction was evaluated with a quantitative image analysis system. CD 15-labelled granulocytes were detectable earliest 10 min after brain injury, whereas significantly increased numbers of mononuclear leucocytes occurred in cortical contusions after a postinfliction interval of at least 1.1 days (LCA), 2 days (CD 3) or 3.7 days (UCHL-1), respectively.

Intracerebral inflammation after human brain contusion.

OBJECTIVE: This study was undertaken to analyze the inflammatory components in contused human brain tissue to compare the findings with previous experimental data regarding the pathogenesis of brain contusions. METHODS: Contused brain tissue biopsies were obtained from 12 consecutive patients undergoing surgery for brain contusions 3 hours to 5 days after trauma. Inflammatory and immunological components were analyzed by immunohistochemistry. RESULTS: In patients undergoing surgery less than 24 hours after trauma, the inflammatory response was limited to vascular margination of polymorphonuclear cells. In patients undergoing surgery 3 to 5 days after trauma, however, a massive inflammatory response consisting of monocytes/macrophages, reactive microglia, polymorphonuclear cells, and CD4- and CD8-positive T lymphocytes was detected. Human lymphocyte antigen-DQ was expressed on reactive microglia and infiltrating leukocytes in the late patient group. In addition, CD1a, which is a marker for antigen-presenting dendritic cells, was detected in a subgroup of microglial cells. CONCLUSION: The results corroborated hypotheses derived from experimental data. In the early phase after contusional trauma, inflammation is mainly intravascular and dominated by polymorphonuclear cells. The inflammation was parenchymal in patients undergoing surgery 3 to 5 days after trauma. The brain swelling seemed to be biphasic, the delayed phase correlating with a parenchymal inflammation. The inflammatory cells may produce several potentially harmful effects, such as acute cellular degeneration; they may also lead to degenerative long-term effects.