ICH-induced Neurological Deficits Research Articles

The Neuroprotective Effects and Probable Mechanisms of Everolimus in a Rat Model of Intracerebral Hemorrhage.

Mammalian target of rapamycin (mTOR) is a central regulator of cellular growth and homeostasis. Changes in mTOR activity are often observed in many neurological diseases, such as stroke. Intracerebral hemorrhage (ICH) is associated with high mortality and morbidity. However, there are currently no treatments that have been shown to enhance outcomes following ICH, so new treatments are urgently required. In this study, a selective mTOR inhibitor, everolimus, was applied to investigate the outcome after ICH and the possible underlying mechanism. The ICH model was established by autologous blood injection. Everolimus (50 and 100µg/kg) was administered intraperitoneally for 14 consecutive days' post-operation. The neurological functions were examined at 3, 7, and 14days' post-ICH. Samples of brain tissue were collected to perform histopathological and immunohistochemical (NF-k-positive cell) examinations. Besides, the striatum was used to evaluate parameters related to oxidative stress (superoxide dismutase (SOD) activity, malondialdehyde (MDA), and total thiol levels) and inflammation markers (TNF-α and NO). Everolimus ameliorated ICH-induced neurological deficits. In addition, treatment with everolimus reduced infarct volume and NF-k-β positive cells as compared to the ICH group. Furthermore, everolimus significantly increased total thiol content and SOD activity while significantly reducing MDA, NO, and TNF- levels as compared to the ICH group. Collectively, our investigation showed that everolimus improves ICH outcome and modulates oxidative stress and inflammation after ICH. Treatment with rapamycin reduced neurological deficient, oxidative stress, and inflammation in a rat model of intracerebral hemorrhage.

Caveolin-1 aggravates neurological deficits by activating neuroinflammation following experimental intracerebral hemorrhage in rats

BackgroundIntracerebral hemorrhage (ICH) is one of the stroke subtypes with the highest mortality. Secondary brain injury is associated with neurological dysfunction and poor prognosis after ICH. Caveolin-1 (CAV1) is the key protein of Caveolae. Previous studies have shown that CAV1 plays an important role in central nervous system diseases, and pointed out that in a collagenase-induced ICH model in vivo, CAV1 is associated with neuroinflammatory activation and poor neurological prognosis. In this study, we explore the role and the molecular mechanism of CAV1 in brain injury via a rat autologous whole blood injection model and an in vitro model of ICH. MethodsAdult male Sprague-Dawley rats ICH model was induced through autologous whole blood injecting into the right basal ganglia. The changes in protein levels of CAV1 in brain tissues of ICH rats were detected by western blot analysis. The immunofluorescent staining was used to explore the changes of CAV1 in microglia/macrophages (Iba1+ cells). Lentivirus vectors were administered by intracerebroventricular injection to induce CAV1 overexpression and knockdown respectively. The western blot analysis, immunofluorescence staining, enzyme-linked immunosorbent assay, terminal deoxynucleotidyl transferase dUTP nick end labeling and Nissl staining were performed to explore the role of CAV1 in secondary brain injury after ICH. Meanwhile, the rotarod test, foot fault test, adhesive-removal test, and Modified Garcia Test, as well as Morris Water Maze test, were performed to evaluate the behavioral cognitive impairment of ICH rats after genetic intervention. Additionally, BV-2 cells treated with oxygen hemoglobin for 24 h, were used as an in vitro model of ICH in this study to explore the molecular mechanism of CAV1 in brain injury; we performed western blot analysis after precise regulation of CAV1 in BV2 cells to observe changes in protein levels and phosphorylated levels of C-Src, IKK-β, and NF-κB. ResultsThe expression of CAV1 in microglia/macrophages (Iba1+ cells) was elevated and reached the peak at 24 h after ICH. CAV1 knockdown ameliorated ICH-induced neurological deficits, while CAV1 overexpression significantly worsened neurological dysfunction of ICH rats. CAV1 knockdown attenuated cellular apoptosis and promoted neuronal survival in brain tissues of ICH rats, while the ICH rats with CAV1 overexpression presented more cellular apoptosis and neuronal loss. Meanwhile, CAV1 knockdown inhibited the microglia activation and neuroinflammatory response, while CAV1 overexpression abolished these effects and aggravated neuroinflammation in brain tissues of ICH rats. Additionally, by inducing to CAV1 knockdown in BV2 cells in an in vitro model of ICH, the levels of p-C-Src, CAV-1, p-CAV-1, and p-IKK-β in cytoplasm and the level of NF-κB p65 in nucleus of BV2 cells were significantly decreased, while they were increased by inducing to CAV1 overexpression. ConclusionsOur research revealed CAV1 aggravated neurological dysfunction in a rat ICH model. CAV1 knockdown exerted neuroprotective effect by suppressing microglia activation and neuroinflammation after ICH might via the C-Src/CAV1/IKK-β/NF-κB signaling pathway.

Dexmedetomidine post-conditioning protects blood-brain barrier integrity by modulating microglia/macrophage polarization via inhibiting NF-κB signaling pathway in intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is one of the most devastating forms of stroke. Dexmedetomidine (DEX) has shown certain neuroprotective roles in ICH. Nevertheless, the details concerning the underlying molecular mechanism of DEX’s protective effects still need further elucidation. Herein, a model of ICH was established. The rats were randomly divided into the sham group, the ICH group, and the ICH + DEX group. Neurological outcomes, neuronal injury, and apoptosis were evaluated. Brain water content, Evans blue extravasation, and the expression of tight junction-associated proteins were also detected to assess the blood-brain barrier (BBB) integrity. Subsequently, the microglia/macrophage polarization state and inflammatory cytokine levels were observed. To further explore the underlying mechanism, NF-κB signaling pathway-associated proteins were detected. The results showed that DEX exerted neuroprotective effects against ICH-induced neurological deficits. DEX significantly increased the numbers of the surviving neurons and ameliorated neuronal cell loss and apoptosis in ICH. The rats that received the DEX displayed a lower level of brain water content and EB extravasation, moreover, ZO-1, occludin, and claudin-5 were markedly increased by DEX. Additionally, DEX facilitated M2 microglia/macrophage polarization, the M1-associated markers were reduced by DEX, while the M2-associated identification significantly increased. We found that DEX dramatically diminished pro-inflammatory cytokines expression, simultaneously promoting anti-inflammatory cytokines expression. DEX inhibited nuclear translocation of NF-κB in ICH rats. Our data suggest that DEX post-conditioning protects BBB integrity by modulating microglia/macrophage polarization via inhibiting the NF-κB signaling pathway in ICH.

Berberine Protects against Neurological Impairments and Blood-Brain Barrier Injury in Mouse Model of Intracerebral Hemorrhage

Background: Elevation of AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) signaling can suppress intracerebral hemorrhage (ICH)-induced neurological impairments. As an isoquinoline alkaloid, Berberine exerts neuroprotective effects in neurological disease models with activated AMPK/PGC1α signaling. Aim: We aim to study the effect of Berberine on ICH-induced brain injury and explore the potential molecular mechanism. Methods: ICH model was established in mice through intracerebral injection of autologous whole blood, followed by treatment with Berberine. Neurological impairments were assessed by the modified neurological severity score and behavioral assays. Brain edema and blood-brain barrier (BBB) integrity were assessed by water content in the brain, amount of extravasated Evans blue, and BBB tight junction components. Neuroinflammatory responses were assessed by inflammatory cytokine levels. AMPK/PGC1α signaling was examined by AMPK mRNA expression and phosphorylated AMPK and PGC1α protein levels. Results: Berberine (200 mg/kg) attenuated ICH-induced neurological deficits, motor and cognitive impairment, and BBB disruption. Berberine also suppressed ICH-induced inflammatory responses indicated by reduced production of inflammatory cytokines. Finally, Berberine drastically elevated AMPK/PGC1α signaling in the hemisphere of ICH mice. Conclusion: Our findings suggest that Berberine plays an important neuroprotective role against ICH-induced neurological impairments and BBB injury, probably by inhibition of inflammation and activation of AMPK/PGC1α signaling.

Cordycepin Ameliorates Intracerebral Hemorrhage Induced Neurological and Cognitive Impairments Through Reducing Anti-Oxidative Stress in a Mouse Model

ObjectivesThe nerve damage and cognitive impairment caused by intracerebral hemorrhage (ICH) seriously affect the quality of life of patients. Cordycepin has been reported to have antioxidant and neuroprotective functions. However, the therapeutic effect of cordycepin on cognitive impairment caused by ICH is still unclear. Materials and methodsAutologous whole blood was injected into the basal ganglia to construct a mouse ICH model. The Modified Neurological Severity Score was used to assess nerve damage in mice. The wet/dry method was used to detect brain water content. Open field test was used to assess the anxiety of mice. Morris water maze testing, Y-maze test and nest-building test were used to evaluate the cognitive function of mice. qRT-PCR and western blotting assay were used to evaluate the expression of genes. ResultsCordycepin treatment could ameliorate ICH-induced neurological deficits, brain edema, anxiety, cognitive impairments, oxidative stress and antioxidant capacity in ICH mice. ConclusionCordycepin ameliorates ICH-induced neurological and cognitive impairments through reducing anti-oxidative stress in mouse model.

Acupuncture inhibits mammalian target of rapamycin, promotes autophagy and attenuates neurological deficits in a rat model of hemorrhagic stroke.

Intracerebral hemorrhage (ICH) accounts for approximately 15% of all stroke cases. Previous studies suggested that acupuncture may improve ICH-induced neurological deficits. Therefore, we investigated the effects of acupuncture on neurological deficits in an animal model of ICH. Adult male Sprague-Dawley rats were injected with autologous blood (50 μL) into the right caudate nucleus. Additional rats underwent sham surgery as controls. ICH rats either received acupuncture (GV20 through GB7 on the side of the lesion) or sham acupuncture (1 cm to the right side of the traditional acupuncture point locations). Some ICH rats received acupuncture plus rapamycin injection into the right lateral ventricle. Neurological deficits in the various groups were assessed based on composite neurological score. The perihemorrhagic penumbra was analyzed by histopathology following hematoxylin-eosin staining. Levels of autophagy-related proteins light chain (LC)3 and p62 as well as of mammalian target of rapamycin (mTOR)-related proteins, and phosphorylated (p)-mTOR and p-S6K1 (ribosomal protein S6 kinase beta-1), were assessed by Western blotting. Acupuncture significantly improved composite neurological scores 7 days after ICH (17.7 ± 1.49 vs 14.8 ± 1.32, p < 0.01). Acupuncture augmented autophagosome and autolysosome accumulation based on transmission electron microscopy. Acupuncture significantly increased expression of LC3 (p < 0.01) but decreased expression of p62 (p < 0.01). Acupuncture also reduced levels of p-mTOR and p-S6K1 (both p < 0.01). Acupuncture improved neurological deficits in a rat model of ICH, possibly by inhibiting the mTOR pathway and activating autophagy.

Puerarin attenuates intracerebral hemorrhage-induced early brain injury possibly by PI3K/Akt signal activation-mediated suppression of NF-κB pathway.

Intracerebral hemorrhage (ICH) can induce intensively oxidative stress, neuroinflammation, and brain cell apoptosis. However, currently, there is no highly effective treatment available. Puerarin (PUE) possesses excellent neuroprotective effects by suppressing the NF‐κB pathway and activating the PI3K/Akt signal, but its role and related mechanisms in ICH‐induced early brain injury (EBI) remain unclear. In this study, we intended to observe the effects of PUE and molecular mechanisms on ICH‐induced EBI. ICH was induced in rats by collagenase IV injection. PUE was intraperitoneally administrated alone or with simultaneously intracerebroventricular injection of LY294002 (a specific inhibitor of the PI3K/Akt signal). Neurological deficiency, histological impairment, brain edema, hematoma volume, blood–brain barrier destruction, and brain cell apoptosis were evaluated. Western blot, immunohistochemistry staining, reactive oxygen species (ROS) measurement, and enzyme‐linked immunosorbent assay were performed. PUE administration at 50 mg/kg and 100 mg/kg could significantly reduce ICH‐induced neurological deficits and EBI. Moreover, PUE could notably restrain ICH‐induced upregulation of the NF‐κB pathway, pro‐inflammatory cytokines, ROS level, and apoptotic pathway and activate the PI3K/Akt signal. However, LY294002 delivery could efficaciously weaken these neuroprotective effects of PUE. Overall, PUE could attenuate ICH‐induced behavioral defects and EBI possibly by PI3K/Akt signal stimulation‐mediated inhibition of the NF‐κB pathway, and this made PUE a potential candidate as a promising therapeutic option for ICH‐induced EBI.

Moderate Ethanol Pre-treatment Mitigates ICH-Induced Injury via ER Stress Modulation in Rats.

Intracerebral hemorrhage (ICH) is a life-threatening type of stroke that disrupts the normal neurological function of the brain. Clinical studies have reported a non-linear J-shaped association between alcohol consumption levels and the occurrence of cerebral stroke. Specifically, alcohol intoxication increases stroke incidence, while moderate alcohol pre-conditioning decreases stroke frequency and improves outcomes. Although alcohol pre-consumption is likely a crucial player in ICH, the underlying mechanism remains unclear. We performed 1-h alcohol pre-conditioning followed by ICH induction in Sprague-Dawley (SD) rats to investigate the role of alcohol pre-conditioning in ICH. Interestingly, behavioral test analysis found that ethanol intoxication (3 g/kg) aggravated ICH-induced neurological deficits, but moderate ethanol pre-conditioning (0.75 g/kg) ameliorated ICH-induced neurological deficits by reducing the oxidative stress and proinflammatory cytokines release. Moreover, we found that moderate ethanol pretreatment improved the striatal endoplasmic reticulum (ER) homeostasis by increasing the chaperone protein expression and reducing oxidative stress and apoptosis caused by ICH. Our findings show that the mechanism regulated by moderate ethanol pre-conditioning might be beneficial for ICH, indicating the importance of ER homeostasis, oxidative stress, and differential cytokines release in ICH.

Mature Adult Mice With Exercise-Preconditioning Show Better Recovery After Intracerebral Hemorrhage.

Physical exercise offers therapeutic potentials for several central nervous system disorders, including stroke and cardiovascular diseases. However, it is still mostly unknown whether and how exercise preconditioning affects the prognosis of intracerebral hemorrhage (ICH). In this study, we examined the effects of preconditioning on ICH pathology in mature adult mice using treadmill exercise. Male C57BL/6J (25-week old) mice were subjected to 6 weeks of treadmill exercise followed by ICH induction. Outcome measurements included various neurological function tests at multiple time points and the assessment of lesion volume at 8 days after ICH induction. In addition, plasma soluble factors and phagocytotic microglial numbers in the peri-lesion area were also measured to determine the mechanisms underlying the effects of exercise preconditioning. The 6-week treadmill exercise preconditioning promoted recovery from ICH-induced neurological deficits in mice. In addition, mice with exercise preconditioning showed smaller lesion volumes and increased numbers of phagocytotic microglia. Furthermore, the levels of several soluble factors, including endostatin, IGFBP (insulin-like growth factor-binding protein)-2 and -3, MMP (matrix metallopeptidase)-9, osteopontin, and pentraxin-3, were increased in the plasma samples from ICH mice with exercise preconditioning compared with ICH mice without exercise. These results suggest that mice with exercise preconditioning may suffer less severe injury from hemorrhagic stroke, and therefore, a habit of physical exercise may improve brain health even in middle adulthood.

17β-Estradiol Attenuates Intracerebral Hemorrhage-Induced Blood-Brain Barrier Injury and Oxidative Stress Through SRC3-Mediated PI3K/Akt Signaling Pathway in a Mouse Model.

Estrogen is neuroprotective in brain injury models, and steroid receptor cofactor 3 (SRC3) mediates estrogen signaling. We aimed to investigate whether and how SRC3 is involved in the neuroprotective effects of 17ß-estradiol (E2) in a mouse model of intracerebral hemorrhage (ICH). Ovariectomized female mice were treated with E2 after autologous blood injection-induced ICH. Brain damage was assessed by neurological deficit score, brain water content, and oxidative stress levels. Blood–brain barrier (BBB) integrity was evaluated by Evan's blue extravasation and claudin-5, ZO-1, and occludin levels. SRC3 expression and PI3K/Akt signaling pathway were examined in ICH mice treated with E2. The effect of SRC3 on E2-mediated neuroprotection was determined by examining neurological outcomes in SRC3-deficient mice undergone ICH and E2 treatment. We found that E2 alleviated ICH-induced brain edema and neurological deficits, protected BBB integrity, and suppressed oxidative stress. E2 enhanced SRC3 expression and PI3K-/Akt signaling pathway. SRC3 deficiency abolished the protective effects of E2 on ICH-induced neurological deficits, brain edema, and BBB integrity. Our results suggest that E2 suppresses ICH-induced brain injury and SRC3 plays a critical role in E2-mediated neuroprotection.

Arundic Acid (ONO-2506), an Inhibitor of S100B Protein Synthesis, Prevents Neurological Deficits and Brain Tissue Damage Following Intracerebral Hemorrhage in Male Wistar Rats

Stroke is one of the leading causes of mortality and neurological morbidity. Intracerebral hemorrhage (ICH) has the poorest prognosis among all stroke subtypes and no treatment has been effective in improving outcomes. Following ICH, the observed high levels of S100B protein have been associated with worsening of injury and neurological deficits. Arundic acid (AA) exerts neuroprotective effects through inhibition of astrocytic synthesis of S100B in some models of experimental brain injury; however, it has not been studied in ICH. The aim of this study was to evaluate the effects of intracerebroventricular (ICV) administration of AA in male Wistar rats submitted to ICH model assessing the following variables: reactive astrogliosis, S100B levels, antioxidant defenses, cell death, lesion extension and neurological function. Firstly, AA was injected at different doses (0.02, 0.2, 2 and 20 μg/μl) in the left lateral ventricle in order to observe which dose would decrease GFAP and S100B striatal levels in non-injured rats. Following determination of the effective dose, ICH damage was induced by IV-S collagenase intrastrial injection and 2 μg/μl AA was injected through ICV route immediately before injury. AA treatment prevented ICH-induced neurological deficits and tissue damage, inhibited excessive astrocytic activation and cellular apoptosis, reduced peripheral and central S100B levels (in striatum, serum and cerebrospinal fluid), improved neuronal survival and enhanced the antioxidant defences after injury. Altogether, these results suggest that S100B is a viable target for treating ICH and highlight AA as an interesting strategy for improving neurological outcome after experimental brain hemorrhage.

Intravenous administration of human amnion-derived stem cells improves neurobehavioral function in intracerebral hemorrhage mouse models by regulating inflammation and inhibition of apoptosis

Background & Aim Intracerebral hemorrhage (ICH) causes disabilities and its functional recovery by rehabilitations is limited. Recently, various stem cell therapies have been reported in animal model of ICH. Intravenous administration of mesenchymal stem cells was reported to be effective in some animal studies. The possible mechanisms of improvement are anti-inflammation and/or anti-edema effect by macrophage polarization. Here we report the effect of human amnion-derived stem cells (hAMSCs) on neurological improvement using the mouse cerebral hemorrhage model as a preclinical test. Methods, Results & Conclusion Methods: Using seven to nine-week-old male C57BL/6J mice, ICH model was made by injecting 0.4U of collagenase into the brain, which located 2 mm to the left side and 3.5 mm depth from the bregma. Mice were divided into the following four group, The Day (D) 1-hAMSC and D3 hAMSC groups received an intravenous injection of hAMSC (105 cells/ 50ul) 24 and 72 hour after the ICH induction respectively; the D3 Vehicle group received an intravenous injection of 50 ul vehicle. We also prepared the sham group with scalp incision and trepanation. From Day 29 and later on, mice were evaluated for phenotypical differences for the following neurobehavioral tests: wire hang, water maze learning, passive avoidance learning, and open space swimming. Immunostaining assay, TUNEL assay and molecular biology assay was performed for researching the mechanisms. Result The hAMSCs administration into the ICH mice improved the neurological function at the subacute phases, which was shown by neurobehavioral experiments. The improvement is particularly remarkable in the D1-hAMSC groups. Besides, the hAMSCs administration decreased the number of CD11+CD45+ cells, Ly6G+ cells, TUNEL positive cells and expression of EGF, CD11c and IL23p19 in the ICH lesions. Conclusion Intravenous administration of hAMSCs during the acute phase improved ICH-induced neurological deficits at the subacute phase because of the regulation of acute inflammation and suppression of apoptosis.

Intracerebral Hemorrhage: Blood Components and Neurotoxicity.

Intracerebral hemorrhage (ICH) is a subtype of stroke which is associated with the highest mortality and morbidity rates of all strokes. Although it is a major public health problem, there is no effective treatment for ICH. As a consequence of ICH, various blood components accumulate in the brain parenchyma and are responsible for much of the secondary brain damage and ICH-induced neurological deficits. Therefore, the strategies that could attenuate the blood component-induced neurotoxicity and improve hematoma resolution are highly needed. The present article provides an overview of blood-induced brain injury after ICH and emphasizes the need to conduct further studies elucidating the mechanisms of hematoma resolution after ICH.

Inhibition of neuronal ferroptosis in the acute phase of intracerebral hemorrhage shows long-term cerebroprotective effects

Intracerebral hemorrhage (ICH) is a devastating subtype of stroke because it has few viable therapeutic options to intervene against primary or second brain injury. Recently, evidence has suggested that ferroptosis, a nonapoptotic form of cell death, is involved in ICH. In this study, we examined whether ICH-induced neuron death is partly ferroptotic in humans and assessed its temporal and spatial characteristics in mice. Furthermore, the ferroptosis inhibitor ferrostatin-1 (Fer-1) was used to examine the role of ferroptosis after ICH. Fold changes in ferroptosis-related gene expression, intracellular iron levels, malondialdehyde (MDA) levels, and both protein levels and cellular localization of cyclooxygenase-2 (COX-2) were measured to monitor ferroptosis. Transmission electron microscopy (TEM) was also performed to examine the ultrastructure of cells after ICH. We found that the expression level of prostaglandin-endoperoxide synthase (PTGS2) was increased in both in vitro and in vivo ICH models; by comparison, expression level of RPL8 was increased in human brain tissue. In mice, iron and MDA levels were significantly increased 3 h after ICH; COX-2 levels were increased at 12 h after ICH and peaked at 3 days after ICH; COX-2 colocalized with NeuN (a neuronal biomarker); and TEM showed that shrunken mitochondria were found at 3 h, 3 days, and 7 days after ICH. Moreover, ICH-induced neurological deficits, memory impairment and brain atrophy were reduced by Fer-1 treatment. Our results demonstrated that neuronal ferroptosis occurs during the acute phase of ICH in brain areas distant from the hematoma and that inhibition of ferroptosis by Fer-1 exerted a long-term cerebroprotective effect.

Neuroprotective potential of GDF11 in experimental intracerebral hemorrhage in elderly rats

The occurrence of intracerebral hemorrhage (ICH) costs long-standing neurologic deficits in ICH survivors, elderly ones in particular. Recent researches have proved rejuvenating effect of Growth Differentiation Factor 11 (GDF11) in improving multiple systemic diseases on old individuals. Thus, we designed this study to explore the neuroprotective effect and mechanisms of GDF11 in elderly ICH. 45 aged male Sprague-Dawley (SD) rats were randomly divided into sham + vehicle, ICH + vehicle and ICH + rGDF11 groups. ICH models were induced via injection of autologous whole blood into right basal ganglia of rats. ICH rats were given a daily injection of either recombinant (r) GDF11 at 0.1 mg/kg or vehicle for 28 days prior to operation and continued till the experiment completed. Neurological deficits, brain edema, cell apoptosis, microglial activation and heme oxygenase-1 (HO-1) positive cells were compared among each group. In addition, cytochrome c release, mitochondrial calcium buffering capacity and ATP level were monitored to explore the level of mitochondrial injury. Seen in the result, behavior disorders, severe perihematomal edema, inflammation, apoptosis, oxidative stress and mitochondria damage indicated a significant increase in ICH + vehicle group. While in ICH + rGDF11 group, administration of rGDF11 successfully reduced neurological deficits and alleviated ICH-induced edema, inflammation, apoptosis, oxidative stress, and mitochondria damage in perihematomal tissues. Collectively, our study showed that GDF11 ameliorated ICH-induced neurological deficits in elderly individuals via reducing perihematomal edema, apoptosis, inflammatory reaction, oxidative stress and improving mitochondrial dysfunction, indicating neuroprotective effect of GDF11 in elderly ICH.

Dexmedetomidine Protects Against Neurological Dysfunction in a Mouse Intracerebral Hemorrhage Model by Inhibiting Mitochondrial Dysfunction-Derived Oxidative Stress

BackgroundIntracerebral hemorrhage (ICH) is a subtype of stroke with high disability and mortality. Dexmedetomidine (Dex) has been shown to provide neuroprotection in several neurological diseases. The aim of present study was to investigate the effects of Dex on ICH-induced neurological deficits and brain injury and the underlying mechanisms. MethodsICH mouse model was established by intracerebral injection of autologous blood, followed by Dex or vehicle treatment. Neurological function, brain water content, neuronal activity, and oxidative parameters were determined. The protein expressions of peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α), uncoupling protein 2, and manganese-dependent superoxide dismutase were examined by western blotting. ResultsDex administration significantly inhibited ICH-induced the memory impairment, dyskinesia, brain edema, and neuron loss. In addition, ICH-induced the increase in brain oxidative stress level was markedly attenuated after Dex treatment, as evidenced by increased glutathione peroxidase and superoxide dismutase levels and reduced malondialdehyde and nitric oxide levels. Compared with vehicle-treated ICH mice, Dex-treated ICH mice showed significantly decreased intracellular reactive oxygen species (ROS) and mitochondrial ROS (mROS) production in brain, but had no effects on the increased nicotinamide-adenine dinucleotide phosphate oxidase activity. However, stimulation of mROS abrogated the inhibitory effects of Dex on neurological deficits and oxidative stress. The decrease in production of adenosine triphosphate and the expressions of PGC-1α, uncoupling protein 2, and manganese-dependent superoxide dismutase induced by ICH was restored by Dex treatment. ConclusionsOur results reveal that Dex improves ICH-induced neurological deficits and brain injury by inhibiting PGC-1α pathway inactivation and mitochondrial dysfunction-derived oxidative stress.

Intravenous administration of human adipose-derived stem cells ameliorates motor and cognitive function for intracerebral hemorrhage mouse model

Even today, intracerebral hemorrhage (ICH) is a major cause of death and disabilities. Rehabilitation is preferentially applied for functional recovery although its effect is limited. Recent studies have suggested that intravenous administration of mesenchymal stem cells would improve the post-ICH neurological deficits. Human adipose-derived stem cells (hADSCs) have been established in our laboratory. We aimed to evaluate the therapeutic efficacy of the hADSCs on the post-ICH neurological deficits using a clinical-relevant ICH mouse model. We also evaluated immune responses to clarify the underlying mechanisms. The hADSCs expressed MSC markers at high levels. The hADSCs administration into the ICH-bearing mice improved the neurological deficits during the subacute phases, which was shown by neurobehavioral experiments. Besides, the hADSC administration decreased the number of CD11+CD45+ cells and increased the proportion of CD86+ and Ly6C+ cells in the ICH lesions. In summary, intravenous administration of hADSCs during the acute phase improved ICH-induced neurological deficits during the subacute phase because of the suppression of acute inflammation mediated by CD11+CD45+ subpopulations. Our data suggest that hADSCs can be served as a novel strategy for ICH treatment.

Minocycline promotes posthemorrhagic neurogenesis via M2 microglia polarization via upregulation of the TrkB/BDNF pathway in rats.

Intracerebral hemorrhage (ICH) is a devastating disease worldwide with increasing mortality. The present study investigated whether minocycline was neuroprotective and induced M2 microglial polarization via upregulation of the TrkB/BDNF pathway after ICH. ICH was induced via injection of autologous blood into 150 Sprague-Dawley rats. A selective TrkB antagonist [N2-2-2-oxoazepan-3-yl amino] carbonyl phenyl benzo (b) thiophene-2-carboxamide (ANA 12)] and agonist [ N-[2-(5-hydroxy-1H-indol-3-yl) ethyl]-2-oxopiperidine-3-carboxamide (HIOC)] were used to investigate the mechanism of minocycline-induced neuroprotection. Minocycline improved ICH-induced neurological deficits and reduced M1 microglia marker protein (CD68, CD16) expression as well as M2 microglial polarization (CD206 and arginase 1 protein). Minocycline administration enhanced microglia-neuron cross talk and promoted the proliferation of neuronal progenitor cells, such as DCX- and Tuj-1-positive cells, 24 h after ICH. Minocycline also increased M2 microglia-derived brain-derived neurotrophic factors (BDNF) and the upstream TrkB pathway. ANA 12 reversed the neuroprotective effects of minocycline. HIOC exhibited the same effects as minocycline and accelerated neurogenesis after ICH. This study demonstrated for the first time that minocycline promoted M2 microglia polarization via upregulation of the TrkB/BDNF pathway and promoted neurogenesis after ICH. This study contributes to our understanding of the therapeutic potential of minocycline in ICH. NEW & NOTEWORTHY The present study gives several novel points: 1) Minocycline promotes neurogenesis after intracerebral hemorrhage in rats. 2) Minocycline induces activated M1 microglia into M2 neurotrophic phenotype. 3) M2 microglia secreting BDNF remodel the damaged neurocircuit.

Toll-like receptor 4 signaling in intracerebral hemorrhage-induced inflammation and injury

Intracerebral hemorrhage (ICH) is a common type of fatal stroke, accounting for about 15% to 20% of all strokes. Hemorrhagic strokes are associated with high mortality and morbidity, and increasing evidence shows that innate immune responses and inflammatory injury play a critical role in ICH-induced neurological deficits. However, the signaling pathways involved in ICH-induced inflammatory responses remain elusive. Toll-like receptor 4 (TLR4) belongs to a large family of pattern recognition receptors that play a key role in innate immunity and inflammatory responses. In this review, we summarize recent findings concerning the involvement of TLR4 signaling in ICH-induced inflammation and brain injury. We discuss the key mechanisms associated with TLR4 signaling in ICH and explore the potential for therapeutic intervention by targeting TLR4 signaling.

Systemic administration of urocortin after intracerebral hemorrhage reduces neurological deficits and neuroinflammation in rats

BackgroundIntracerebral hemorrhage (ICH) remains a serious clinical problem lacking effective treatment. Urocortin (UCN), a novel anti-inflammatory neuropeptide, protects injured cardiomyocytes and dopaminergic neurons. Our preliminary studies indicate UCN alleviates ICH-induced brain injury when administered intracerebroventricularly (ICV). The present study examines the therapeutic effect of UCN on ICH-induced neurological deficits and neuroinflammation when administered by the more convenient intraperitoneal (i.p.) route.MethodsICH was induced in male Sprague-Dawley rats by intrastriatal infusion of bacterial collagenase VII-S or autologous blood. UCN (2.5 or 25 μg/kg) was administered i.p. at 60 minutes post-ICH. Penetration of i.p. administered fluorescently labeled UCN into the striatum was examined by fluorescence microscopy. Neurological deficits were evaluated by modified neurological severity score (mNSS). Brain edema was assessed using the dry/wet method. Blood-brain barrier (BBB) disruption was assessed using the Evans blue assay. Hemorrhagic volume and lesion volume were assessed by Drabkin's method and morphometric assay, respectively. Pro-inflammatory cytokine (TNF-α, IL-1β, and IL-6) expression was evaluated by enzyme-linked immunosorbent assay (ELISA). Microglial activation and neuronal loss were evaluated by immunohistochemistry.ResultsAdministration of UCN reduced neurological deficits from 1 to 7 days post-ICH. Surprisingly, although a higher dose (25 μg/kg, i.p.) also reduced the functional deficits associated with ICH, it is significantly less effective than the lower dose (2.5 μg/kg, i.p.). Beneficial results with the low dose of UCN included a reduction in neurological deficits from 1 to 7 days post-ICH, as well as a reduction in brain edema, BBB disruption, lesion volume, microglial activation and neuronal loss 3 days post-ICH, and suppression of TNF-α, IL-1β, and IL-6 production 1, 3 and 7 days post-ICH.ConclusionSystemic post-ICH treatment with UCN reduces striatal injury and neurological deficits, likely via suppression of microglial activation and inflammatory cytokine production. The low dose of UCN necessary and the clinically amenable peripheral route make UCN a potential candidate for development into a clinical treatment regimen.