Evans Blue Dye Content Research Articles

Effects of Gryllus bimaculatus and Oxya chinensis sinuosa extracts on brain damage via blood-brain barrier control and apoptosis in mice with pentylenetetrazol-induced epilepsy.

The demand for environmentally friendly foods with high nutritional value and low carbon emissions is increasing with the aging of the global population and the crisis of food resources. Edible insects are becoming increasingly well-known as such foods. This study evaluated the effects and mechanisms of Gryllus bimaculatus (Cricket) (Gb) and Oxya chinensis sinuosa (Grasshopper) (Ocs) extracts on epilepsy. A pentylenetetrazol (PTZ)-induced seizure mouse model was used for the study, and Gb and Ocs extracts were administered for 29 days on alternate days at concentrations of 8 g/kg and 16 g/kg. The integrity of the blood-brain barrier (BBB) and brain edema was measured using the perfusion of Evans blue dye and brain water content. Gb and Ocs extracts prevented BBB permeabilization and cerebral edema through increasing the expression of tight junction-associated proteins in the endothelial cells and reducing water content in PTZ-treated mice. Additionally, Gb and Ocs extracts protected neurons from oxidative stress and apoptosis in different brain areas. These protective effects were demonstrated through the restoration of the expression of neuronal nuclear protein and postsynaptic density protein-95, thus increasing the levels of glutathione and superoxide dismutase, decreasing lipid peroxidation, and recovering apoptosis-associated proteins, such as Bax, cleaved PARP, and cleaved caspase-3, in epileptic mice. In addition, Gb and Ocs extracts rescued PTZ-induced hyperexcitable neurons to control mice level, as supported by the restored expression of gamma-aminobutyric acid (GABA) transporter 1, the metabotropic glutamate receptors-GRM2/3, and BDNF. This study suggested that Gb and Ocs extracts are novel medicinal candidates that can help ameliorate epilepsy by improving BBB health and preventing oxidative stress-mediated apoptosis.

Neuregulin-1 reduces vascular leak and airway epithelium permeability caused by respiratory viral infection

Abstract Respiratory viruses, such as Respiratory Syncytial Virus (RSV), are associated with significant morbidity and mortality. Mice with pre-existing atopy are protected from mortality to Sendai virus (SeV), a rodent virus related to RSV. We found that lungs of atopic mice had increased levels of neuregulin-1(NRG1), and hypothesized that SeV induces death via lung vascular leak, and that NRG1 might inhibit vascular leakage. Non-atopic C57Bl/6 mice were treated with NRG1 (500ng/30 mcl, i.n) or PBS for five days before infection with SeV (2×10 5pfu) or UV-inactivated SeV (UV-SeV) and 8 days post viral inoculation, Evan’s Blue Dye (EBD) was injected i.v with EBD concentration determined spectrophotometrically one hour later in homogenized lungs. Vascular leak in SeV-infected mice was 65.25% and 46.62% more than in UV-SeV-treated or SeV-infected mice pre-treated with NRG1, respectively. We also found that RSV infection of well-differentiated human bronchial epithelial cells (hBEC) grown at the air-liquid interface caused 70KDa FITC-Dextran leakage 8 days post-inoculation. NRG1 pretreatment for 5 days before RSV inoculation reduced epithelial leakage 8 days post-inoculation by 2.5 fold (p<0.001). These results suggest NRG1 has the potential to improve epithelial barrier function in rodent and human systems and may explain the increased survival following a severe respiratory viral infection. Abigail Wexner Research Institute at Nationwide Children’s Hospital, Start-up fund to MHG

Effects of Rourea coccinea ethanolic root extract on ovalbumin-induced allergic asthma in rats

Rourea coccinea (syn. Byrsocarpus coccineus) Schum. and Thonn. (Connaraceae) is a medicinal plant that is being used for the treatment of various disorders in Tropical Africa. Previously, we reported anti-inflammatory and antioxidant effects of ethanolic extract of R. coccinea root bark (EERc). The present study aimed to test protective potential effects of EERc treatments against ovalbumin-induced airway lung inflammatory and to investigate some of its possible underlying mechanism on allergic asthma. Rats were sensitized and challenged with ovalbumin (OVA), and were orally treated daily with EERc at 200, 400 and 800 mg/kg from day 24 to day 27 post sensitization. The number of total and differential inflammatory cells, leakage of Evans blue dye tracer, histamine and TNF-α level in bronchoalveolar lavage (BAL) fluid were measured. OVA instillation induced airway lung inflammation, which was significantly suppressed by pre-treatment with EERc. Analysis of bronchoalveolar lavage (BAL) revealed that EERc pre-treatment significantly inhibited leukocytosis and reduced Evans blue dye content in the BAL fluid. EERc also significantly decreased the production and release of histamine and TNF-α. Our study shows that EERc possesses significant anti-allergic activity which might be attributed to reduction of histamine, TNF-α in the BAL fluid.

Therapeutic Effect of <i>Aloe vera</i> on Croton Oil Induced Hemorrhoids

Hemorrhoids are vascular structures in the anal canal with swollen veins in the lowest part of the rectum/anus. Till date, there is no specific treatment available for different grades of hemorrhoids. However, it is evident that lesser invasive options are to have opted for at the earliest along with conservative measures such as analgesics and anti-inflammatory agents. The study evaluates the efficacy of gel obtained from Aloe barbadensis Miller in treating hemorrhoids in a croton oil-induced Wistar rat model. Animals were allocated into 5 groups. Group I and II served as the normal and negative control, Group III as standard, and Group IV and V received an oral route and a topical route respectively. Biochemical parameters such as TNF-? and IL-6 were estimated in each group after the therapy of 5 days. Quantitative estimation of edema was done by determining the Evans blue dye concentration in the plasma exudates in recto-anal tissue. The recto-anal coefficient was estimated as a direct measure of inflammation. Histopathological variations among the groups were analyzed. Statistical analysis of the data affirms the curative effect of aloe vera on Hemorrhoids. Results demonstrate that aloe gel is much more effective when compared to Pilex ointment which was used as standard (p<0.05). However, oral preparation was not found to be effective in mitigating the disease as that standard (p>0.05).

Normothermic ex vivo lung perfusion outperforms conventional cold preservation in a deceased rat lung

BackgroundUtilization rate of donor lungs in China is constrained by the inefficiency of conventional cold preservation (COLD) in lung transplantation. We assessed the performance of normothermic ex vivo lung perfusion (EVLP) in lung donors following cardiac death (DCD) with fresh EVLP perfusate.MethodsA total of 24 adult Sprague-Dawley (SD) rats were randomized into three groups (EVLP, COLD, and control groups) with 8 rats each. Fresh EVLP perfusate was prepared for lung perfusion. The pH, electrolyte concentration, perfusate penetration pressure during irrigation, physiological function, integrity of barrier function, pathological changes, and expressions of inflammation-related cytokines of donor lungs were examined.ResultsThe pH, electrolyte concentration, osmotic pressure of the perfusate were kept stable for 4 hours after EVLP was administered. Pulmonary arterial pressure (PAP), pulmonary venous pressure (PVP), pulmonary venous oxygenation index (PaO2/FiO2), and end carbon dioxide partial pressure (PCO2) in the EVLP group were all within acceptable limits. After 4 hours, the oxygenation index was significantly higher in the EVLP group compared with that of the COLD group (P=0.0032). The EVLP group had a decreased wet/dry weight ratio (P=0.0155) and Evans blue dye content (P=0.0075) compared to that of the COLD group. Pathological examination showed more obvious lung damage in the COLD group than in the EVLP group. However, there was no difference in protein expression of high mobility group box 1 (HMGB1) and toll-like receptor 4 (TLR4) between the EVLP group and the COLD group.ConclusionsFresh lung perfusate could be used for EVLP to protect and repair donor lungs. Normothermic EVLP performed better than conventional cold preservation. EVLP might be powerful for lung quality maintenance and may have potential for anti-inflammation.

The Effect of Venom of Egyptian Spitting Cobra Naja nubiae on Vascular Permeability of Hepatic and Renal Tissues

Background: Among venomous elapid snakes, cobras have the highest public awareness, as their venom represents a combination of proteins, peptides, and enzymes that have a range of biochemical and pharmacological roles and are also the main constitutes of biological activity and lethal toxicity. Objectives: The study aimed to evaluate the effect of the venom of Egyptian Spitting Cobra, Naja nubiae, on the vascular permeability based on the extravasation of the azo dye Evans blue (EB) into the tissues of the liver and kidneys of animals envenomed with low (¼ LD50; 0.32 mg/kg) and high (½ LD50; 0.65 mg/ kg) doses at three sampling times (30, 120, 360 min) post-injection of the venom. Methods: Fifty-four adult male Albino rats (8 weeks old and 180±2 0 g body weight) were divided into three main groups (n=6). In the control group, rats were subcutaneously (SC) injected with saline solution. Envenomed groups were SC injected, one group with 0.32 mg/kg and the other group with 0.65 mg/kg body weight of crude venom, respectively. Rats were I.V injected with EB dye 20 minutes before SC injection with saline solution as control animals and with Naja nubiae venom as treatment groups. Results: The results illustrated a high significant rate of EB extravasation to hepatic and renal tissues by the colorimetric determination of EB dye concentration. Conclusion: The venom of Naja nubiae can cause increased hepatic and renal vascular permeability which may explain the inflammatory effect induced by this venom.

Pulsed high magnetic field-induced reversible blood-brain barrier permeability to enhance brain-targeted drug delivery

ABSTRACT The present study aimed to select an effective Pulsed High Magnetic Field (PHMF) stimulation protocol that would induce the Blood-Brain Barrier’s (BBB) reversible permeability to enhance brain-targeted drug delivery. PHMF was applied to the skull over the right hemisphere of 60 Wistar rats. The sham group contained other 10 rats that did not receive PHMF stimulation. The investigated parameters were repetition frequencies (0.25, 1, and 4 Hz as well as the effective low frequency combined with 10 Hz) and numbers of pulses in each train. Evans Blue Dye (EBD) uptake within the brain parenchyma was measured to select an effective PHMF stimulation protocol. BBB reversibility was evaluated by measuring EBD uptake and Gadobutrol retention, through MRI signal intensity enhancement, within brain parenchyma after exposure to the effective PHMF stimulation protocol at different time points including 0.5, 1, and 24 hours. The obtained results showed that the PHMF stimulation increased the BBB’s reversible permeability; this increase was more significant for 28 pulses with 1 Hz frequency (P < .0001). Changes in EBD uptake and MRI signal intensity in the exposed side (right hemisphere) peaked within 0.5–1 hour and returned to normal levels 24 hours after exposure to the effective protocol of PHMF stimulation (28 pulses with 1 Hz frequency). The Contrast-Enhanced MRI (CE-MRI) signal intensity confirmed the changes in EBD concentration. PHMF stimulation can be used as an effective protocol for enhancing the permeability reversibly of BBB, hence considered a potential clinical approach to brain-targeted drug delivery.

Protection Against Blood-Brain Barrier Permeability as a Possible Mechanism for Protective Effects of Thymoquinone Against Sickness Behaviors Induced by Lipopolysaccharide in Rats

Background: Blood-brain barrier (BBB), as well-known protection for the brain, plays an active role in normal homeostasis. It might be changed by a range of inflammatory mediators to have a role in sickness behaviors. Objectives: Regarding the anti-inflammatory effects of thymoquinone (TQ), its protection against BBB permeability, as a possible mechanism for protective effects against sickness behaviors elicited by lipopolysaccharide (LPS), was evaluated in rats. Methods: The animals were grouped as follows and treated (n = 10 in each): (1) control (saline); (2) LPS 1 mg/kg, was injected two hours before behavioral tests for two weeks; (3-5) 2, 5, and 10 mg/kg TQ, respectively was injected 30 min before LPS injection. Open-field (OF), elevated plus-maze (EPM) and Forced Swimming test (FST) were done. Finally, the animals were anesthetized to evaluate for BBB permeability using Evans blue (EB) dye method. Results: Compared with control, LPS decreased the peripheral distance and crossing and also total crossing and distance in OF, (P &lt; 0.01 - P &lt; 0.001). The central crossing and distance and central time in all three treatment groups were more than LPS (P &lt; 0.05 - P &lt; 0.001). LPS also reduced the entries and the time spent in the open arm while increased the time spent in the closed arm in EPM (P &lt; 0.05 - P &lt; 0.001). The effects of LPS were reversed by TQ (P &lt; 0.05 - P &lt; 0.001). In FST, the immobility time and active time were increased and decreased by LPS compared with control (P &lt; 0.001), respectively. In all three TQ-treated groups, the active and climbing times were more while the immobility time was fewer than the LPS (P &lt; 0.05 - P &lt; 0.001). The animals of the LPS group showed more EB dye content in their brain tissue than the control group (P &lt; 0.05 - P &lt; 0.001). TQ significantly reduced EB dye content of the brain tissues (P &lt; 0.05 - P &lt; 0.001). Conclusions: According to this study, protection against BBB permeability as a possible mechanism for the protective effects of TQ against sickness behaviors induced by LPS might be suggested.

Gut-lymph-lung pathway mediates sepsis-induced acute lung injury.

This review attempts to unveil the possible mechanisms underlying how gut lymph affects lung and further gives rise to acute respiratory distress syndrome, as well as potential interventional targets under the condition of ischemia-reperfusion injury. We searched electronic databases including PubMed, MEDLINE, Cochrane Central Register of Controlled Trials, Google Scholar, Web of Science, and Embase to identify relevant literatures published up to December 2019. We enrolled the literatures including the Mesh Terms of “gut lymph or intestinal lymph and acute lung injury or acute respiratory distress syndrome.” Gut is considered to be the origin of systemic inflammation and the engine of multiple organ distress syndrome in the field of critical care medicine, whereas gut lymph plays a pivotal role in initiation of ischemia-reperfusion injury-induced acute respiratory distress syndrome. In fact, in the having been established pathologic model of sepsis leading to multiple organ dysfunction named by Gut Lymph theory, a variety of literatures showed the position and role of changes in gut lymph components in the initiation of systemic inflammatory response, which allows us to screen out potential intervention targets to pave the way for future clinic and basic research.

Sustained laryngeal transient receptor potential vanilloid 1 activation inhibits mechanically induced swallowing in anesthetized rats.

A major component of gastric acid is hydrochloric acid (HCl), which can activate transient receptor potential vanilloid 1 (TRPV1). In the present study, we investigated how sustained laryngeal TRPV1 activation affects the frequency of the swallowing reflex. Experiments were carried out on 85 male Sprague-Dawley rats. The effects of short and sustained application of chemicals (3 µl of 0.1 N HCl or capsaicin) on the frequency of swallowing and on time-dependent changes in the occurrence of swallowing evoked by supralaryngeal nerve stimulation were determined. To evaluate vascular permeability of the larynx, Evans blue dye was intravenously injected after 5 or 60 min of sustained TRPV1 activation. SB366791 (a TRPV1 inhibitor) and Cap/QX-314 (a TRPV1-expressed neuronal inhibitor) significantly inhibited HCl/capsaicin-induced swallowing, but air flow-induced swallowing was not affected. Although the number of air flow-induced swallows followed by capsaicin stimulation was not affected within 5 min, it was significantly reduced by 60-min capsaicin or HCl application. The swallowing threshold associated with supralaryngeal nerve stimulation did not significantly change throughout the recording period. Evans blue dye concentrations in the larynx were significantly higher at 60 min in the 10-5 M capsaicin group than in the control group. Our results suggest that sustained TPRV1 activation not only desensitizes TRPV1 but also inactivates mechanoreceptors, which may be attributed to increases in vascular permeability and edema, as part of an inflammatory process.NEW & NOTEWORTHY Although a transient receptor potential vanilloid 1 (TRPV1) inhibitor or TRPV1-expressed neuronal inhibitor significantly inhibited HCl/capsaicin-evoked swallowing, air flow-induced swallowing was not affected. The number of air flow-induced swallows was significantly reduced within 60 min of TRPV1 activation. Evans blue dye concentration in the larynx increased 60 min after capsaicin application. TPRV1 activation not only desensitizes TRPV1 but also inactivates mechanoreceptors caused by increases in vascular permeability and edema.

Haem oxygenase protects against thrombocytopaenia and malaria-associated lung injury

BackgroundMalaria-triggered lung injury can occur in both severe and non-severe cases. Platelets may interact with parasitized erythrocytes, leukocytes and endothelium. These interactions can lead to microvessel obstructions and induce release of inflammatory mediators. Induction of the haem oxygenase enzyme is important in the host’s response to free haem and to several other molecules generated by infectious or non-infectious diseases. In addition, an important role for the haem oxygenase-1 isotype has been demonstrated in experimental cerebral malaria and in clinical cases. Therefore, the present work aims to determine the influence of haem oxygenase in thrombocytopaenia and acute pulmonary injury during infection with Plasmodium berghei strain NK65.MethodsC57BL/6 mice were infected with P. berghei and analysed 7-10 days post-infection. For each experiment, Cobalt Protoporphyrin IX/CoPPIX or saline were administered. Bronchoalveolar lavage fluid was used for total and differential leukocyte count and for protein measurement. Lungs were used for histological analyses or for analysis of cytokines and western blotting. The lung permeability was analysed by Evans blue dye concentration. Platelet-leukocyte aggregate formation was assayed using the flow cytometer.ResultsPlasmodium berghei NK65 infection generated an intense lung injury, with increased levels of inflammatory mediators, oedema, and cell migration into the lung. Plasmodium berghei infection was also accompanied by marked thrombocytopaenia and formation of platelet-leukocyte aggregates in peripheral blood. Treatment with the HO-1 inducer cobalt protoporphyrin IX (CoPPIX) modified the inflammatory response but did not affect the evolution of parasitaemia. Animals treated with CoPPIX showed an improvement in lung injury, with decreased inflammatory infiltrate in the lung parenchyma, oedema and reduced thrombocytopaenia.ConclusionData here presented suggest that treatment with CoPPIX inducer leads to less severe pulmonary lung injury and thrombocytopaenia during malaria infection, thus increasing animal survival.

Blood-Brain Barrier Disruption as a Potential Target for Therapy in Posterior Reversible Encephalopathy Syndrome: Evidence From Multimodal MRI in Rats.

Background: To explore blood–brain barrier disruption in hypertensive posterior reversible encephalopathy syndrome.Methods: The hypertension rat models were successfully established and scanned on 7T micro-MRI. MRI parameter maps including apparent diffusion coefficient, T1 value, and perfusion metrics such as cerebral blood volume, cerebral blood flow, mean transit time and time to peak maps, were calculated.Results: The ADC values of the experimental group were higher than those of the control group both in cortical (P < 0.01) and subcortical (P < 0.05) regions. Voxel-wise analysis of ADC maps localized vasogenic edema primarily to the posterior portion of the brain. The increase in cerebral blood volume and cerebral blood flow values were found in the cortical and subcortical regions of rats with acute hypertension. No correlation was found between perfusion metrics and mean arterial pressure. The Evans blue dye content was higher in the posterior brain region than the anterior one (P < 0.05).Conclusions: Cerebral vasogenic edema resulting from acute hypertension supports the hypothesis of posterior reversible encephalopathy syndrome as the result of blood–brain barrier disruption, which maybe the potential therapeutic target for intervention.

Using computerized tomography perfusion to measure cerebral hemodynamics following treatment of traumatic brain injury in rabbits.

The present study aimed to investigate the use of computerized tomography (CT) perfusion for evaluating cerebral hemodynamics following traumatic brain injury (TBI) in rabbits. The animals were randomly assigned into four groups (n=10 animals/group): i) Control, ii) TBI, iii) TBI + common decompression and iv) TBI + controlled decompression groups. A TBI model was established in rabbits using epidural balloon inflation. In the groups receiving intervention, animals were provided common decompression or controlled decompression treatments. Conventional CT and CT perfusion scanning were performed, with cerebral hemodynamic indices, including regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV) and mean transit time (MTT) being measured. Blood-brain barrier (BBB) permeability was evaluated using Evans blue staining. Compared with those in the control group, rCBF and rCBV values of the bilateral temporal lobes and basal ganglion in the TBI, TBI + common decompression and TBI + controlled decompression groups were significantly lower, whereas the MTT values were markedly prolonged and Evans blue dye content was greatly increased (P<0.01). Controlled decompression was demonstrated to be more potent than common decompression for preventing TBI-induced decline in rCBF and rCBV values in the bilateral temporal lobes and basal ganglion, as well as reversing TBI-induced extension of MTT in the bilateral temporal lobes (P<0.01 vs. TBI group). However, neither common nor controlled decompression could reduce TBI-induced increase in BBB permeability. In conclusion, these findings indicate that CT perfusion may be used to monitor cerebral hemodynamics following TBI in rabbits. Controlled decompression was deduced to be more potent than common decompression for preventing abnormalities in cerebral hemodynamics after TBI.

Effects of methyl-beta-cyclodextrin on blood-brain barrier permeability in angiotensin II-induced hypertensive rats

The blood-brain barrier (BBB) permeability primarily increases in cerebral venules during acute hypertension. Methyl-β-cyclodextrin (MβCD), a cholesterol-depleting agent, decreases the expression of caveolins disrupting caveolar structures. We aimed to determine the effects of MβCD on the BBB permeability of angiotensin (ANG) II-induced hypertensive rats. Three minutes after MβCD administration (5 mg/kg), acute hypertension was induced by ANG II (60 µg/kg). Evans blue (EB) and horseradish peroxidase (HRP) tracers were used to assess BBB permeability. Immunohistochemistry for caveolin (Cav)-1 and tight junction protein claudin-5 was performed. EB dye content significantly increased in both cerebral cortices and left hippocampus in MβCD (P < 0.05), right cerebral cortex and both hippocampi in ANG II (P < 0.05; P < 0.01), and both cerebral cortices and hippocampi in MβCD plus ANG II groups compared with controls (P < 0.05; P < 0.01). A significant decrease in claudin-5 immunostaining intensity was observed in animals treated with MβCD compared with controls (P < 0.05). Cav-1 immunostaining intensity increased in ANG II group (P < 0.05). Ultrastructurally, HRP reaction products were observed in endothelial cells of the microvessels in the hippocampus region in MβCD group while the tracer was mainly localized in astrocytes and neurons in ANG II, and MβCD plus ANG II groups. The endothelial cells of the venules in the cerebral cortex of the animals in the latter experimental groups also showed an abundance of caveolar vesicles devoid of HRP reaction products. Our results revealed that MβCD did not provide overall protective effects on BBB integrity in acute hypertension and even led to BBB disruption in normotensive animals.

Knockdown of TFPI-Anchored Endothelial Cells Exacerbates Lipopolysaccharide-Induced Acute Lung Injury Via NF-κB Signaling Pathway.

ABSTRACTAs activation of the coagulation system is both a consequence and contributor to acute lung injury (ALI), pulmonary coagulopathy has become a potential target for therapeutic intervention in ALI patients. We investigated the effects and possible mechanisms of endothelial cell (EC)-anchored tissue factor pathway inhibitor (TFPI) on lipopolysaccharide (LPS)-induced ALI in mice. To assess the effect of EC-anchored TFPI deletion on ALI indices, TFPI knockout (cKO) mice were generated. Mice were instilled by direct intratracheal injection LPS for the preparation of an ALI model. Evans blue dye (EBD) was injected intravenously 2 h prior to animal sacrifice (48 h post-LPS). Lungs were fixed for histopathology and the prepared tissue was homogenized or used to extract bronchoalveolar lavage fluid (BALF) or detect EBD concentration. TFPI knockdown mice with ALI were compared to wild-type (WT) mice with ALI to assess the effect of TFPI on endothelial barrier function and inflammation. TFPI deletion markedly exacerbated LPS histopathological changes in lung, and the LPS changes in protein, EBD extravasation, proinflammatory cytokines TNF-α, IL-1β, and IL-6 in BALF in lung. The number and infiltration of white blood cells (WBCs) from BALF and lung tissue of TFPI cKO mice with LPS-challenged ALI was increased compared to WT mice with LPS-challenged ALI. We also found further increased toll-like receptor 4 and nuclear factor kappa-light-chain-enhancer of activated B cells activation and additional expression of vascular cell adhesion molecule 1 and reduction of angiotensin converting enzyme 2 expression in TFPI cKO+LPS mice compared with WT+LPS mice. Endothelial-specific TFPI deficiency promoted LPS-induced pulmonary inflammation and endothelial barrier permeability possibly via toll-like receptor 4-mediated nuclear factor kappa-light-chain-enhancer of activated B cells signaling pathway activation.

In vivo monitoring blood-brain barrier permeability using spectral imaging through optical clearing skull window.

The blood-brain barrier (BBB) plays a key role in the health of the central nervous system. Opening the BBB is very important for drug delivery to brain tissues to enhance the therapeutic effect on brain diseases. It is necessary to in vivo monitor the BBB permeability for assessing drug release with high resolution; however, an effective method is lacking. In this work, we developed a new method that combined spectral imaging with an optical clearing skull window to in vivo dynamically monitor BBB opening caused by 5-aminolevulinic acid (5-ALA)-mediated photodynamic therapy (PDT), in which the Evans blue dye (EBd) acted as an indicator of the BBB permeability. Using this method, we effectively monitored the cerebrovascular EBd leakage process. Moreover, the analysis of changes in the vascular and extravascular EBd concentrations demonstrated that the PDT-induced BBB opening exhibited spatiotemporal differences in the cortex. This spectral imaging method based on the optical clearing skull window provides a low-cost and simply operated tool for in vivo monitoring BBB opening process. This has a high potential for the visualization of drug delivery to the central nervous system. Thus, it is of tremendous significance in brain disease therapy. Monitoring the changes in PDT-induced BBB permeability by evaluating the EBd concentration using an optical clearing skull window. (A) Entire brains and coronal sections following treatment of PDT with/without an optical clearing skull window after injection of EBd. (B) Typical EBd distribution maps before and after laser irradiation captured by the spectral imaging method. (Colorbar represents the EBd concentration).

Changes in the Permeability and Expression of Markers of the Structural and Functional Integrity of the Blood–Brain Barrier under Early Postnatal Hypoxia in vivo

Pathologies associated with perinatal exposure of the CNS to damaging factors, including hypoxia, are a serious problem. However, the mechanisms by which they influence the development of brain damage have been insufficiently studied. The purpose of this study is to analyze the BBB permeability and expression of markers of its structural and functional integrity in animals with hypoxia (rats subjected to hypoxia at the age of P7) at the early (1 hour after the hypoxia) and delayed (P28) periods of their development. In sections of the rat brains, we immunohistochemically evaluated the expression of HIF-1 and Rac1; the Evans blue dye content was measured by the photometric method in the brain homogenates. In animals subjected to hypoxia, BBB permeability increased, CD31 expression was reduced, RAC1 expression increased, HIF-1-positive cells were retained in the hippocampus mainly at the early stage of development; CD31 and RAC1 expression was suppressed during the delayed period of development. The most-pronounced brain damage at the age of P7 corresponds to changes in the structural and functional integrity and permeability of the BBB; the recovery of a neurological deficit and the permeability of the BBB (at the age of P28) under damage to the brain corresponds to the period of reparative angiogenesis, as well as manifestations of HIF-1 effects in endothelial cells and astrocytes in the cortex and limbic system.

Curcumin ameliorated ventilator-induced lung injury in rats

BackgroundCurcumin (CUR) is a Chinese medicine monomer with antioxidant and anti-inflammatory properties. The aim of this study was to investigate the effects and mechanisms of CUR treatment on ventilator-induced lung injury (VILI) in rats. MethodsTotal 50 SD rats were divided into five groups: sham, VILI, VILI+CUR-50 (CUR 50 mg/kg pretreated intraperitoneal), VILI+CUR-200 (CUR 200 mg/kg pretreated intraperitoneal) and VILI + DXM (5 mg/kg pretreated intraperitoneal). The morphology and ultrastructure were observed by microscope and transmission electron microscope. The wet to dry ratio, protein concentration in bronchoalveolar lavage fluid (BALF), evans blue dye (EBD) content, nuclear factor kappa B (NF-κB) activity, myeloperoxidase (MPO), malondialdehyde (MDA), xanthine oxidase (XO) and total antioxidative capacity (TAOC) levels were measured. ResultsHistological studies revealed that inflammatory cells infiltration and alveolar edema were significantly severe in VILI as compared to other groups. CUR-200 and DXM treatment reversed lung injury significantly. The wet to dry ratio, protein concentration in BALF, EBD content, MPO activity, tumor necrosis factor (TNF)-α level and NF-κB activity were significantly increased in VILI group as compared to other groups. CUR-200 and DXM treatment significantly suppressed permeability and inflammation induced by ventilation. Furthermore, the significantly higher MDA content in VILI could be markedly decreased by CUR-200 and DXM treatment while the levels of XO and TAOC were markedly recovered only by CUR (200 mg/kg) treatment after VILI. ConclusionCUR could inhibit the inflammatory response and oxidative stress during VILI, which is partly through NF-κB pathway.

The Effects of Estrogen Receptors' Antagonist on Brain Edema, Intracranial Pressure and Neurological Outcomes after Traumatic Brain Injury in Rat.

Background:In previous studies, the neuroprotective effect of 17β-estradiol in diffuse traumatic brain injury has been shown. This study used ICI 182,780, a non-selective estrogen receptor antagonist, to test the hypothesis that the neuroprotective effect of 17β-estradiol in traumatic brain injury is mediated by the estrogen receptors. Methods: The ovariectomized rats were divided into eight groups. Brain injury was induced by Marmarou’s method. Estrogen was injected 30 minutes after traumatic brain injury, and ICI 182,780 was injected before traumatic brain injury and also before estrogen treatment. In one group only ICI 182,780 was injected. The brain water content and Evans blue dye content were measured 24 and 5 hours after traumatic brain injury, respectively. The neurologic outcomes and intracranial pressure were assessed before, 4, and 24 hours after traumatic brain injury. Results: Brain water content and Evans blue content were less in estrogen-treated group comparison to vehicle group. ICI 182,780 eliminated the effects of estrogen on brain edema and brain blood barrier permeability. Intracranial pressure was increased significantly after trauma, and estrogen decreased intracranial pressure at 4 and 24 hours after traumatic brain injury in comparison to vehicle. This inhibitory effect was also eliminated by treatment with ICI182,780. ICI 182,780 also inhibited the estrogen induced increase in neurologic outcomes following traumatic brain injury. However, the use of ICI 182,780 alone had no neuroprotective effect after traumatic brain injury. Conclusion: The results suggest that classical estrogen receptors have probably a role in the neuroprotective function of estrogen following traumatic brain injury.

Optimization of Evans blue quantitation in limited rat tissue samples.

Evans blue dye (EBD) is an inert tracer that measures plasma volume in human subjects and vascular permeability in animal models. Quantitation of EBD can be difficult when dye concentration in the sample is limited, such as when extravasated dye is measured in the blood-brain barrier (BBB) intact brain. The procedure described here used a very small volume (30 µl) per sample replicate, which enabled high-throughput measurements of the EBD concentration based on a standard 96-well plate reader. First, ethanol ensured a consistent optic path length in each well and substantially enhanced the sensitivity of EBD fluorescence spectroscopy. Second, trichloroacetic acid (TCA) removed false-positive EBD measurements as a result of biological solutes and partially extracted EBD into the supernatant. Moreover, a 1:2 volume ratio of 50% TCA ([TCA final] = 33.3%) optimally extracted EBD from the rat plasma protein-EBD complex in vitro and in vivo, and 1:2 and 1:3 weight-volume ratios of 50% TCA optimally extracted extravasated EBD from the rat brain and liver, respectively, in vivo. This procedure is particularly useful in the detection of EBD extravasation into the BBB-intact brain, but it can also be applied to detect dye extravasation into tissues where vascular permeability is less limiting.