Zuohui Zhang

Intranasal administration of human umbilical cord mesenchymal stem cells-conditioned medium enhances vascular remodeling after stroke.

Stem cell-based treatments have been reported to be a potential strategy for stroke. However, tumorigenic potential and low survival rates of transplanted cells could attenuate the efficacy of the stem cell-based treatments. The application of stem cell-condition medium (CM) may be a practicable approach to conquer these limitations. In this study, we investigated whether intranasal administration of human umbilical cord mesenchymal stem cells (hUCMSCs)-CM has the therapeutic effects in rats after stroke. Adult male rats were subjected to middle cerebral artery occlusion (MCAo) and were treated by intranasal routine with or without hUCMSCs-CM (1 ml/kg/d), starting 24h after MCAo and daily for 14 days. Neurological functional tests, blood brain barrier (BBB) leakage, were measured. Angiogenesis and angiogenic factor expression were measured by immunohistochemistry, and Western blot, respectively. hUCMSCs-CM treatment of stroke by intranasal routine starting 24h after MCAo in rats significantly enhances BBB functional integrity and promotes functional outcome but does not decrease lesion volume compared to rats in DMEM/F12 medium control group and saline control group. Treatment of ischemic rats with hUCMSCs-CM by intranasal routine also significantly decreases the levels of Ang2 and increases the levels of both Ang1 and Tie2 in the ischemic brain. To take together, increased expression of Ang1 and Tie2 and decreased expression of Ang2, induced by hUCMSCs-CM treatment, contribute to vascular remodeling in the ischemic brain which plays an important role in functional outcome after stroke.

Purinergic 2X7 receptor/NLRP3 pathway triggers neuronal apoptosis after ischemic stroke in the mouse

ABSTRACT Previous research has shown that Purinergic 2X7 receptor (P2X7R) and NLRP3 inflammasome contribute to the inflammatory activation. In this study, we investigated whether P2X7R/NLRP3 pathway is involved in the caspase‐3 dependent neuronal apoptosis after ischemic stroke by using a focal cortex ischemic stroke model. The expressions of P2X7R, NLRP3 inflammsome components, and cleaved caspase‐3 were significantly enhanced in the ischemic brain tissue after stroke. However, the expression of cleaved caspase‐3 was significantly attenuated after treatment of stroke with P2X7R antagonist (BBG) or NLRP3 inhibitor (MCC950). The treatment also significantly reduced the infarction volume, neuronal apoptosis, and neurological impairment. In addition, in vitro data also support the hypothesis that P2X7R/NLRP3 pathway plays a vital role in caspase‐3 dependent neuronal apoptosis after ischemic stroke. Further investigation of effective regulation of P2X7R and NLRP3 in stroke is warranted. HIGHLIGHTSThe expressions of P2X7R, NLRP3 inflammsome components were increased after stroke.BBG treatment reduced neurological impairment, neuronal apoptosis.MCC950 treatment also reduced neurological impairment, neuronal apoptosis.NLRP3 mediated neuronal apoptosis could be ameliorated by a P2X7R antagonist.In vitro data also supported that P2X7R/NLRP3 pathway triggers neuronal apoptosis.

ROS/TXNIP pathway contributes to thrombin induced NLRP3 inflammasome activation and cell apoptosis in microglia

There is no effective therapy for intracerebral hemorrhage (ICH) because of poor understanding of the mechanisms of brain injury after hemorrhage. The NLRP3 inflammasome, as a vital component of innate immune system, which is associated with a wide range of human CNS disorders, including ICH. But its detailed mechanisms in ICH remain mainly unclear. In this study, BV2 cells with thrombin exposure were used to investigate the role of NLRP3 inflammasome in thrombin-induced brain injury. We used western blot to detect NLRP3 inflammasome activation and the expression of thioredoxin binding protein (TXNIP), DCFH-DA to investigate intracellular reactive oxygen species (ROS), flow cytometry to analyze apoptosis. Our results showed that ROS inhibitor N-acetyl-l-cysteine (NAC) suppressed the upregulation of intracellular ROS and TXNIP expression. Furthermore, the cell apoptosis and expression of apoptotic protein were significantly attenuated after treatment of thrombin with NAC or NLRP3 antagonist (MCC950). Thrombin activates ROS/TXNIP/NLRP3 signaling in BV2 cells, which may indicate a mechanism that pro-inflammatory and pro-apoptotic contributes to the development of ICH.

Bone marrow stromal cells inhibits HMGB1-mediated inflammation after stroke in type 2 diabetic rats

High-mobility group box 1 (HMGB1), a ligand of receptor for advanced glycation endproducts (RAGE), functions as a proinflammatory factor. It is mainly involved in inflammatory activation and contributes to the initiation and progression of stroke. By using a model of transient middle cerebral artery occlusion (MCAo) in type 2 diabetic rats, we investigated the changes of pro-inflammation mediators, blood-brain barrier (BBB) leakage and functional outcome after stroke. Type 2 diabetic rats did not show an increased lesion volume, but exhibited significantly increased expression of HMGB1 and RAGE, BBB leakage, as well as decreased functional outcome after stroke compared with control rats. Injection of bone marrow stromal cells (BMSCs) into type 2 diabetic rats significantly reduced the expression of HMGB1 and RAGE, attenuated BBB leakage, and improved functional outcome after stroke. BMSCs-treated type 2 diabetic rats inhibited inflammation and improved functional outcome after stroke. Furthermore, in vitro data support the hypothesis that BMSCs-induced reduction of HMGB1 and RAGE in T2DM-MCAo rats contributed to attenuated inflammatory response in the ischemic brain, which may lead to the beneficial effects of BMSCs treatment. Further investigation of BMSCs treatment in type 2 diabetic stroke is warranted.

The protective role of (-)-epigallocatechin-3-gallate in thrombin-induced neuronal cell apoptosis and JNK-MAPK activation.

(−)-Epigallocatechin-3-gallate (EGCG), the major polyphenolic component of green tea, has anti-inflammatory and antioxidant properties and provides neuroprotection against central nervous system diseases. Yet, it is not known whether EGCG may be neuroprotective against intracerebral hemorrhage. In this study, we used a simplified in-vitro model of thrombin neurotoxicity to test whether EGCG provides neuroprotection against thrombin-associated toxicity. Exposure of primary cortical neurons to thrombin (100 U/ml) caused dose-dependent and time-dependent cytotoxicity. Cell Counting Kit 8 and lactate dehydrogenase were used to monitor cell viability after exposure of neurons to thrombin or EGCG and after EGCG pretreatment. Flow cytometric analysis and western blotting demonstrated that thrombin-induced neuron degeneration occurs through apoptosis. A concentration of 25 &mgr;M EGCG significantly abolished thrombin-induced toxicity and prevented apoptosis by suppressing c-Jun-N-terminal kinase (JNK) phosphorylation, and the JNK inhibitor SP600125 reduced thrombin-induced caspase 3 activation and apoptosis. These data suggest that EGCG may have protective effects against thrombin-induced neuroapoptosis by inhibiting the activation of JNK, leading to caspase 3 cleavage. EGCG is a novel candidate neuroprotective agent against intracerebral hemorrhage-induced neurotoxicity.

Dual effects of heme oxygenase-1 on astrocyte injury induced by hemin in vitro

Abstract Primary objective: The purpose of this study was to investigate the effects of heme oxygenase-1 (HO-1) on astrocyte injury induced by hemin. Research design: Primary astrocytes were isolated from Sprague Dawley rat pups and cultured in vitro. The expression of HO-1 was induced by hemin in a quantitative fashion and the effects of HO-1 on hemin-induced astrocyte injury were estimated by cell viability, cell membrane permeability and apoptosis. Methods and procedures: Astrocytes were divided into control group, hemin 5 μM group, hemin 5 μM + Zn-PPIX group, hemin 30 μM group and hemin 30 μM + Zn-PPIX group. Survival quality of astrocyte was measured by WST-8 assay, LDH assay, Hoechst 33258 Staining and annexin V-FITC/PI assay and apoptotic-related proteins were measured using Western blotting. Main outcome and results: Hemin could dose-dependently up-regulate the expression of HO-1. HO-1 exerted a protective role on astrocyte damage induced by 5 μM hemin, including increased cell survival rate and anti-apoptotic proteins expression (Bcl-2 and p-AKT), as well as decreased LDH release, apoptosis ratio and apoptotic protein expression (Bax, p-ERK and cleaved-caspase3). However, the effect of HO-1 on astrocyte injury between 30 μM hemin-treated groups was opposite of the protective role in 5 μM hemin-treated groups. Conclusions: There were dual effects of HO-1 in 5 μM and 30 μM hemin-induced astrocyte injuries.

Clinical and imaging characteristics of subacute combined degeneration complicated with white matter lesions in the brain: a report of five cases

Abstract Purpose: To report five cases of subacute combined degeneration (SCD) with brain involvement and explore its clinical and imaging characteristics. Methods: A retrospective study was performed on the clinical data and brain MRI of five patients with subacute combined degeneration with brain involvement (out of 107 cases with SCD in total). White matter lesions (WML) assessment was performed qualitatively using Fazekas scale score. Results: The main symptoms in four patients were weakness in both lower extremities and unstable walking (limb weakness in three patients, dizziness in three patients, and blurred vision in one patient). One patient had memory loss and cognitive dysfunction. The MMSE scale indicated mild dementia in one patient. On head MRI (Magnetic Resonance Imaging), multifocal and symmetrical high signals of T2WI and FLAIR were observed in the frontal lobe and periventricular white matter in four patients, while another patient showed preferential atrophy in frontal regions. Fazekas scale scores ranged from 1–6. Conclusion: Adult subacute combined degeneration seldom involves the brain. Multifocal and symmetrical high signal white matter lesions can be found on FLAIR and T2WI, as well as frontal atrophy on head MRI.

Thrombin-induced apoptosis in neurons through activation of c-Jun-N-terminal kinase.

Abstract Context: Studies have shown that thrombin activation played a central role in cell injuries associated with intracerebral hemorrhage (ICH). Objective: Here, our study investigated the cytotoxicity of thrombin on neurons, and determined the involvement of JNK pathways in thrombin-induced neuronal apoptosis. Materials and methods: Primary cultured neurons were treated with different doses of thrombin. Some neurons were given either SP600125 or vehicle. LDH release assay and flow cytometry were used to measure neuronal apoptosis caused by thrombin. The activation of JNK and capases-3 were measured by Western blot. Results: Our results showed large doses of thrombin that increased the LDH release, the level of cleaved caspase-3 and apoptosis rate of neurons. JNK was activated by thrombin in a time-dependent manner. Administration of SP600125 protects neurons from thrombin-induced apoptosis. Conclusion: These data indicate that the activation of JNK is crucial for thrombin-induced neuronal apoptosis, and inhibition of JNK may be a potential therapeutic target for ICH.

Superficial siderosis of central nervous system with unknown cause: report of 2 cases and review of the literature

Abstract Objective: To report 2 cases of superficial siderosis of central nervous system (SS-CNS) and a review of the literature. Methods: We have analyzed the clinical data and relevant features of two patients with SS-CNS who were presented with ataxia and slurred speech. Both patients undertook blood tests, lumbar puncture, head CT (computer tomography) scans, and brain and spinal cord magnetic resonance (MR) scans. In addition, the first patient also undewent enhanced susceptibility-weighted angiography (ESWAN) and the second patient undertook susceptibility weighted imaging (SWI) scan. We searched PubMed with the keywords superficial siderosis and superficial siderosis of central nervous system, and selected publications that seemed appropriate. Results: A neurological examination revealed bilateral sensorineural hearing impairment in both the patients. Their past history was not significant to identify hemorrhage. Brain MR scans demonstrated typical hypointensity rimming at the brain surface on T2 weighted images. The patients were diagnosed with SS-CNS. Conclusion: SS-CNS should be highly suspected in patients with progressive sensorineural hearing loss, ataxia, and signs of pyramidal tracts, and MR scans of brain and whole spinal cord should be undertaken to confirm the diagnosis. Advanced MRI techniques such as SWI and ESWAN are helpful in making the diagnosis of SS-CNS. The cause of hemorrhage is not identified in most cases.