Haiping Zhao

MicroRNA-23a-3p attenuates oxidative stress injury in a mouse model of focal cerebral ischemia-reperfusion.

The present study was designed to investigate the potential role of miR-23a-3p in experimental brain ischemia-reperfusion injury. Cerebral ischemia reperfusion was induced by transient middle cerebral artery occlusion (MCAO) for 1h in C57/BL6 mice. And miR-23a-3p angomir was transfected to upregulate the miR-23a-3p level. Our results showed that miR-23a-3p levels were transiently increased at 4h after reperfusion in the peri-infarction area, while markedly increased in the infarction core at reperfusion 4h and 24h. Importantly, in vivo study demonstrated that miR-23a-3p angomir treatment through intracerebroventricular injection markedly decreased cerebral infarction volume after MCAO. Simultaneously, miR-23a-3p reduced peroxidative production nitric oxide (NO) and 3-nitrotyrosine (3-NT), and increased the expression of manganese superoxide dismutase (MnSOD). In vitro study demonstrated that miR-23a-3p decreased hydrogen peroxide (H2O2)-induced lactate dehydrogenase (LDH) leakage dose-dependently, and reduced protein levels of activated caspase-3 in neuro-2a cells. In addition, miR-23a-3p reduced H2O2-induced production of NO and 3-NT dose-dependently, and reversed the decreased activity of total SOD and MnSOD in neuro-2a cells. Our study indicated that miR-23a-3p suppressed oxidative stress and lessened cerebral ischemia-reperfusion injury.

AKT/GSK3β-dependent autophagy contributes to the neuroprotection of limb remote ischemic postconditioning in the transient cerebral ischemic rat model.

Limb remote ischemic postconditioning (RIPostC) has been recognized as an applicable strategy in protecting against cerebral ischemic injury. However, the time window for application of limb RIPostC and the mechanisms behind RIPostC are still unclear.

Neuroprotective effect of microRNA-99a against focal cerebral ischemia-reperfusion injury in mice.

MicroRNA-99a (miR-99a) has been reported to function as a tumor suppressor through regulating cell cycle and apoptosis. But its clinical significance in ischemic stroke and its function in cerebral ischemia-reperfusion (I/R) injury remained unknown. Herein transient middle cerebral artery occlusion was built on C57BL/6 mice, followed by intracerebroventricular injection of miR-99a agomir or antagomir before reperfusion for 24h. Our clinical analysis indicates that plasma miR-99a level was significantly decreased in ischemic stroke patients as compared to healthy subjects, and a significant correlation was observed between miR-99a and clinical parameters. And miR-99a overexpression mitigated I/R injury in mice, as evidenced by reduced brain infarct volume and neural apoptosis, whereas miR-99a downregulation aggravates brain injury. In vitro, miR-99a protected neuro-2a cells against hydrogen peroxide-induced oxidative stress injury, by improving cell viability, suppressing LDH release and cell apoptosis. In addition, miR-99a overexpression inhibited H2O2 induced G1/S phase transition in neuro-2a cells, accompanied by a significant decrease in cyclin D1 level and a tendency of down-regulation of CDK6. It was further proved in mice that miR-99a inhibited cyclin D1 and CDK6 expressions following cerebral I/R injury. These findings indicate that miR-99a reduces neuronal damage following cerebral I/R through regulating cell cycle progression and preventing apoptosis, suggesting that miR-99a could be used as a new therapeutic agent targeting neuronal cell cycle re-entry following stroke.

MicroRNA-181c Exacerbates Brain Injury in Acute Ischemic Stroke

MicroRNA-181 (miR-181) is highly expressed in the brain, and downregulated in miRNA expression profiles of acute ischemic stroke patients. However, the roles of miR-181c in stroke are not known. The clinical relevance of miR-181c in acute stroke patients was evaluated by real-time PCR and correlation analyses. Proliferation and apoptosis of BV2 microglial cells and Neuro-2a cells cultured separately or together under oxidative stress or inflammation were assessed with the Cell Counting Kit-8 and by flow cytometry, respectively. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in C57/BL6 mice, and cerebral infarct volume, microglia activation, and expression of pro-apoptotic factors were evaluated by 2,3,5-triphenyl-2H-tetrazolium chloride staining, immunocytochemistry, and western blotting, respectively. Plasma levels of miR-181c were decreased in stroke patients relative to healthy individuals, and were positively correlated with neutrophil number and blood platelet count and negatively correlated with lymphocyte number. Lipopolysaccharide (LPS)/hydrogen peroxide (H2O2) treatment inhibited BV2 microglia proliferation without inducing apoptosis, while miR-181c reduced proliferation but increased the apoptosis of these cells with or without LPS/H2O2 treatment. LPS/H2O2 induced apoptosis in Neuro-2a cells co-cultured with BV2 cells, an effect that was potentiated by miR-181c. In the MCAO model, miR-181c agomir modestly increased infarct volume, markedly decreased microglia activation and B cell lymphoma-2 expression, and increased the levels of pro-apoptotic proteins in the ischemic brain. Our data indicate that miR-181c contributes to brain injury in acute ischemic stroke by promoting apoptosis of microglia and neurons via modulation of pro- and anti-apoptotic proteins.

Epigenetic Regulation of Oxidative Stress in Ischemic Stroke.

The prevalence and incidence of stroke rises with life expectancy. However, except for the use of recombinant tissue-type plasminogen activator, the translation of new therapies for acute stroke from animal models into humans has been relatively unsuccessful. Oxidative DNA and protein damage following stroke is typically associated with cell death. Cause-effect relationships between reactive oxygen species and epigenetic modifications have been established in aging, cancer, acute pancreatitis, and fatty liver disease. In addition, epigenetic regulatory mechanisms during stroke recovery have been reviewed, with focuses mainly on neural apoptosis, necrosis, and neuroplasticity. However, oxidative stress-induced epigenetic regulation in vascular neural networks following stroke has not been sufficiently explored. Improved understanding of the epigenetic regulatory network upon oxidative stress may provide effective antioxidant approaches for treating stroke. In this review, we summarize the epigenetic events, including DNA methylation, histone modification, and microRNAs, that result from oxidative stress following experimental stroke in animal and cell models, and the ways in which epigenetic changes and their crosstalk influence the redox state in neurons, glia, and vascular endothelial cells, helping us to understand the foregone and vicious epigenetic regulation of oxidative stress in the vascular neural network following stroke.

Improvement of hematoma absorption and neurological function in patients with acute intracerebral hemorrhage treated with Xueshuantong

Spontaneous intracerebral hemorrhage (ICH) leads to high mortality and morbidity. Currently, there is no effective therapy for ICH. Herein we conducted a clinical study in patients with acute ICH to investigate the efficacy of Xueshuantong Injection, a Chinese herbal prescription known for treatment of ischemic diseases in China. Patients (n=63) were randomly assigned to control (n=29) and Xueshuantong Injection treatment (175 mg/d, n=34) groups. Both groups were evaluated using their history and vital signs. The National Institutes of Health Stroke Scale (NIHSS) scores, hematoma volume by CT scanning, and inflammatory factors were assessed before and after two weeks treatment. There were no significant differences in all parameters between two groups before treatment. The treatment group showed significant decreases in both NIHSS score and hematoma volume, compared to control group after treatment (P<0.01 and P<0.05, respectively). Furthermore, the inflammatory factors, as measured by leukocytes, neutrophil percentage and C-reactive protein values, were significantly reduced in treatment group compared to control group after treatment (P<0.05, P<0.05, P<0.01 respectively). Our results showed that treatment with Xueshuantong Injection reduced inflammatory response and increased hematoma absorption, which significantly improved recovery of neurological function. This suggests Xueshuantong Injection as a potential treatment of patients with acute ICH.

Sex differences in health-related quality of life among adult stroke patients in Northeastern China.

Inconsistent results have been reported for the impact of sex on stroke outcomes. We investigated the differences in health-related quality of life between adult male and female stroke survivors in Northeastern China. Information on background variables was collected during hospital stay. Follow-up data were obtained through a phone interview 6 months after discharge, which included the Barthel Index and a 36-Item Short-Form Health Survey (SF-36) reflecting overall health status. The independent effects of sex on activities of daily living independence (Barthel Index ⩾ 95) were analyzed. Our results showed that female stroke patients were older than male stroke patients and were more likely to have transient ischemic attack and hypertension. Male stroke patients were more likely to have a history of smoking, heart disease and dyslipidemia, while female patients were less likely to achieve daily living independence. The mean scores of physical functioning, bodily pain, vitality, social functioning, emotional role, and mental health in the SF-36 survey were significantly higher in men than woman. Regression analyses confirmed that female sex was adversely associated with overall health status at discharge. In conclusion, our data demonstrated that there were sex differences in stroke recovery and quality of life among Chinese stroke survivors at 6 months post-discharge, with an overall worse stroke outcome for female stroke survivors.

Intra-artery infusion of recombinant human erythropoietin reduces blood-brain barrier disruption in rats following cerebral ischemia and reperfusion

Objectives: Intra-artery infusion of recombinant human erythropoietin (rhEPO) has recently been reported to confer neuroprotection against cerebral ischemia-reperfusion injury in animal models; however, the molecular mechanisms are still under investigation. The present study focused on the specific mechanism involved in blood–brain barrier (BBB) disruption. Methods: Thirty-six male and nine female Sprague Dawley rats were subjected to middle cerebral artery (MCA) occlusion to induce focal cerebral ischemia, and administrated rhEPO at a dose of 800 U/kg through MCA infusion at the beginning of reperfusion. Neurobehavioral deficits, brain edema, and infarct volume were evaluated after 2 h of ischemia and 24 h of reperfusion. BBB permeability was assessed by quantifying the extravasation of Evans blue (EB) dye. The expression of tight junction proteins and matrix metalloproteinases (MMPs) (Claudin-5, Occludin, MMP-2, and MMP-9) in microvessels were detected by immunofluorescence and western blot. The activities of MMPs in the cerebral microvessels were determined by gelatin zymography. Results: Treatment with rhEPO through the MCA strongly alleviated infarct volume, brain edema, and improved neurobehavioral outcomes in male and female rats. In addition, rhEPO remarkably suppressed the EB extravasation induced by brain ischemia. Furthermore, rhEPO prevented degradation of Claudin-5 and Occludin, and reduced the expression and activity of MMP-2 and MMP-9 in isolated brain microvessels. Conclusions: Treatment with rhEPO through MCA infusion prevented brain edema formation and infarction through inhibition of MMP-mediated BBB disruption in acute ischemic stroke.

Neuroprotective effects of Chrysophanol against inflammation in middle cerebral artery occlusion mice.

Ischemia/reperfusion (I/R) involves a cascade of reactions which ultimately lead to neuronal apoptosis or death. Inflammation plays an important role in this cascade. Chrysophanol (CHR), a purified active constituent from rhubarb, possesses many biological activities including anti-inflammation. The present study investigated the long-term neuroprotective effects of CHR on focal ischemic brain injury and the potential mechanism. Mice were subjected to 45-min middle cerebral artery occlusion and received either vehicle or CHR at 0.1, 1 or 10mg/kg for 14days after reperfusion. Neurological function, survival rate, brain tissue loss, expression of pro-inflammatory factors tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and nuclear factor-kappa B p65 (NF-κB p65) were then assessed. The results showed that treatment with CHR led to improved survival rate and reduced brain tissue loss compared with vehicle-treated mice, accompanied by improved neurological assessment and motor function, which were sustained for 14days after I/R. I/R-induced expression of TNF-α, IL-1β and NF-κB p65 in neurons was markedly reduced in CHR-treated mice. These results indicate that CHR markedly attenuates brain injury after focal I/R, which is attributed at least in part to its anti-inflammatory actions.

Peripheral to central: Organ interactions in stroke pathophysiology.

Stroke is associated with a high risk of disability and mortality, and with the exception of recombinant tissue-type plasminogen activator for acute stroke, most treatments have proven ineffective. Clinical translation of promising experimental therapeutics is limited by inadequate stroke models and a lack of understanding of the mechanisms underlying acute stroke and how they affect outcome. Bidirectional communication between the ischemic brain and peripheral immune system modulates stroke progression and tissue repair, while epidemiological studies have provided evidence of an association between organ dysfunction and stroke risk. This crosstalk can determine the fate of stroke patients and must be taken into consideration when investigating the pathophysiological mechanisms and therapeutic options for stroke. This review summarizes the current evidence for interactions between the brain and other organs in stroke pathophysiology in basic and clinic studies, and discusses the role of these interactions in the progression and outcome of stroke and how they can direct the development of more effective treatment strategies.