Ultrastructure Of Brain Tissue Research Articles

Synergistic promotion of angiogenesis after intracerebral hemorrhage by ginsenoside Rh2 and chrysophanol in rats

BackgroundIntracerebral hemorrhage (ICH) is a debilitating condition characterized by the rupture of cerebral blood vessels, resulting in profound neurological deficits. A significant challenge in the treatment of ICH lies in the brain's limited capacity to regenerate damaged blood vessels. This study explores the potential synergistic effects of Ginsenoside Rh2 and Chrysophanol in promoting angiogenesis following ICH in a rat model. MethodsNetwork pharmacology was employed to predict the potential targets and pathways of Ginsenoside Rh2 and Chrysophanol for ICH treatment. Molecular docking was utilized to assess the binding affinity between these compounds and their respective targets. Experimental ICH was induced in male Sprague-Dawley rats through stereotactic injection of type VII collagenase into the right caudate putamen (CPu). The study encompassed various methodologies, including administration protocols, assessments of neurological function, magnetic resonance imaging, histological examination, observation of brain tissue ultrastructure, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), immunofluorescence staining, Western blot analysis, and statistical analyses. ResultsNetwork pharmacology analysis indicated that Ginsenoside Rh2 and Chrysophanol may exert their therapeutic effects in ICH by promoting angiogenesis. Results from animal experiments revealed that rats treated with Ginsenoside Rh2 and Chrysophanol exhibited significantly improved neurological function, reduced hematoma volume, and diminished pathological injury compared to the Model group. Immunofluorescence analysis demonstrated enhanced expression of vascular endothelial growth factor receptor 2 (VEGFR2) and CD31, signifying augmented angiogenesis in the peri-hematomal region following combination therapy. Importantly, the addition of a VEGFR2 inhibitor reversed the increased expression of VEGFR2 and CD31. Furthermore, Western blot analysis revealed upregulated expression of angiogenesis-related factors, including VEGFR2, SRC, AKT1, MAPK1, and MAPK14, in the combination therapy group, but this effect was abrogated upon VEGFR2 inhibitor administration. ConclusionThe synergistic effect of Ginsenoside Rh2 and Chrysophanol demonstrated a notable protective impact on ICH injury in rats, specifically attributed to their facilitation of angiogenesis. Consequently, this research offers a foundation for the utilization of Ginsenosides Rh2 and Chrysophanol in medical settings and offers direction for the advancement of novel pharmaceuticals for the clinical management of ICH.

A cost-effective and efficient ex vivo, ex situ human whole brain perfusion protocol for immunohistochemistry

BackgroundChemical fixation of the brain can be executed through either the immersion method or the perfusion method. Perfusion fixation allows for better preservation of the brain tissue's ultrastructure, as it provides rapid and uniform delivery of the fixative to the tissue. Still, not all facilities have the expertise to perform perfusion fixation, with initial high cost and complexity of perfusion systems as the main factors limiting its widespread usage. New methodHere we present our low-cost approach of whole brain ex situ perfusion fixation to overcome the aforementioned limitations. Our self-made perfusion system, constructed utilising commercially accessible and affordable medical resources alongside laboratory and everyday items, demonstrates the capability to generate superior histological stainings of brain tissue. The perfused tissue can be stored prior to proceeding with IHC for at least one year. ResultsOur method yielded high-quality results in histological stainings using both free-floating cryosections and paraffin-embedded tissue sections. The system is fully reusable and complies with the principles of sustainable management. Comparison with existing methodsOur whole brain perfusion system has been assembled from simple components and is able to achieve a linear flow with a pressure of 70 mmHg corresponding to the perfusion pressure of the brain. ConclusionsOur ex situ method can be especially useful in research settings where expensive perfusion systems are not affordable or in any field with high time pressure, making it suitable for the field of forensic medicine or pathology in general.

Rhizopus arrhizus infection in mice causes brain histopathological alterations and exacerbates neuronal apoptosis

Rhizopus arrhizus is a fungus that can cause central nervous system infections in animals, resulting in high morbidity and mortality, but the mechanism of injury is rarely reported. In this study, we investigated the mechanism of Rhizopus arrhizus damage to the central nervous system of mice by observing the clinical neurological symptoms and resolving the pathological changes in the ultrastructure of brain tissues, combined with the alteration of apoptosis-related genes and immunohistochemistry (IHC). The results showed that all the mice in the treated group died, the brain pyknosis of neurons, there were black mycelium aggregates around the blood vessels, and apoptotic vesicles were produced. The RT-qPCR results showed that, compared with the control group, the relative transcriptome levels of Caspase 8 and BcL-2 genes were significantly increased (P < 0.05), the relative transcriptome level of Caspase 9 gene was highly significant (P < 0.01), the relative transcriptome level of Caspase 3 and Bax gene was significantly decreased (P < 0.05), and the ratio of Bcl-2/Bax was significantly increased (P < 0.05) in the brains of the treated group. TUNEL staining showed that the rate of neuronal apoptosis in the treated group of mice was extremely significantly higher than that in the control group (P < 0.01). This study shows that Rhizopus arrhizus strain XMLO1 causes brain damage by triggering neuronal apoptosis. This study provided a theoretical basis for revealing the mechanism of Rhizopus arrhizus infection.

Формування ультраструктурних адаптивних реакцій у тканинах організму при експериментальному паркінсонізмі

We studied changes in the ultrastructure of brain tissues - medulla oblongata and striatum, as well as lung and heart tissues in experimental parkinsonism caused by the action of rotenone, which was administered once or for 2 weeks. It has been shown that during the development of a Parkinson-like state the ultrastructure of tissues disturbance, the development of mitochondrial and endothelial dysfunction is observed not only in parts of the brain, but also in other tissues of the body. Mitochondrial dysfunction is significantly expressed in the medulla oblongata, as evidenced by, firstly, a decrease in the total number of mitochondria by 35.7%, and secondly, damage to their ultrastructure in more than 40% of organelles. Endothelial dysfunction was indicated by hyperhydration of the blood-brain barrier. In the tissue of the striatum, the indicated changes were insignificant, instead, a compensatory restoration of dynamic processes in the mitochondrial apparatus, in particular fission-fusion processes, was observed. In the myocardium, there were also significant changes in the ultrastructure, this indicated the development of both mitochondrial and endothelial dysfunctions. As well as in the medulla oblongata tissue, about 40% of mitochondria were found to be damaged, although it should be noted that although not pronounced, but still reliable (by 12.6%) activation of mitochondrial morphogenesis was observed. The histohematal barrier, in particular its endothelial layer, thinned due to destructive processes. Violations of the ultrastructure were also observed in the lung tissue. Significant changes in the mitochondrial apparatus with damage to the mitochondrial structure were revealed. However, the percentage of structurally damaged organelles was significantly (almost 2 times) lower than in the myocardium (reached only 25%). The thickness of the endothelial layer of the air barrier increased by an average of 30%. In tissues where mitochondrial and endothelial dysfunction were less pronounced during longterm administration of rotenone, adaptive changes begin to form, which are probably also observed in people with Parkinson’s disease, which enables them to adapt to the existing disease.

The protective effect of low-dose minocycline on brain microvascular ultrastructure in a rodent model of subarachnoid hemorrhage

The multifaceted nature of subarachnoid hemorrhage (SAH) pathogenesis is poorly understood. To date, no pharmacological agent has been found to be efficacious for the prevention of brain injury when used for acute SAH intervention. This study was undertaken to evaluate the beneficial effects of low-dose neuroprotective agent minocycline on brain microvascular ultrastructures that have not been studied in detail. We studied SAH brain injury using an in vivo prechiasmatic subarachnoid hemorrhage rodent model. We analyzed the qualitative and quantitative ultrastructural morphology of capillaries and surrounding neuropil in the rodent brains with SAH and/or minocycline administration. Here, we report that low-dose minocycline (1 mg/kg) displayed protective effects on capillaries and surrounding cells from significant SAH-induced changes. Ultrastructural morphology analysis revealed also that minocycline stopped endothelial cells from abnormal production of vacuoles and vesicles that compromise blood–brain barrier (BBB) transcellular transport. The reported ultrastructural abnormalities as well as neuroprotective effects of minocycline during SAH were not directly mediated by inhibition of MMP-2, MMP-9, or EMMPRIN. However, SAH brain tissue treated with minocycline was protected from development of other morphological features associated with oxidative stress and the presence of immune cells in the perivascular space. These data advance the knowledge on the effect of SAH on brain tissue ultrastructure in an SAH rodent model and the neuroprotective effect of minocycline when administered in low doses.

Preservation of neurons in an AD 79 vitrified human brain.

Detecting the ultrastructure of brain tissue in human archaeological remains is a rare event that can offer unique insights into the structure of the ancient central nervous system (CNS). Yet ancient brains reported in the literature show only poor preservation of neuronal structures. Using scanning electron microscopy (SEM) and advanced image processing tools, we describe the direct visualization of neuronal tissue in vitrified brain and spinal cord remains which we discovered in a male victim of the AD 79 eruption in Herculaneum. We show exceptionally well preserved ancient neurons from different regions of the human CNS at unprecedented resolution. This tissue typically consists of organic matter, as detected using energy-dispersive X-ray spectroscopy. By means of a self-developed neural image processing network, we also show specific details of the neuronal nanomorphology, like the typical myelin periodicity evidenced in the brain axons. The perfect state of preservation of these structures is due to the unique process of vitrification which occurred at Herculaneum. The discovery of proteins whose genes are expressed in the different region of the human adult brain further agree with the neuronal origin of the unusual archaeological find. The conversion of human tissue into glass is the result of sudden exposure to scorching volcanic ash and the concomitant rapid drop in temperature. The eruptive-induced process of natural vitrification, locking the cellular structure of the CNS, allowed us to study possibly the best known example in archaeology of extraordinarily well-preserved human neuronal tissue from the brain and spinal cord.

Time-effect relationship of acupuncture on histopathology, ultrastructure, and neuroethology in the acute phase of cerebral hemorrhage.

Many clinical studies have addressed the treatment of acute cerebral hemorrhage using acupuncture. However, few studies have examined the relationship between time of acupuncture and curative effect on cerebral hemorrhage. By observing the effect of acupuncture on changes in histopathology, ultrastructure, and neuroethology in a cerebral hemorrhage model of rats, we have directly examined the time-effect relationship of acupuncture. The rat model of cerebral hemorrhage was produced by slowly injecting autologous blood to the right caudate nucleus. The experimental groups were: 3-, 9-, 24-, and 48-hour model groups; and 3-, 9-, 24-, and 48-hour acupuncture groups. The sham-operation group was used for comparison. Acupuncture was performed at the Neiguan (PC6) and Renzhong (DU26) acupoints, twice a day, 6 hours apart, for 5 consecutive days. Brain tissue changes were observed by light microscopy and transmission electron microscopy. Neuroethology was assessed using Bederson and Longa scores. Our results show that compared with the sham-operation and model groups, Bederson and Longa scores were lower in each acupuncture group, with visibly improved histopathology and brain tissue ultrastructure. Further, the results were better in the 3- and 9-hour acupuncture groups than the 24- and 48-hour acupuncture groups. Our findings show that acupuncture treatment can relieve pathological and ultrastructural deterioration and neurological impairment caused by the acute phase of cerebral hemorrhage, and may protect brain tissue during this period. In addition, earlier acupuncture intervention following cerebral hemorrhage (by 3 or 9 hours) is associated with a better treatment outcome.

Effect of dexmedetomidine pretreatment on contents of glutamic acid and γ-aminobutyric acid dur-ing focal cerebral ischemia-reperfusion in rats

Objective To evaluate the effect of dexmedetomidine pretreatment on contents of glutamic acid and γ-aminobutyric acid during focal cerebral ischemia-reperfusion (I/R) in rats. Methods Thirty-six clean-grade healthy male Wistar rats, aged 10 months, weighing 250-300 g, were divided into 3 groups using a random number table method: sham operation group (group S), I/R group, and dexmedetomidine group (group D). Focal cerebral I/R was induced by occlusion of the left middle cerebral artery for 30 min followed by reperfusion in anesthetized rats.The left middle cerebral artery was only isolated but not occluded in group S. Sterile normal saline 1 ml was intraperitoneally injected, and 30 min later the model of focal cerebral I/R was established in group I/R.Rats were sacrificed at the end of reperfusion, and brains were removed for determination of contents of glutamic acid and γ-aminobutyric acid in brain tissues and for examination of ultrastructure (with an electron microscope). Results Compared with group S, the content of glutamic acid was significantly increased, and the content of γ-aminobutyric acid was decreased in I/R and D groups (P<0.05). Compared with group I/R, the content of glutamic acid was significantly decreased, and the content of γ-aminobutyric acid was increased in group D (P<0.05). The damage to the ultrastructure of brain tissues was significantly attenuated in group D when compared with group I/R. Conclusion Dexmedetomidine pretreatment can reduce focal cerebral I/R injury through decreasing the content of glutamic acid and increasing the content of γ-aminobutyric acid in rats. Key words: Dexmedetomidine; Brain; Reperfusion injury; Glutamic acid; gamma-Aminobutyric acid

Expression of aquaporin 4 in contused brain tissue and its relationship with brain edema

Objective To observe the expression of aquaporin 4 (AQP-4) in contused brain tissue and its relationship with brain edema following brain trauma. Methods A retrospective case control analysis was made on 42 patients with severe brain trauma admitted from January 2015 to March 2016. There were 23 males and 19 females, aged from 23 to 62 years [(35.5±5.6)years]. Glasgow coma score (GCS) was 3-5 points in 7 patients, 6-8 points in 23 and 9-10 points in 12. Brain tissue removed from the area 1 cm near the contusion during the cranial surgery were allocated to study group (n=42), while brain tissue removed far from the contusion after internal decompression were used as control (n=8). Ultrastructure of brain tissues was observed under electron microscope. Water content of brain tissue was measured by dry-wet weight method and expression of AQP-4 was measured by immunohistochemical method at postinjury hours 96. Results Morphology and structure of brain tissue in control group were normal. Whereas in study group, the intracellular and interstitial edema were obvious and morphological structure were damaged. Water content and AQP-4 expression in control group showed no obvious increase after operation(73.55±0.10, 0.193±0.016). Water content in study group increased significantly compared to control group and reached the peak value (81.28±0.56) at postinjury 24-72 hours (P<0.01). AQP-4 expression in study group increased at postinjury 6 hours (0.242±0.023) and reached a peak at postinjury 24-72 hours (0.338±0.013), with significant difference compared to control group (P<0.05). Correlation analysis showed change of brain water content was positively correlated with expression level of AQP-4 (r=0.931, P<0.01). Conclusion Expression of AQP-4 in the injured area of brain trauma is significantly increased along with the increase of water content, suggests that the upregulation of AQP-4 plays an important role in traumatic brain edema. Key words: Craniocerebral trauma; Brain edema; Aquaporin 4; Ultrastructure

Neuroprotective effect of Shenqi Fuzheng injection pretreatment in aged rats with cerebral ischemia/reperfusion injury.

Shenqi Fuzheng injection is extracted from the Chinese herbs Radix Astragali and Radix Codonopsis. The aim of the present study was to investigate the neuroprotective effects of Shenqi Fuzheng injection in cerebral ischemia and reperfusion. Aged rats (20-22 months) were divided into three groups: sham, model, and treatment. Shenqi Fuzheng injection or saline (40 mL/kg) was injected into the tail vein daily for 1 week, after which a cerebral ischemia/reperfusion injury model was established. Compared with model rats that received saline, rats in the treatment group had smaller infarct volumes, lower brain water and malondialdehyde content, lower brain Ca(2+) levels, lower activities of serum lactate dehydrogenase and creatine kinase, and higher superoxide dismutase activity. In addition, the treatment group showed less damage to the brain tissue ultrastructure and better neurological function. Our findings indicate that Shenqi Fuzheng injection exerts neuroprotective effects in aged rats with cerebral ischemia/reperfusion injury, and that the underlying mechanism relies on oxygen free radical scavenging and inhibition of brain Ca(2+) accumulation.

Blood-brain barrier permeability change and regulation mechanism after subarachnoid hemorrhage.

We aimed to investigate the blood brain barrier (BBB) change caused by subarachnoid hemorrhage (SAH) and to explore the molecular mechanisms of acute brain injury after SAH. The SD rat model of SAH was firstly established by endovascular filament perforation technique. The changes of regional cerebral blood flow (rCBF), BBB permeability and ultrastructure of brain tissue at different time points after SAH were respectively observed by Doppler flowmetry, evans blue extravasation and transmission electron microscopy. Meanwhile, the expression changes of Claudin-5, Occludin, Zo-1 and Caveolin-1 were detected by immunohistochemistry and Western blot. Furthermore, the expressions of Akt, P-Akt and Foxo1A were also measured by Western blot. The change of BBB permeability showed two peaks at 3 and 72 h after SAH, corresponding to the change of rCBF. The BBB tight junction opening can be observed after SAH, and the largest opening was occurred at 3 h and 72 h. There was no significant change in Caveolin-1, Claudin-5 and Akt expressions after SAH (P > 0.05), while Zo-1 and Occludin were significantly down-regulated (P < 0.05). The expression of P-Akt was obviously reduced at 30 min and then increased at 1 and 24 h, while Foxo1A was up-regulated at 1 and 24 h after SAH (P < 0.05). Down-regulated Zo-1 and Occludin, as well as Akt/FOXO signaling pathway may be involved in the regulation of tight junction opening and the BBB permeability in the early stage after SAH.

The mechanism of the opening of the blood–brain barrier by borneol: A pharmacodynamics and pharmacokinetics combination study

Ethnopharmacological relevanceBorneol is widely used in traditional Chinese medicine to facilitate the distribution of central nervous system (CNS) drugs in brain due to its ability to open blood–brain barrier (BBB), however, the underlying mechanism is still unclear. In this study, the effect of borneol on different brain regions were investigated to explore the mechanism. Materials and methodsAfter oral administration of borneol (0.1, 0.2g/kg) for seven consecutive days, SD rats were injected with Rh123 (1.0mg/kg). The concentrations of Rh123 were detected in four brain regions of cortex, hippocampus, hypothalamus and striatum by a small animal vivo imaging system and a fluorescence microplate reader respectively. The ultrastructures of BBB were examined. Moreover, the expressions of the four transporters of ATP-binding cassette (ABC) family, multidrug resistance 1a (Mdr1a), multidrug resistance 1b (Mdr1b), multidrug resistance protein 1 (Mrp1), Mrp4, Mrp5 and breast cancer resistance protein (Bcrp) in the four brain regions were analyzed. Finally, the deliveries of borneol in the plasma and the four brain regions were examined by a pharmacokinetics study. ResultsAdministration of 0.2g/kg borneol produced loose structure in the tight junction and void structure between the endothelial cell and mesangial cell. Borneol at 0.1g/kg and 0.2g/kg increased the delivery of Rh123 in hippocampus and hypothalamus obviously. Permeability index followed a similar trend. Protein expression assays showed that borneol decreased the expression of Mdr1 and Mrp1 in hippocampus and hypothalamus. Further RT-PCR study showed that borneol decreased the expressions of both Mdr1a and Mdr1b in hippocampus and hypothalamus. The pharmacokinetics study demonstrated that the delivery of borneol in cortex was the most and that in striatum the least, with the deliveries of borneol in hippocampus and hypothalamus in between. ConclusionsBorneol showed tissue specific BBB-opening effect, which was associated with its regulation of the ultrastructure of brain tissues and the expressions of Mdr1a, Mdr1b and Mrp1. The present study indicated that borneol should be used in concert with drugs targeting hippocampus or hypothalamus to exert its synergistic effect to the maximum.

Effect of Shenfu on inflammatory cytokine release and brain edema after prolonged cardiac arrest in the swine

ObjectiveShenfu injection (SFI), a traditional Chinese formulation, has been confirmed to be protective against brain during ischemia and reperfusion injury. In this exploratory study, we investigated the action of SFI in regulating the inflammatory response and brain edema after cardiopulmonary resuscitation. MethodsAfter 8 minutes of untreated ventricular fibrillation (VF), pigs in the cardiopulmonary resuscitation group (n = 24) received a central venous injection of either SFI (SFI group; 1.0 mL/kg), epinephrine (EP group; 0.02 mg/kg), or saline (SA group). Levels of porcine-specific tumor necrosis factor α and interleukin in sera were measured using enzyme-linked immunosorbent assay at 0.5, 1, 2, 4, 6, and 24 hours after return of spontaneous circulation (ROSC). Surviving pigs were killed 24 hours after ROSC, and the brains were removed for electron microscopy, Western blotting, and quantitative real-time polymerase chain reaction analysis. ResultsCompared with the EP and SA groups, SFI decreased the levels of tumor necrosis factor α and interleukin-6 in serum and the brain (P < .05) and decreased the expression of nuclear factor κB and aquaporin-4 messenger RNA in the brain (P < .05). Shenfu injection also inhibited the expression of nuclear factor κB, matrix metalloproteinase 9, and aquaporin-4 protein after ROSC (P < .05). Observation of brain tissue ultrastructure showed that injury was alleviated in the SFI group compared with the SA and EP groups. ConclusionsOur exploratory experiments demonstrated that SFI reduced cerebral damage in a porcine model of VF, which may be related to suppression of the inflammatory reaction and decreased brain edema after ROSC.

Excitatory amino acid changes in the brains of rhesus monkeys following selective cerebral deep hypothermia and blood flow occlusion.

Selective cerebral deep hypothermia and blood flow occlusion can enhance brain tolerance to ischemia and hypoxia and reduce cardiopulmonary complications in monkeys. Excitotoxicity induced by the release of a large amount of excitatory amino acids after cerebral ischemia is the major mechanism underlying ischemic brain injury and nerve cell death. In the present study, we used selective cerebral deep hypothermia and blood flow occlusion to block the bilateral common carotid arteries and/or bilateral vertebral arteries in rhesus monkey, followed by reperfusion using Ringer’s solution at 4°C. Microdialysis and transmission electron microscope results showed that selective cerebral deep hypothermia and blood flow occlusion inhibited the release of glutamic acid into the extracellular fluid in the brain frontal lobe and relieved pathological injury in terms of the ultrastructure of brain tissues after severe cerebral ischemia. These findings indicate that cerebral deep hypothermia and blood flow occlusion can inhibit cytotoxic effects and attenuate ischemic/hypoxic brain injury through decreasing the release of excitatory amino acids, such as glutamic acid.

Effects of ethylbenzene on oxidative damage, ultrastructure and expressions of apoptosis-related genes in rat brain tissues

To investigate the influence of ethylbenzene on oxidative damage, ultrastructure and the expressions of apoptosis-related genes in the rat brain tissues. Four groups of 10 males of Sprague-Dawley rats were allocated randomly, and inhaled daily with different doses of ethylbenzene: 0, 433.5 mg/m³, 4335.0 mg/m³, and 6500.0 mg/m³ 6 h daily, 5 days per week for 13 weeks. The contents of glutathione (GSH) and malondialdehyde (MDA) and activity of acetylcholinesterase (AChE) were assayed, respectively. The ultrastructure of brain tissues was observed via electron microscope. The gene expression levels of Bax, Bcl-2, cytochrome C, caspase-9 and caspase-3 in brain tissues were measured by real-time polymerase chain reaction (PCR), respectively. The contents of MDA [(2.03 ± 0.56), (4.17 ± 1.31) nmol/mg pro] in the brain tissues of 4335.0 mg/m³ and 6500.0 mg/m³ ethylbenzene-treated groups were significantly higher than that [(1.08 ± 0.26) nmol/mg pro] in the control group (P < 0.05), while AChE activities [(0.321 ± 0.066), (0.276 ± 0.031), (0.202 ± 0.041) U/mg] and GSH contents [(35.19 ± 15.08), (33.42 ± 15.32), (27.99 ± 7.53) mg/g pro] in all ethylbenzene-treated groups were remarkably depressed (P < 0.05, P < 0.05, respectively). After 6500.0 mg/m³ ethylbenzene inhalation, the nucleolus exhibit demilune with decreased mitochondria. Electrondense of myelin occurred in the injured nerve, ascribing to lipid peroxidationed membrane. The gene expression level of Bax in brain tissue of 4335.0 mg/m³ and 6500.0 mg/m³ ethylbenzene-treated group was significantly higher than that in the control group (P < 0.05). Compared with the control group, the gene expression levels of cytochrome C, caspase-9 and caspase-3 in all ethylbenzene-treated groups were enhanced (P < 0.05, P < 0.05, respectively), while bcl-2 gene expression levels in all ethylbenzene-treated groups were decreased (P < 0.05). Ethylbenzene can induce oxidative damage and apoptosis in brain tissues. The apoptotic mechanism might be involved with up-regulation of Bax, cytochrome C, caspase-9 and caspase-3, as well as restraint of Bcl-2.

Tumour necrosis factor-α affects blood-brain barrier permeability and tight junction-associated occludin in acute liver failure

Cerebral oedema leading to cerebral herniation is a major cause of death during acute liver failure (ALF), but the underlying mechanism is not clear. We investigated the role of tumour necrosis factor (TNF)-alpha in changing the permeability of the blood-brain barrier (BBB) during ALF. ALF animal models were generated by administering D-galactosamine (GalN) and lipopolysaccharide, or GalN and TNF-alpha. ALF induction was blocked by first administering anti-TNF-alpha-IgG or anti-TNF-alpha-R1. We investigated the BBB permeability with Evans blue staining, and the structure with electron microscopy. BBB permeability increased in ALF mice and correlated with elevated serum TNF-alpha levels. No vascular endothelial cell (EC) apoptosis was detected, but electron microscopy of cells from human and mouse ALF tissues revealed tight junction (TJ) disruptions and EC shrinkage, as well as increased vesicles and vacuoles. In addition, the expression of the TJ-associated protein occludin was significantly decreased in both ALF mice and patients, although the expression of occludin mRNA did not change. Changes in BBB permeability, brain tissue ultrastructure and occludin expression in ALF-induced mice could be prevented by prophylaxis treatment with either antibody to TNF-alpha-IgG or antibody to TNF-alpha-R1. Our results suggest that TNF-alpha plays a critical role in the development of brain oedema in ALF, and that both vasogenic and cytotoxic mechanisms may be involved. Increased BBB permeability may be because of the disruption of TJs, and loss of the TJ-associated protein occludin.

Antithrombin iii and enoxaparin treatment inhibit contusion-triggered cell death, inflammation, hemorrhage and apoptosis after severe traumatic brain injury in rats

In this study, we aimed to show the neuroprotective effects of AT III and Enoxaparin after severe traumatic brain injury. The animals were divided into four groups as Group 1; control group, Group 2; trauma group, Group 3; AT III group and Group 4; Enoxaparin group. Severe trauma was performed by the weight dropping technique. These animals were killed 48 hours after injury. Histopathological and immunohistochemical analysis were performed. Specimens were graded for cell death, inflammation, hemorrhage and apoptosis. The control group showed normal ultrastructure of brain tissue. Trauma produced obvious damage. 8 rats (80%) in the trauma group demonstrated minimal inflammation and grade 5 cell death. Trauma increased hemorrhage and apoptosis scores to statistically significant levels (p < 0.001). Enoxaparin was found to reduce neuronal cell death but not as effectively as AT III. A statistically significant difference was observed between the AT III and Enoxaparin group according to inflammation grades. Significant antiapoptotic properties of AT III were observed while hemorrhage was more common in the Enoxaparin group. Anticoagulants such as AT III and enoxaparin are promising drugs in the treatment of traumatic brain injuries.

Electron microscopic studies of the brain edema after local brain injury in animals with changed immunological reactivity

It is well established at present that the course of pathological processes in local brain trauma depends on immunological reactivity of the organism and to a great extent on its sensitization to brain antigens.This study was undertaken to clarify the early ultrastructural changes of the nervous tissue in perifocal area of local brain wound in normal rabbits, those sensitized to brain antigens or desensitized by brain antigens after preliminary sensitization. In addition, the influence of sensitization and desensitization per se on brain tissue ultrastructure was studied. The animals were sensitized and desensitized with intravenous and intraperitoneal 20% water-salt extract of homologous brain tissue. The immunological state of the animals was checked by using the complement fixation test. The fixation of antibrain antibodies in perifocal area of the wound was studied by the direct Coons immunofluorescence method.