Experimental Trauma Model Research Articles

Single Versus Repetitive Traumatic Brain Injury: Current Knowledge on the Chronic Outcomes, Neuropathology and the Role of TDP-43 Proteinopathy.

Traumatic brain injury (TBI) is one of the most important causes of death and disability in adults and thus an important public health problem. Following TBI, secondary pathophysiological processes develop over time and condition the development of different neurodegenerative entities. Previous studies suggest that neurobehavioral changes occurring after a single TBI are the basis for the development of Alzheimer's disease, while repetitive TBI is considered to be a contributing factor for chronic traumatic encephalopathy development. However, pathophysiological processes that determine the evolvement of a particular chronic entity are still unclear. Human post-mortem studies have found combinations of amyloid, tau, Lewi bodies, and TAR DNA-binding protein 43 (TDP-43) pathologies after both single and repetitive TBI. This review focuses on the pathological changes of TDP-43 after single and repetitive brain traumas. Numerous studies have shown that TDP-43 proteinopathy noticeably occurs after repetitive head trauma. A relatively small number of available preclinical research on single brain injury are not in complete agreement with the results from the human samples, which makes it difficult to draw specific conclusions. Also, as TBI is considered a heterogeneous type of injury, different experimental trauma models and injury intensities may cause differences in the cascade of secondary injury, which should be considered in future studies. Experimental and post-mortem studies of TDP-43 pathobiology should be carried out, preferably in the same laboratories, to determine its involvement in the development of neurodegenerative conditions after one and repetitive TBI, especially in the context of the development of new therapeutic options.

Ballooned neurons in semi-recent severe traumatic brain injury

Traumatic brain injury (TBI) is now recognized as an insult triggering a dynamic process of degeneration and regeneration potentially evolving for years with chronic traumatic encephalopathy (CTE) as one major complication. Neurons are at the center of the clinical manifestations, both in the acute and chronic phases. Yet, in the acute phase, conventional neuropathology detects abnormalities predominantly in the axons, if one excludes contusions and hypoxic ischemic changes. We report the finding of ballooned neurons, predominantly in the anterior cingulum, in three patients who sustained severe TBI and remained comatose until death, 2 ½ weeks to 2 ½ months after the traumatic impact. All three cases showed severe changes of traumatic diffuse axonal injury in line with acceleration/deceleration forces. The immunohistochemical profile of the ballooned neurons was like that described in neurodegenerative disorders like tauopathies which were used as controls. The presence of αB-crystallin positive ballooned neurons in the brain of patients who sustained severe craniocerebral trauma and remained comatose thereafter has never been reported. We postulate that the co-occurrence of diffuse axonal injury in the cerebral white matter and ballooned neurons in the cortex is mechanistically reminiscent of the phenomenon of chromatolysis. Experimental trauma models with neuronal chromatolytic features emphasized the presence of proximal axonal defects. In our three cases, proximal swellings were documented in the cortex and subcortical white matter. This limited retrospective report should trigger further studies in order to better establish, in recent/semi-recent TBI, the frequency of this neuronal finding and its relationship with the proximal axonal defects.

Experimental Substantiation of Autoplasma Application as a Haemostatic Agent in Endoscopic Operations in the Digestive Tract

Abstract In endosurgery of the digestive tract, ‘cellular technologies’ are gaining popularity, including the use of blood components or blood cells with a haemostatic purpose. In this regard, the objective of the study is evaluation of the effectiveness of bleeding control and safety of resection of the hollow organs of the digestive tract in the experimental trauma models of the abdominal organs in laboratory animals. The study was conducted in 20 mature male Chinchilla rabbits with the mean body mass of 2450 ± 210 g. All animals were divided into four experimental groups: the control group (without bleeding control); the group that received the infiltration of the wall of a hollow organ with saline; the group in which bleeding was controlled by argon plasma coagulation (APC), and the group wherein animals underwent haemostasis with autoplasma. In the control group and the physiological saline group, no statistical difference was observed in the time of bleeding control. Autoplasma, due to preventive local administration, is more effective than APC and has a high haemostatic potential. Autoplasma has been found to be highly effective and safe for bleeding control in the gastrointestinal tract in the experimental model, which has paved the way for new possibilities for operations of various scales, including endoscopic operations.

Platelet dysfunction after trauma: From mechanisms to targeted treatment.

Platelet dysfunction after trauma: From mechanisms to targeted treatment.

Effect of antisecretory factor, given as a food supplement to adult patients with severe traumatic brain injury (SASAT): protocol for an exploratory randomized double blind placebo-controlled trial

BackgroundTraumatic brain injury (TBI) constitutes a global epidemic. Overall outcome is poor, with mortality ranging from 10 to 70% and significant long-term morbidity. Several experimental reports have claimed effect on traumatic edema, but no clinical trials have shown effect on edema or outcome. Antisecretory factor, an endogenous protein, is commercially available as Salovum®, which is classified as a medical food by the European Union and has shown effect in experimental trauma models and feasibility with signs of effect in 2 pilot case series. The aim of this study is to assess the effect of antisecretory factor in adult patients with severe traumatic brain injury as measured by 30-day mortality, treatment intensity level (TIL), and intracranial pressure (ICP).Methods/designThis is a single-center, double-blind, randomized, placebo-controlled clinical phase 2 trial, investigating the clinical superiority of Salovum® given as a food supplement to adults with severe TBI (GCS < 9), presenting to the trauma unit at Tygerberg University Hospital, Cape Town, South Africa, that are planned for invasive ICP monitoring and neurointensive care, will be screened for eligibility, and assigned to either treatment group (n = 50) or placebo group (n = 50). In both groups, the primary outcome will be 30-day mortality, recorded via hospital charts, follow-up phone calls, and the population registry. Secondary outcomes will be treatment intensity level (TIL), scored from hospital charts, and ICP registered from hospital data monitoring.Trial registrationClinicalTrials.gov NCT03339505. Registered on September 17, 2017.Protocol version 3.0 from November 13, 2020

Autoplasma as a Hemostatic Agent for Endoscopic Surgery of Hollow Organs

Introduction. To maximize the effectiveness of hemostatic technologies, it is necessary to optimize local hemostasis through hybrid and controlled approaches, as well as to improve the conditions for tissue surgical dissection preventing perforation of hollow organs. This study is aimed at assessing the efficacy of stopping bleeding and the safety of resection of digestive hollow organs in experimental models of trauma to abdominal organs in laboratory animals.Materials and methods. Experiments were carried out in vivo on 20 rabbits. All animals were divided into 4 experimental groups (5 animals each): I — the control group, in which no methods for stopping bleeding were used; II — the group, in which infiltration of the wall of a hollow organ with saline solution was used; III — the group, in which physical hemostasis was applied using an electrosurgical unit and an argon plasma coagulation apparatus; IV — the group, animals in which underwent controlled local biological hemostasis using autoplasma. Prior to laparotomy, 2–3 ml of whole blood was taken from the rabbit’s ear for preliminary preparation of autoplasma. The prepared autoplasma was introduced into the area of resection or other operation of the mucous membrane of the rabbit’s digestive tract.Results and discussion. Although no statistical difference in the time of stopping bleeding was observed between the control (I) and saline (II) groups, one more episode of bleeding was noted in group II. Preventive local administration of autoplasma (group IV) was established to have a high hemostatic potential. As expected, electrocoagulation was more effective than saline; however, hemostasis achieved by means of argon plasma coagulation is characterized by rapid formation of a necrotic zone, which may lead to undesirable consequences in the long-term period.Conclusion. Preventive local administration of autoplasma and recombinant human protein has a high hemostatic potential in animals. In comparison, electrocoagulation is less effective due to the rapid filling of the pathological focus with blood.

Experimental Substantiation of Autoplasma Application as a Haemostatic Agent in Endoscopic Operations in the Digestive Tract

Abstract Introduction. In endosurgery of the digestive tract, ‘cellular technologies’ are gaining popularity, including the use of blood components or blood cells with a haemostatic purpose. In this regard, the objective of the study is evaluation of the effectiveness of bleeding control and safety of resection of the hollow organs of the digestive tract in the experimental trauma models of the abdominal organs in laboratory animals. Materials and methods. The study was conducted in 20 mature male Chinchilla rabbits with the mean body mass of 2450 ± 210 g. All animals were divided into four experimental groups: the control group (without bleeding control); the group that received the infiltration of the wall of a hollow organ with saline; the group in which bleeding was controlled by argon plasma coagulation (APC), and the group wherein animals underwent haemostasis with autoplasma. Results. In the control group and the physiological saline group, no statistical difference was observed in the time of bleeding control. Autoplasma, due to preventive local administration, is more effective than APC and has a high haemostatic potential. Conclusion. Autoplasma has been found to be highly effective and safe for bleeding control in the gastrointestinal tract in the experimental model, which has paved the way for new possibilities for operations of various scales, including endoscopic operations.

The effect of ferulic acid on experimental traumatic brain damage in rats.

Traumatic brain injury is an important social health problem due to the fact that young adults are more likely to be affected, and advanced functional limitations are observed in survivors. In this study, we aimed to investigate the protective effect of ferulic acid in an experimental trauma model. This study was performed in March 2016 at Dokuz Eylül University Experimental Animal Laboratory. Subjects were randomly divided into 4 groups Control, Ethyl Alcohol, Trauma, Trauma/Ferulic Acid groups. For histological findings, Cresyl violet; for immunohistochemical analysis, TUNEL and Active Caspase-3 staining were used. For biochemical analysis, Superoxide dismutase, Malondialdehyde, and Glutathione values ​​were examined. The application of ferulic acid has been shown to primarily reduce neuronal apoptosis, the levels of free radicals, and to effect oxidant/antioxidant balance positively by increasing the levels of antioxidants, such as Superoxide dismutase and Glutathione that are developed due to brain damage. Our study group has shown that ferulic acid decreased nerve tissue pathologies after generated brain trauma compared to injury groups. Addition of ferulic acid to the traditional head trauma treatment has the strength, and ability to increase the rate, and percentage of healing (Tab. 2, Fig. 4, Ref. 28).

Induction of salivary nerve growth factor by Yogic breathing: a randomized controlled trial

Nerve growth factor (NGF), a trophic factor involved in the development, maintenance, and survival of the peripheral nervous system and the cholinergic neurons of the central nervous system, is significantly reduced in Alzheimer's Disease (AD) patients (Aloe et al., 2012). Particularly basal forebrain complex (BFC) neurons are highly affected in AD patients. NGF protects BFC neurons in experimental trauma models and in age-associated cholinergic decline. Therefore, administration of NGF is investigated as a therapeutic option for AD patients (Aloe et al., 2012). NGF therapy is limited by hyperalgesia, limited bioavailability, and use of invasive methods including intracranial injection of adeno-associated virus-based gene delivery vector, which constitutively expresses human NGF. In this context, non-pharmacological modes of treatment such as meditation and Yoga have been considered as alternative approaches to treat neurological disorders. Yogic breathing (YB, also called Pranayama) is a collection of techniques to regulate breathing voluntarily. YB induces a strong relaxation response via vagal and parasympathetic stimulation (Jerath et al., 2006). Such responses are causally linked to rapid changes in gene expression, particularly to those genes controlling stress, inflammation, and metabolism. Saliva is a known source of NGF, and incidentally, Yoga and relaxation stimulate salivation. Saliva (0.75–1.5 L/day in humans) contains numerous biologically active molecules to be potentially useful as diagnostic markers and as therapeutic clues. Salivary secretion regulates the digestive, nervous, immune, and respiratory systems. We conducted a pilot study to investigate whether YB could potentially stimulate salivary expression of NGF in cognitively normal healthy volunteers. This could serve as a model for future studies in AD patients.

N‐methyl‐D‐aspartate preconditioning improves short‐term motor deficits outcome after mild traumatic brain injury in mice

Traumatic brain injury (TBI) causes impairment of fine motor functions in humans and nonhuman mammals that often persists for months after the injury occurs. Neuroprotective strategies for prevention of the sequelae of TBI and understanding the molecular mechanisms and cellular pathways are related to the glutamatergic system. It has been suggested that cellular damage subsequent to TBI is mediated by the excitatory neurotransmitters, glutamate and aspartate, through the excessive activation of the N-methyl-D-aspartate (NMDA) receptors. Thus, preconditioning with a low dose of NMDA was used as a strategy for protection against locomotor deficits observed after TBI in mice. Male adult mice CF-1 were preconditioned with NMDA (75 mg/kg) 24 hr before the TBI induction. Under anesthesia with O(2)/N(2)O (33%: 66%) inhalation, the animals were subjected to the experimental model of trauma that occurs by the impact of a 25 g weight on the skull. Sensorimotor gating was evaluated at 1.5, 6, or 24 hr after TBI induction by using footprint and rotarod tests. Cellular damage also was assessed 24 hr after occurrence of cortical trauma. Mice preconditioned with NMDA were protected against all motor deficits revealed by footprint tests, but not those observed in rotarod tasks. Although mice showed motor deficits after TBI, no cellular damage was observed. These data corroborate the hypothesis that glutamatergic excitotoxicity, especially via NMDA receptors, contributes to severity of trauma. They also point to a putative neuroprotective mechanism induced by a sublethal dose of NMDA to improve motor behavioral deficits after TBI.

ATLS(R) and damage control in spine trauma.

Substantial inflammatory disturbances following major trauma have been found throughout the posttraumatic course of polytraumatized patients, which was confirmed in experimental models of trauma and in vitro settings. As a consequence, the principle of damage control surgery (DCS) has developed over the last two decades and has been successfully introduced in the treatment of severely injured patients. The aim of damage control surgery and orthopaedics (DCO) is to limit additional iatrogenic trauma in the vulnerable phase following major injury. Considering traumatic brain and acute lung injury, implants for quick stabilization like external fixators as well as decided surgical approaches with minimized potential for additional surgery-related impairment of the patient's immunologic state have been developed and used widely. It is obvious, that a similar approach should be undertaken in the case of spinal trauma in the polytraumatized patient. Yet, few data on damage control spine surgery are published to so far, controlled trials are missing and spinal injury is addressed only secondarily in the broadly used ATLS® polytrauma algorithm. This article reviews the literature on spine trauma assessment and treatment in the polytrauma setting, gives hints on how to assess the spine trauma patient regarding to the ATLS® protocol and recommendations on therapeutic strategies in spinal injury in the polytraumatized patient.

Glutathione peroxidase overexpression does not rescue impaired neurogenesis in the injured immature brain.

Traumatic brain injury (TBI) is a leading cause of disability among young children and is associated with long-term cognitive deficits. These clinical findings have prompted an investigation of the hippocampus in an experimental model of trauma to the developing brain at postnatal day (p21). Previous studies using this model have revealed a progressive loss of neurons in the hippocampus as brain-injured animals mature to young adulthood. Here we determined whether this hippocampal vulnerability is likewise reflected in altered neurogenesis and whether the antioxidant glutathione peroxidase (GPx) modulates neurogenesis during maturation of the injured immature brain. Male transgenic mice that overexpress GPx and wild-type littermates were subjected to controlled cortical impact or sham surgery on p21. At 2 weeks postinjury, the numbers of proliferating cells and immature neurons within the subgranular zone were measured by using Ki-67 and doublecortin, respectively. Bromodeoxyuridine (BrdU) was used to label dividing cells beginning 2 weeks postinjury. Survival (BrdU(+)) and neuronal differentiation (BrdU(+)/NeuN(+)) were then measured 4 weeks later via confocal microscopy. Two-way ANOVA revealed no significant interaction between genotype and injury. Subsequent analysis of the individual effects of injury and genotype, however, showed a significant reduction in subgranular zone proliferation (Ki-67) at 2 weeks postinjury (P = 0.0003) and precursor cell survival (BrdU(+)) at 6 weeks postinjury (P = 0.016) and a trend toward reduced neuronal differentiation (BrdU(+)/NeuN(+)) at 6 weeks postinjury (P = 0.087). Overall, these data demonstrate that traumatic injury to the injured immature brain impairs neurogenesis during maturation and suggest that GPx cannot rescue this reduced neurogenesis.

N-6 polynsaturated fatty acids confer hemodynamic stability in an experimental model of multiple trauma

Immunonutrition with diets enriched in polyunsaturated fatty acids (PUFAs) are becoming mandatory for multiple trauma patients. Solutions containing single n-6 PUFAs were administered intravenously in an experimental model of trauma. Thirty-five rabbits were studied; 13 controls; 10 administered gamma-linolenic acid (GLA) 30 min after fracture of the right femor; and 12 arachidonic acid (AA). Systolic, diastolic and mean arterial pressures and heart rate were recorded; serum levels of tumor necrosis factor-alpha (TNF α), malondialdehyde (MDA) and nitrate were estimated before and after therapy. Mean survival of controls, of animals treated with GLA and of animals treated with AA was 0.80, 1.41 and 3.60 days, respectively. Administration of PUFAs induced higher levels of blood pressure; that of AA decreased serum TNF α and tissue bacterial load compared to controls. Intravenous administration of n-6 PUFAs conferred hemodynamic stability and increased survival in a model of trauma rendering further research mandatory.

α-Internexin immunoreactivity reflects variable neuronal vulnerability in Alzheimer's disease and supports the role of the β-amyloid plaques in inducing neuronal injury

This study investigated the role of alpha-internexin in the neuronal alterations associated with beta-amyloid plaque formation in Alzheimer's disease (AD). Cortical neurons could be defined by their variable content of neurofilament (NF) triplet and alpha-internexin proteins, with a distinct population of supragranular pyramidal cells containing alpha-internexin alone. Both NF triplet and alpha-internexin were localized to reactive axonal structures in physically damaged neurons in experimental trauma models. Similarly, NF triplet and alpha-internexin immunoreactive neurites were localized to plaques densely packed with beta-amyloid fibrils in preclinical AD cases, indicating that certain plaques may cause structural injury or impediment of local axonal transport. However, alpha-internexin, and not NF triplet, ring-like reactive neurites were present in end-stage AD cases, indicating the relatively late involvement of neurons that selectively contain alpha-internexin. These results implicate the expression of specific intermediate filament proteins in a distinct hierarchy of differential neuronal vulnerability to AD.

A model for studies of intracranial volume pressure dynamics in traumatic brain injury.

The present study was undertaken to establish an experimental trauma model where it was possible to alter intracranial pressure (ICP) dynamics without raising intracranial pressure to abnormal levels and monitor metabolic disturbances with microdialysis. Thirty rats were intubated and mechanically ventilated before and after trauma. ICP was measured in the left ventricle. A weight-drop technique (21 g from 35 cm) with a brain compression of 1.5 mm was used to produce the injury. Intracranial compensatory volume was decreased 20 or 60 microL by placement of rubber film between the dura mater and bone. A bolus injection technique was used for the pressure volume response. ICP remained within normal limits for 2 h after trauma irrespective of the reduction in compensatory intracranial volume. Pressure-volume index decreased from 0.0825 +/- 0.009 to 0.0779 +/- 0.011 mL in the sham trauma and from 0.0871 +/- 0.018 to 0.0748 +/- 0.017 mL in the trauma groups (p < 0.015) when the intracranial volume was reduced by 60 microL. Intracranial compliance was not affected significantly. The present study shows that it is possible to vary ICP dynamics in a traumatic brain injury model without causing pathological increases in baseline ICP. This model may be used to study the effects of secondary insults (i.e., hypotension, hypoxia, hypercarbia, and hyperthermia) on the injured brain when ICP is normal but intracranial compensatory volume is impaired.

Gas tonometry for evaluation of gastrointestinal mucosal perfusion: experimental models of trauma, shock and complex surgical maneuvers - Part 1

Substantial clinical and animal evidences indicate that the mesenteric circulatory bed, particularly the gut mucosa, is highly vulnerable to reductions in oxygen supply and prone to early injury in the course of hemodynamic changes induced by trauma, shock, sepsis and several complex surgical maneuvers. Gut hypoxia or ischemia is one possible contributing factor to gastrointestinal tract barrier dysfunction that may be associated with the development of systemic inflammatory response and multiple organ dysfunction syndrome, a common cause of death after trauma, sepsis or major surgeries. Monitoring gut perfusion during experiments may provide valuable insights over new interventions and therapies highly needed to reduce trauma and sepsis-related morbidity and mortality. We present our experience with gas tonometry as a monitor of the adequacy of gastrointestinal mucosal perfusion in clinical and experimental models of trauma, shock and surgical maneuvers associated with abrupt hemodynamic changes, such as aortic occlusion and hepatic vascular exclusion. Next issue we will be presenting our experience with gas tonometry in experimental and clinical sepsis.

INTRAOPERATIVE USE OF THE ABSORBABLE FIBRIN ADHESIVE BANDAGE: LONG TERM EFFECTS

The absorbable fibrin adhesive bandage (AFAB) reduces acute blood loss in experimental trauma models, but the effects on wound healing and subsequent function have heretofore not been investigated. Retropubic prostatectomy was selected to evaluate short and long term effects of using the AFAB intraoperatively. Dogs undergoing prostatectomy were randomly assigned to one of four treatments: CONTROL- sponges and manual pressure were applied after transecting the prostatic pedicles. Sponges were removed when the prostate was delivered. Vessels were isolated and ligated if bleeding continued after removal. AFAB- hemostatically active bandages were applied to the prostatic bed prior to sponges and pressure. Additional bandages were applied at the urethrovesical junction after completing the anastomosis. PLACEBO- visually identical (hemostatically inert) bandages were applied in an identical fashion. LIQUID SEALANT- concentrated thrombin and fibrinogen solution was applied to the vessels prior to sponges and pressure. Additional sealant solution was applied around the anastomosis. Blood loss and time to achieve hemostasis were significantly less in the AFAB group compared with the other treatments. There were no differences in days to anastomotic integrity, continence, or intra-abdominal adhesions at necropsy six weeks later. The AFAB can reduce surgery time and blood loss, with no decrement in wound healing or subsequent function.

Differences in mechanical response between fractured and non-fractured spines under high-speed impact

Objective. The differences in mechanical response between fractured and non-fractured spines were investigated using a porcine spine impact model. Design. Ten three-vertebrae segments (C3–C5) of porcine spine were subjected to a single impact to study the trauma mechanism. Small steel balls glued to the vertebra and a high-speed camera were used to observe the deformation of vertebral body and disc during impact. After trauma, the episodes of fractured specimens were compared with those of non-fractured specimens. Background. Experimental trauma models using the spines of mature animals have rarely been evaluated. Finding a well-controlled, reproducible protocol based on an easily accessible specimen was therefore important. These models will be promising if clinical fractures can be produced. Methods. All of the specimens were subjected to high-speed flexion-compression loading. The impact to the load cell and the operation of the high-speed camera were synchronized. The force-time sequence and disc deformation curve were recorded. The results from fractured and non-fractured spines were then compared. Results. There were three burst fractures, four pedicle fractures, one facet joint fracture, one compression fracture and one fracture-dislocation. All of these fractures were similar to clinical fractures. Compared to non-fractured specimens, the fractured specimens had lower maximal force and longer reaction time. The characteristic steep decline in the middle region of the force-time curve was also consistently noted in the fractured spines. Conclusions. Spinal fractures similar to those found clinically were successfully produced in porcine spines. The characteristics of the mechanical responses observed should be helpful in the interpretation of events which occur during impact.

Metabolic response to experimental trauma: the time relation of post-traumatic protein metabolism

The relationship between time and the post-traumatic metabolic response was studied in a commonly used experimental model of trauma. Twenty nine rats underwent laparotomy and jugular vein sham catheterization as the standard trauma. The rats were fed ad libitum and compared to pair fed controls in terms of nitrogen balance and liver protein synthesis. The pairs of rats were divided into three groups according to the duration of the experiment, which was 24 h, 48 h or72 h. The nitrogen balance was calculated daily and the liver protein synthesis in vitro measured in 10 rats after 48 h with an asanguinous perfusion system using L-(1-C 14)-Leucine. The metabolic effect of trauma was first detected in liver protein synthesis, which was diminished in the early post-traumatic period ( percentage synthesis rates: post-traumatic 34.6 ± 10.7 and pair fed 60.4 ± 21.3, Mean ± SD, P < 0.05). During this period the whole body nitrogen balances were similar (post-traumatic −1.200 ± 1.440 and pair fed −0.880 ± 1.130, gN/kg/48 h, mean ± SD). On the third day, the response to nitrogen intake and the nitrogen balance became significantly worse in the post-traumatic rats (post-traumatic 0.214 ± 1.680 and pair fed 1.236 ± 1.220, gN/kg/day, mean ± SD). These observations suggest that, firstly, the ‘flow’ phase has its onset on the third post-trauma day, and secondly that trauma does decrease liver protein synthesis, and this decrease lasts at least through the ‘ebb’ phase. The results indicate the necessity of defining the metabolic phase in experimental studies of post-traumatic metabolism.