Effects of selective hypothermia on blood-brain barrier integrity and tight junction protein expression levels after intracerebral hemorrhage in rats

2013 ◽  
Vol 394 (10) ◽  
pp. 1317-1324 ◽  
Author(s):  
Hongwei Sun ◽  
Ying Tang ◽  
Xiqin Guan ◽  
Lanfeng Li ◽  
Desheng Wang

Abstract Hypothermia has neuroprotective effects on global cerebral ischemic injuries. However, its efficacy after intracerebral hemorrhage (ICH) is inconclusive. In this study, bacterial collagenase was used to induce ICH stroke in male Wistar rats. We assessed the effects of normothermia and 4 h of local hypothermia (∼33.2°C) initiated 1, 6, or 12 h after collagenase infusion on hemorrhage volume and neurological outcomes. Following early cooling initiated after 1 h, blood-brain barrier (BBB) disruption and brain water content were tested. Furthermore, the expression levels of tight junction (TJ) proteins (claudin 5 and occludin) and the proinflammatory cytokines interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) were determined using Western blotting, real-time quantitative PCR, and immunohistochemical staining at 1 and 3 d after ICH. Early local hypothermia tends to reduce hemorrhagic volume and neurological deficits, but the difference is not statistically significant compared with other groups. However, early hypothermia significantly reduces BBB disruption, edema formation, the expression levels of IL-1β and TNF-α, and the loss of TJ proteins. Together, these data suggest that local hypothermia is an effective treatment for edema formation and BBB disruption via the upregulation of TJ proteins and the suppression of TNF-α and IL-1β.

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Wei Ling Lau ◽  
Mary Tarbiat-Boldaji ◽  
Hayley Smalls ◽  
Ane Nunes ◽  
Javad Savoj ◽  
...  

Introduction: Cerebral microbleeds are more common in chronic kidney disease (CKD) and dialysis patients compared to the general population. Diminished kidney function alone appears to be a risk factor for microbleeds, independent of age and hypertension. Microbleed burden in CKD patients is associated with increased risk of future hemorrhagic stroke and with cognitive dysfunction. The mechanisms that drive uremic microbleed formation are unclear. Hypothesis: We hypothesized that CKD mice are predisposed to develop cerebral microhemorrhages (the pathologic substrate of microbleeds), and that a standardized inflammatory stimulus (lipopolysaccharide, LPS) will amplify microhemorrhage burden in CKD mice compared to non-CKD controls (CTL). We also hypothesized that uremia induces depletion of tight junction proteins, altering blood-brain barrier integrity and representing a potential mechanism of microbleed formation. Methods: Animal groups included CTL (n=3), CKD (n=3), CTL+LPS (n=5) and CKD+LPS (n=5). CKD induction in male C57BL/6 mice was achieved via nephrotoxic adenine diet x18 days. Two weeks following CKD induction, CKD and control mice were treated with LPS 1 mg/kg i.p. dosed at 0, 6 and 24 hours. Brains were harvested one week after LPS injections and 40-micron sections were stained using Prussian blue to identify microhemorrhages. Immunohistochemistry was performed for the blood-brain barrier tight junction protein claudin-5. Results: CKD mice had significantly elevated blood urea nitrogen, and tubulointerstitial fibrosis was present on kidney histology. Total number of microhemorrhages per brain was 2.3±1.5 (mean ± standard error of the mean) for CTL mice, 8.3±1.5 for CKD mice, 23.2±4.2 for CTL+LPS mice, and 27.6±6.2 for CKD+LPS mice (p<0.05 for CKD+LPS vs. CTL). Immunostaining showed decreased claudin-5 expression in CKD mice compared to CTL. Conclusions: We have generated a mouse model that will facilitate future mechanistic studies in the field of uremic microbleeds. Our initial findings suggest that CKD alters blood-brain barrier integrity and that inflammation amplifies development of microbleeds in CKD.


2021 ◽  
Author(s):  
Kei Sato ◽  
Shinsuke Nakagawa ◽  
Yoichi Morofuji ◽  
Yuki Matsunaga ◽  
Takashi Fujimoto ◽  
...  

Abstract Background Cerebral infarction accounts for 85% of all stroke cases. Even in an era of rapid and effective recanalization using an intravascular approach, the majority of patients have poor functional outcomes. Thus, there is an urgent need for the development of therapeutic agents to treat acute ischemic stroke. We evaluated the effect of fasudil, a Rho kinase inhibitor, on blood brain barrier (BBB) functions under normoxia or oxygen-glucose deprivation (OGD) conditions using a primary cell-based in vitro BBB model. Medhods: BBB models from rat primary cultures (brain capillary endothelial cells, astrocytes, and pericytes) were subjected to either normoxia or 6-hour OGD/24-hour reoxygenation. To assess the effects of fasudil on BBB functions, we evaluated real time impedance, transendothelial electrical resistance (TEER), sodium fluorescein permeability, and tight junction protein expression using immunohistochemistry and western blotting. Lastly, to understand the observed protective mechanism on BBB functions by fasudil we examined the role of cyclooxygenase-2 and thromboxane A2 receptor agonist U-46619 in BBB-forming cells. Results We found that treatment with 0.3–30 µM of fasudil increased cellular impedance. Fasudil enhanced barrier properties in a concentration-dependent manner, as measured by an increased (TEER) and decreased permeability. Fasudil also increased the expression of tight junction protein claudin-5. Reductions in TEER and increased permeability were observed after OGD/reoxygenation exposure in mono- and co-culture models. The improvement in BBB integrity by fasudil was confirmed in both of the models, but was significantly higher in the co-culture than in the monoculture model. Treatment with U-46619 did not show significant changes in TEER in the monoculture model, whereas it showed a significant reduction in TEER in the co-culture model. Fasudil significantly improved the U-46619-induced TEER reduction in the co-culture models. Pericytes and astrocytes have opposite effects on endothelial cells and may contribute to endothelial injury in hyperacute ischemic stroke. Overall, fasudil protects the integrity of BBB both by a direct protective effect on endothelial cells and by a pathway mediated via pericytes and astrocytes. Conclusions Our findings suggest that fasudil is a BBB-protective agent against acute ischemic stroke.


1996 ◽  
Vol 1 (4) ◽  
pp. E3 ◽  
Author(s):  
Kevin R. Lee ◽  
Nobuyuki Kawai ◽  
Seoung Kim ◽  
Oren Sagher ◽  
Julian T. Hoff

Recently, the authors showed that thrombin contributes to the formation of brain edema following intracerebral hemorrhage. The current study examines whether the action of thrombin is due to an effect on cerebral blood flow (CBF), vasoreactivity, blood-brain barrier (BBB) function, or cell viability. In vivo solutions of thrombin were infused stereotactically into the right basal ganglia of rats. The animals were sacrificed 24 hours later; CBF and BBB permeability were measured. The actions of thrombin on vasoreactivity were examined in vitro by superfusing thrombin on cortical brain slices while monitoring microvessel diameter with videomicroscopy. In separate experiments C6 glioma cells were exposed to various concentrations of thrombin and lactate dehydrogenase release, a marker of cell death, was measured. The results indicate that thrombin induces BBB disruption as well as death of parenchymal cells, whereas CBF and vasoreactivity are not altered. The authors conclude that cell toxicity and BBB disruption by thrombin are triggering mechanisms for the edema formation that follows intracerebral hemorrhage.


2005 ◽  
Vol 289 (2) ◽  
pp. H738-H743 ◽  
Author(s):  
Tracy A. Brooks ◽  
Brian T. Hawkins ◽  
Jason D. Huber ◽  
Richard D. Egleton ◽  
Thomas P. Davis

The blood-brain barrier (BBB) maintains brain homeostasis by limiting entry of substances to the central nervous system through interaction of transmembrane and intracellular proteins that make up endothelial cell tight junctions (TJs). Recently it was shown that the BBB can be modulated by disease pathologies including inflammatory pain. This study examined the effects of chronic inflammatory pain on the functional and molecular integrity of the BBB. Inflammatory pain was induced by injection of complete Freund's adjuvant (CFA) into the right plantar hindpaw in female Sprague-Dawley rats under halothane anesthesia; control animals were injected with saline. Edema and hyperalgesia were assessed by plethysmography and infrared paw-withdrawal latency. At 72 h postinjection, significant edema formation and hyperalgesia were noted in the CFA-treated rats. Examination of permeability of the BBB by in situ perfusion of [14C]sucrose while rats were under pentobarbital anesthesia demonstrated that CFA treatment significantly increased brain sucrose uptake. Western blot analysis of BBB TJ proteins showed no change in expression of zonula occludens-1 (an accessory protein) or actin (a cytoskeletal protein) with CFA treatment. Expression of the transmembrane TJ proteins occludin and claudin-3 and -5 significantly changed with CFA treatment with a 60% decrease in occludin, a 450% increase in claudin-3, and a 615% increase in claudin-5 expression. This study demonstrates that during chronic inflammatory pain, alterations in BBB function are associated with changes in specific transmembrane TJ proteins.


2011 ◽  
Vol 114 (1) ◽  
pp. 92-101 ◽  
Author(s):  
Tetsuhiro Higashida ◽  
Christian W. Kreipke ◽  
José A. Rafols ◽  
Changya Peng ◽  
Steven Schafer ◽  
...  

Object The present study investigated the role of hypoxia-inducible factor-1α (HIF-1α), aquaporin-4 (AQP-4), and matrix metalloproteinase-9 (MMP-9) in blood-brain barrier (BBB) permeability alterations and brain edema formation in a rodent traumatic brain injury (TBI) model. Methods The brains of adult male Sprague-Dawley rats (400–425 g) were injured using the Marmarou closed-head force impact model. Anti–AQP-4 antibody, minocycline (an inhibitor of MMP-9), or 2-methoxyestradiol (2ME2, an inhibitor of HIF-1α), was administered intravenously 30 minutes after injury. The rats were killed 24 hours after injury and their brains were examined for protein expression, BBB permeability, and brain edema. Expression of HIF-1α, AQP-4, and MMP-9 as well as expression of the vascular basal lamina protein (laminin) and tight junction proteins (zona occludens-1 and occludin) was determined by Western blotting. Blood-brain barrier disruption was assessed by FITC-dextran extravasation, and brain edema was measured by the brain water content. Results Significant (p < 0.05) edema and BBB extravasations were observed following TBI induction. Compared with sham-operated controls, the injured animals were found to have significantly (p < 0.05) enhanced expression of HIF-1α, AQP-4, and MMP-9, in addition to reduced amounts (p < 0.05) of laminin and tight junction proteins. Edema was significantly (p < 0.01) decreased after inhibition of AQP-4, MMP-9, or HIF-1α. While BBB permeability was significantly (p < 0.01) ameliorated after inhibition of either HIF-1α or MMP-9, it was not affected following inhibition of AQP-4. Inhibition of MMP reversed the loss of laminin (p < 0.01). Finally, while inhibition of HIF-1α significantly (p < 0.05) suppressed the expression of AQP-4 and MMP-9, such inhibition significantly (p < 0.05) increased the expression of laminin and tight junction proteins. Conclusions The data support the notion that HIF-1α plays a role in brain edema formation and BBB disruption via a molecular pathway cascade involving AQP-4 and MMP-9. Pharmacological blockade of this pathway in patients with TBI may provide a novel therapeutic strategy.


2010 ◽  
Vol 30 (11) ◽  
pp. 1847-1859 ◽  
Author(s):  
Colin L Willis ◽  
Diana S Meske ◽  
Thomas P Davis

Hypoxia (Hx) is a component of many disease states including stroke. Ischemic stroke occurs when there is a restriction of cerebral blood flow and oxygen to part of the brain. During the ischemic, and subsequent reperfusion phase of stroke, blood–brain barrier (BBB) integrity is lost with tight junction (TJ) protein disruption. However, the mechanisms of Hx and reoxygenation (HR)-induced loss of BBB integrity are not fully understood. We examined the role of protein kinase C (PKC) isozymes in modifying TJ protein expression in a rat model of global Hx. The Hx (6% O2) induced increased hippocampal and cortical vascular permeability to 4 and 10 kDa dextran fluorescein isothiocyanate (FITC) and endogenous rat-IgG. Cortical microvessels revealed morphologic changes in nPKC-θ distribution, increased nPKC-θ and aPKC-ζ protein expression, and activation by phosphorylation of nPKC-θ (Thr538) and aPKC-ζ (Thr410) residues after Hx treatment. Claudin-5, occludin, and ZO-1 showed disrupted organization at endothelial cell margins, whereas Western blot analysis showed increased TJ protein expression after Hx. The PKC inhibition with chelerythrine chloride (5 mg/kg intraperitoneally) attenuated Hx-induced hippocampal vascular permeability and claudin-5, PKC (θ and ζ) expression, and phosphorylation. This study supports the hypothesis that nPKC-θ and aPKC-ζ signaling mediates TJ protein disruption resulting in increased BBB permeability.


2009 ◽  
Vol 54 (3) ◽  
pp. 1305-1310 ◽  
Author(s):  
Vasilios Pyrgos ◽  
Diane Mickiene ◽  
Tin Sein ◽  
Margaret Cotton ◽  
Andrea Fransesconi ◽  
...  

ABSTRACT Amphotericin B (AMB) is used to treat fungal infections of the central nervous system (CNS). However, AMB shows poor penetration into the CNS and little is known about the factors affecting its permeation through the blood-brain barrier (BBB). Therefore, we studied immunomodulatory and organism-associated molecules affecting the permeability of an in vitro BBB model to AMB. We examined the effects of interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), lipopolysaccharide (LPS), lipoteichoic acid (LTA), zymosan (ZYM), dexamethasone (DEX), cyclosporine, and tacrolimus on transendothelial electrical resistance (TEER); endothelial tight junctions; filamentous actin; and permeability to deoxycholate AMB (DAMB), liposomal AMB (LAMB), and fluconazole. Proinflammatory cytokines and organism-associated molecules significantly decreased the mean TEER by 40.7 to 100% (P ≤ 0.004). DEX increased the mean TEER by 18.2 to 26.4% (P ≤ 0.04). TNF-α and LPS increased the permeability to AMB by 8.2 to 14.5% compared to that for the controls (1.1 to 2.4%) (P ≤ 0.04). None of the other molecules affected the model's permeability to AMB. By comparison, the BBB model's permeability to fluconazole was >78% under all conditions studied, without significant differences between the controls and the experimental groups. LPS and TNF-α decreased tight-junction protein zona occludens 1 (ZO-1) between endothelial cells. In conclusion, IL-1β, ZYM, and LTA increased the permeability of the BBB to small ions but not to AMB, whereas TNF-α and LPS, which disrupted the endothelial layer integrity, increased the permeability to AMB.


2021 ◽  
Author(s):  
shu wen deng ◽  
Qing Hu ◽  
Qiang He ◽  
Xi qian Chen ◽  
Qiang Lei ◽  
...  

Abstract Background Impairment of the blood-brain barrier after intracerebral hemorrhage (ICH) can lead to secondary brain injury and aggravate neurological deficits. Owing in part to our lack of understanding of the mechanism of ICH injury to the blood-brain barrier, there are currently no effective methods to prevent or treat it. Here, we explored the effects of Golgi apparatus protein GM130 overexpression or silencing on the blood-brain barrier and neurological function after ICH, to better understand the mechanism involved and facilitate the development of new therapeutic methods. Results Levels of the tight junction-associated proteins ZO-1 and occludin decreased, while those of LC3-II, a marker for autophagosomes, increased in hemin-treated Bend.3 cells (p < 0.05). The levels of ZO-1 and occludin increased, while those of LC3-II decreased with GM130 overexpression (p < 0.05). ZO-1 and occludin expression decreased and LC3-II increased after siGM130 transfection, mimicking the effect of hemin (p < 0.05). Tight junctions were disconnected after hemin or siGM130 treatment and repaired with GM130 overexpression. siGM130 transfection in Bend.3 cells increased autophagy flux, whereas GM130 overexpression downregulated autophagy flux. Similar results were verified in an in vivo ICH model. Perihematomal ZO-1 and occludin expression increased, while LC3-II expression decreased in ICH rats (p < 0.05). ZO-1 and occluding expression further decreased and LC3-II expression increased in siGM130-treated ICH rats (p < 0.05), whereas a reverse effect was observed in AAV-GM130-treated ICH rats (p < 0.05). Perihematomal Evans blue and brain water content were much higher in siGM130-treated ICH rats than in the control ICH rats. AAV-GM130-treated ICH rats showed a lower perihematomal Evans blue and brain water content than the control ICH rats. Conclusions GM130 overexpression can protect the integrity of the blood-brain barrier from brain injury, inhibit excessive autophagy flux in an ICH in vivo model, and further improve the neurobehavioral prognosis. GM130 overexpression may mediate tight junction protein repair by directly reducing autophagy flux in an ICH in vitro model. GM130 may be a therapeutic target for acute brain injury after ICH.


Stroke ◽  
2015 ◽  
Vol 46 (suppl_1) ◽  
Author(s):  
Kyeong-A Kim ◽  
Young-Jun Shin ◽  
Eun-Sun Kim ◽  
Muhammad Akram ◽  
Dabi Noh ◽  
...  

During ischemic stroke, the integrity of blood-brain barrier (BBB), which shows selective permeability for substances to brain, is significantly damaged amplifying ischemic neuronal damage. There have been attempts to identify the exact mechanism ischemic BBB disruption to minimize brain damage under ischemic stroke. Autophagy is catabolic process which involves degradation and recycling of damaged or unnecessary organelles. However, excessive autophagy can induce cell damage and death under pathological conditions such as ischemia. In this study, we evaluated if autophagy is a key mechanism of BBB dysfunction under ischemic stroke. In vitro BBB model of bEnd.3 cells were exposed to oxygen-glucose deprivation (OGD), an ischemic mimic condition. After exposure to OGD for 18 hours, cell viability was significantly decreased and cellular permeability was impaired. The conversion of LC3-I to LC3-II and puncta of LC3 in bEnd.3 were increased, demonstrating that autophagy is induced under ischemic condition. Modulation of autophagy by 3-methyladenine, an autophagy inhibitor, reversed the conversion of LC3 as well as decreased cell viability, suggesting that autophagy involves in ischemic BBB damage. The level of occludin, a tight junction protein in BBB, was decreased after OGD, and this was reversed by inhibition of autophagy. Our findings showed that induction of autophagy might contribute to increased permeability through occludin degradation in brain endothelial cells under ischemia, providing a new mechanism of BBB disruption in ischemic stroke.


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