Animal Models Of Ischemic Stroke Research Articles

Role of Matrix Metalloproteinases in Animal Models of Ischemic Stroke

Matrix metalloproteinases (MMP) comprise a family of at least 25 zinc-dependent endopeptidases that play a pivotal role in the physiopathology of the mammalian central nervous system. In the first phases after stroke, the dysregulation of MMPs has been described to increase acute neurovascular disruption and cerebral injury. In particular, MMP-mediated alterations lead to blood-brain barrier (BBB) leakage, cerebral edema, hemorrhage, leukocyte infiltration and progressive inflammatory reactions underlying brain tissue loss. In addition, MMPs have been also shown to play critical activities during the repair phases of cerebral ischemia, particularly during angiogenesis and reestablishment of cerebral blood flow. The aim of this narrative review is to elucidate the mechanisms by which MMPs may provide detrimental and/or beneficial effects during the post-stroke injury and repair phases in animal models.

Abstract 712: Screening of Thrombolytic Agents in vivo Using a Novel Zebrafish Model of Ischemic Stroke Induced by Photochemical Thrombosis

Background: Timely thrombolytic therapy for acute ischemic stroke is important for improving neurological prognosis. Screening of thrombolytic agents on contemporary animal models of focal ischemic stroke is generally difficult as they require sophisticated surgical procedures such as induction of cerebral artery occlusion through mechanical ligation. Herein we seek to develop a novel zebrafish (Danio rerio) model of acute ischemic stroke for screening of thrombolytic drugs. Methods: All experiments were performed on a modified confocal optical microscope, which allows the induction of thrombosis at a selected blood vessel of larval zebrafish and the imaging of thrombotic and thrombolytic processes in real time. To initiate photochemical thrombosis, a 532-nm laser was focused at a blood vessel of a larva (4 dpf) that had been injected with a photosensitizer (rose bengal). To test the thrombolytic activity of tPA, we injected tPA to the blood vessel of a larval with a thrombus that partially occluded the blood flow. Results: Through photochemical means, we induced endothelial injury at selected blood vessel which subsequently triggered thrombosis. We show that an occlusion at the 1st branch of central artery drastically diminished the hemodynamics and cardiac function of larval zebrafish and impaired their capability to maintain balance during swimming whereas that at the basilar artery resulted in a high death rate. Immunofluorescent imaging shows that the photochemically induced thrombus comprised fibrins and platelets. After the injection of tPA to a larval with a partially occluded blood vessel, the fibrin mesh on the thrombus appeared sparse and limp which eventually led to the restoration of blood flow. Conclusions: Our zebrafish model of ischemic stroke is convenient to adapt and is highly reproducible. This model can potentially become an effective platform that benefits the screening of thrombolytic agents and the optimization of their dose.

Serum CXCL12 Levels as a Novel Predictor of Future Stroke Recurrence in Patients with Acute Ischemic Stroke.

Previous studies had shown that CXC chemokine ligand-12 (CXCL12) plays a significant role in animal models of ischemic stroke, but its role in human stroke is unclear. The aim of this study was to test the relationship between elevated serum circulating CXCL12 levels and the 1-year stroke recurrence in Chinese patients with acute ischemic stroke (AIS). All consecutive patients with first-ever acute ischemic stroke from January 2011 to September 2013 were recruited to participate in the study. Serum levels of CXCL12 and National Institute of Health Stroke Scale (NIHSS) were measured at the time of admission. Logistic regression analysis was used to evaluate the stroke recurrence according to serum CXCL12 levels. Receiver operating characteristic (ROC) curve was used to evaluate the accuracy of serum CXCL12 in predicting stroke recurrence. Clinical follow-up was performed at 1year. In our study, 248 patients finished the 1-year follow-up. At 1-year follow-up, 31 patients had a recurrence ischemic stroke. The median CXCL12 levels were significantly higher in those who sustained a recurrence ischemic stroke compared with those who did not [24.2ng/mL (IQR 15.4-33.7) vs 6.5ng/mL (IQR 3.4-10.2); Z = 8.258, P < 0.0001]. In multivariate analysis, there was an increased risk of stroke recurrence associated with serum CXCL12 levels ≥12.15ng/mL (OR 9.122, 95% CI 6.103-15.104) after adjusting for above possible confounders. The time to recurrence stroke distribution between patients with baseline CXCL12 levels ≥12.15ng/mL and those with baseline CXCL12 levels <12.15ng/mL were significantly different (P < 0.0001, log-rank test). Elevated circulating CXCL12 levels at admission are strongly associated with the future recurrence of ischemic stroke in Chinese patients with AIS. Further studies are warranted to confirm this association and define the role for CXCL12 as a novel predictor biomarker for stroke recurrence.

Effect of arginine vasopressin on the cortex edema in the ischemic stroke of Mongolian gerbils

Brain edema formation is one of the most important mechanisms of ischemia-evoked cerebral edema. It has been demonstrated that arginine vasopressin (AVP) receptors are involved in the pathophysiology of secondary brain damage after focal cerebral ischemia. In a well-characterized animal model of ischemic stroke of Mongolian gerbils, the present study was undertaken to clear the effect of AVP on cortex edema in cerebral ischemia. The results showed that (1) occluding the left carotid artery of Mongolian gerbils not only decreased the cortex specific gravity (cortex edema) but also increased AVP levels in the ipsilateral cortex (ischemic area) including left prefrontal lobe, left parietal lobe, left temporal lobe, left occipital lobe and left hippocampus for the first 6 hours, and did not change of the cortex specific gravity and AVP concentration in the right cortex (non-ischemic area); (2) there were many negative relationships between the specific gravity and AVP levels in the ischemic cortex; (3) intranasal AVP (50 ng or 200 ng), which could pass through the blood–brain barrier to the brain, aggravated the focal cortex edema, whereas intranasal AVP receptor antagonist-D(CH2)5Tyr(ET)DAVP (2 µg) mitigated the cortex edema in the ischemic area after occluding the left carotid artery of Mongolian gerbils; and (4) either intranasal AVP or AVP receptor antagonist did not evoke that edema in the non-ischemic cortex. The data indicated that AVP participated in the process of ischemia-evoked cortex edema, and the cerebral AVP receptor might serve as an important therapeutic target for the ischemia-evoked cortex edema.

Lasting Pure-Motor Deficits after Focal Posterior Internal Capsule White-Matter Infarcts in Rats

Small white-matter infarcts of the internal capsule are clinically prevalent but underrepresented among currently available animal models of ischemic stroke. In particular, the assessment of long-term outcome, a primary end point in clinical practice, has been challenging due to mild deficits and the rapid and often complete recovery in most experimental models. We, therefore, sought to develop a focal white-matter infarction model that can mimic the lasting neurologic deficits commonly observed in stroke patients. The potent vasoconstrictor endothelin-1 (n=24) or vehicle (n=9) was stereotactically injected into the internal capsule at one of three antero-posterior levels (1, 2, or 3 mm posterior to bregma) in male Sprague-Dawley rats. Endothelin-injected animals showed highly focal (~1 mm(3)) and reproducible ischemic infarcts, with severe axonal and myelin loss accompanied by cellular infiltration when examined 2 and 4 weeks after injection. Only those rats injected with endothelin-1 at the most posterior location developed robust and pure-motor deficits in adhesive removal, cylinder and foot-fault tests that persisted at 1 month, without detectable sensory impairments. In summary, we present an internal capsule stroke model optimized to produce lasting pure-motor deficits in rats that may be suitable to study neurologic recovery and rehabilitation after white-matter injury.

Active Compounds of Rhubarb Root and Rhizome in Animal Model Experiments of Focal Cerebral Ischemia.

Rhubarb root and rhizome (RRR) has been clinically used for stroke at least 2000 years and is still used in modern times in both China and elsewhere worldwide. The objective of present study was to evaluate the efficacy of active compounds of RRR (ACRRR) for experimental ischemic stroke. Studies of ACRRR in animal models of ischemic stroke were identified from 5 databases until April 2014. Study quality for each included article was evaluated according to the CAMARADES 10-item checklist. Outcome measures were neurological deficit score and infarct size. All the data were analyzed using RevMan 5.1 software. As a result, 20 studies were identified describing procedures involving 577 animals. The quality score of studies ranges from 2 to 6, and the median was 3.4. Six studies showed significant effects of ACRRR for improving infarct size compared with model group (P < 0.01). Six studies indicated significant effects of ACRRR for improving the neurological deficit scores according to Zea longa criterion or eight-point criterion (P < 0.01). In conclusion, these findings demonstrated a possible efficacy of ACRRR that have potential neuroprotective effect for experimental ischemic stroke. However, these apparently positive findings should be interpreted with caution because of the methodological flaws.

Empowering sonic hedgehog to rescue brain cells after ischemic stroke.

Ischemic stroke occurs when blood supply to the brain is interrupted. This can cause irreversible injury to the central nervous system (CNS) tissue. Each year in the United States almost 800,000 people experience a new or recurrent stroke. 15% of stroke patients die shortly after insult and only 10% recover completely, leaving the majority of surviving stroke patients with disabilities. Tissue-type plasminogen activator (tPA) is the only available therapy for stroke but its clinical use is limited because of associated danger of intracranial hemorrhage. Therefore, there is an emergent need for stroke therapeutics that are safe and effective when administered at a later time point after insult.

Neuroimmunomodulatory effects of transcranial laser therapy combined with intravenous tPA administration for acute cerebral ischemic injury

At present, the only FDA approved treatment for ischemic strokes is intravenous administration of tissue plasminogen activator within 4.5 hours of stroke onset. Owing to this brief window only a small percentage of patients receive tissue plasminogen activator. Transcranial laser therapy has been shown to be effective in animal models of acute ischemic stroke, resulting in significant improvement in neurological score and function. NEST-1 and NEST-2 clinical trials in human patients have demonstrated the safety and positive trends in efficacy of transcranial laser therapy for the treatment of ischemic stroke when initiated close to the time of stroke onset. Combining intravenous tissue plasminogen activator treatment with transcranial laser therapy may provide better functional outcomes. Statins given within 4 weeks of stroke onset improve stroke outcomes at 90 days compared to patients not given statins, and giving statins following transcranial laser therapy may provide an effective treatment for patients not able to be given tissue plasminogen activator due to time constraints.

Dodecafluoropentane emulsion delays and reduces MRI markers of infarction in a rat stroke model: a preliminary report

BackgroundDodecafluoropentane emulsion (DDFPe), an oxygen transport agent, has been shown to reduce infarct volume in animal models of acute ischemic stroke (AIS). Our study assesses the effect of DDFPe on MRI markers of infarct evolution in the early hours after vascular occlusion in a rat AIS model. We hypothesized that DDFPe will delay the development of MRI markers of AIS and/or reduce the extent of infarction. MethodsPermanent, unilateral surgical occlusion of the middle cerebral and common carotid arteries was performed in control (n=4) and treatment (n=10) rats. The treatment group received 1 IV dose of 2% w/v DDFPe at 0.6mL/kg at 1hour post-occlusion versus none. Diffusion-weighted (DWI) and inversion recovery (IR) MRI sequences were obtained over the 4hours following occlusion. Infarct extent was quantified by number of abnormal MRI slices per sequence for each group and time point. Student's T-test was applied. ResultsDDFPe-treated rats demonstrated reduced infarct extent versus controls over combined time points on IR at 5.43±0.40 (mean±standard error) abnormal slices vs. 7.38±0.58 (P=0.01) and on DWI at 5.21±0.54 vs. 9.00±0.95 (P<0.01). Development of abnormal MRI signal was delayed in the treatment group. ConclusionsDDFPe delays and reduces MRI markers of AIS in the early hours following vascular occlusion in a rat stroke model. Further investigation of DDFPe as a neuroprotectant is warranted.

IL-17A promotes myelin loss and inflammatory response during Cuprizone-induced demyelination

resident microglia (MG) and peripheral immune cells infiltrating into the region surrounding the infarct core and leading to secondary neurodegeneration. Current clinical therapies using thrombolytic and anti-platelet agents are limited by temporal restrictions and do not prevent the secondary, inflammation-related CNS damage. Therefore, the development of new anti-inflammatory therapies in ischemic stroke is necessary and urgent. Interferon beta (IFNbeta), a cytokine with immunomodulatory properties, was approved by the FDA for the treatment of relapsing–remitting multiple sclerosis for more than a decade. Its anti-inflammatory properties and well characterized safety profile suggest that IFNbeta has therapeutic potential for the treatment of ischemic stroke. We evaluated the therapeutic effect of IFNbeta treatment in the ischemic stroke animal model, murine transient middle cerebral artery occlusion/reperfusion (MCAO/R), as well as the regulatory effect of IFNbeta treatment on the infiltration of inflammatory peripheral immune cells into CNS infarcted region. Our results showed that IFNbeta treatment dramatically decreased infarct size in ischemic brains and that is correlated with significantly reduced neurological scores. In addition, the infiltration of inflammatory peripheral immune cells, including neutrophils and dendritic cells/macrophages, was also largely decreased in ischemic brains of IFNbeta-treated stroke mice, compared to those of control stroke mice. As MG activation and subsequent release of inflammatory cytokines in the ischemic brains exacerbate the disease of stroke, we compare MG activation and inflammatory cytokine expression in the ischemic brains of IFNbeta-treated and control stroke mice. We observed that IFNbeta treatment not only suppressed MG activation, but also inhibited inflammatory cytokine IL-1beta and MMP-9 expression in the ischemic brains. Taken altogether, our results demonstrate that IFNbeta confers a protective effect against ischemic stroke through its anti-inflammatory properties. (The study is supported by AHA grant 12SDG8170005 to JY.)

Efficacy of antidepressants in animal models of ischemic stroke: a systematic review and meta-analysis.

Poststroke depression is a prevalent complication of stroke with unclear pathogenesis. The benefits of antidepressants in this context and their effects on stroke recovery other than effects on mood are not clearly defined, with some studies suggesting efficacy in improving functional outcome in both depressed and nondepressed stroke patients. We have analyzed the preclinical animal data on antidepressant treatment in focal cerebral ischemia, modeled±depression, to help inform clinical trial design. We performed a systematic review and meta-analysis of data from experiments testing the efficacy of antidepressants versus no treatment to reduce infarct volume or improve neurobehavioral or neurogenesis outcomes in animal models of stroke. We used random-effects metaregression to test the impact of study quality and design characteristics and used trim and fill to assess publication bias. We identified 44 publications describing the effects of 22 antidepressant drugs. The median quality checklist score was 5 of a possible 10 (interquartile range, 4-7). Overall, antidepressants reduced infarct volume by 27.3% (95% confidence interval, 20.7%-33.8%) and improved neurobehavioral outcomes by 53.7% (46.4%-61.1%). There was little evidence for an effect of selective serotonin reuptake inhibitors on infarct volume. For neurobehavioral outcomes there was evidence of publication bias. Selective serotonin reuptake inhibitors were the most frequently studied antidepressant subtype and improved neurobehavioral outcome by 51.8% (38.6%-64.9%) and increased neurogenesis by 2.2 SD (1.3-3.0). In line with current clinical data and despite some limitations, antidepressant treatments seem to improve infarct volume and neurobehavioral outcome in animal models of ischemic stroke.

Effects of exogenous recombinant APC in mouse models of ischemia reperfusion injury and of atherosclerosis.

Activated protein C (APC) is a serine protease that has both anticoagulant and cytoprotective properties. The cytoprotective effects are protease activated receptor 1 (PAR-1) and endothelial protein C receptor (EPCR) dependent and likely underlie protective effects of APC in animal models of sepsis, myocardial infarction and ischemic stroke. S360A-(A)PC, a variant (A)PC that has no catalytic activity, binds EPCR and shifts pro-inflammatory signaling of the thrombin-PAR-1 complex to anti-inflammatory signaling. In this study we investigated effects of human (h)wt-PC, hS360A-PC, hwt-APC and hS360A-APC in acute (mouse model of acute myocardial ischemia/reperfusion (I/R) injury) and chronic inflammation (apoE−/− mouse model of atherosclerosis). All h(A)PC variants significantly reduced myocardial infarct area (p<0.05) following I/R injury. IL-6 levels in heart homogenates did not differ significantly between sham, placebo and treatment groups in I/R injury. None of the h(A)PC variants decreased number and size of atherosclerotic plaques in apoE−/− mice. Only hS360A-APC slightly affected phenotype of plaques. IL-6 levels in plasma were significantly (p<0.001) decreased in hwt-APC and hS360A-PC treated mice. In the last group levels of monocyte chemotactic protein 1 (MCP-1) were significantly increased (p<0.05). In this study we show that both hwt and hS360A-(A)PC protect against acute myocardial I/R injury, which implies that protection from I/R injury is independent of the proteolytic activity of APC. However, in the chronic atherosclerosis model hwt and hS360-(A)PC had only minor effects. When the dose, species and mode of (A)PC administration will be adjusted, we believe that (A)PC will have potential to influence development of chronic inflammation as occurring during atherosclerosis as well.

Protective mechanism of sulindac in an animal model of ischemic stroke

Background and PurposeThe present study analyzed whether administration of sulindac, a non-steroidal anti-inflammatory drug (NSAID) would prevent, attenuate or repair ischemia induced brain injury and reverse functional impairment in a focal ischemia model of stroke. MethodsMale Sprague-Dawley rats (weight 250–300g) were subjected to middle cerebral artery occlusion (MCAO). Sulindac was given 2 days before and 24h after ischemia at 0.2mg/day with daily injections until sacrifice on day 3 or day 11. Infarct size was measured by TTC staining and western immunoblot was employed. Results: TTC analysis of brain slices indicated a decrease in infarct size in sulindac treated animals. Western blot results indicated that sulindac induced expression of Hsp 27, a marker of cell stress, in the ischemic penumbra and core on days 3 and 11. Hsp 27 is important as a protective molecular chaperone. Increases were also found in the protective molecules Akt and Bcl-2 in the ischemic penumbra and core following sulindac administration. Conclusion: Our data indicate that administration of sulindac results in decreased infarct size and that there is a central role for the molecular chaperone Hsp 27, the pro-survival kinase Akt and the anti-apoptotic component Bcl-2 in mediating these protective effects.

Activation of Peroxisome Proliferator–activated Receptor β/δ Attenuates Acute Ischemic Stroke on Middle Cerebral Ischemia Occlusion in Rats

Peroxisome proliferator-activated receptor (PPAR)-β/δ is a transcription factor that belongs to the nuclear hormone receptor family. There is little information about the effects of the immediate administration of specific ligands of PPAR-β/δ (GW0742) in animal models of acute ischemic stroke. Using a rat model of middle cerebral ischemia occlusion (MCAO) invivo, we have investigated the effect of pretreatment with GW0742 before MCAO. The neuroprotective effect of GW0742 against acute ischemic stroke was evaluated by the neurologic deficit score (NDS), dry-wet weight, and 2,3,5-triphenyltetrazolium chloride staining. The levels of interleukin (IL)-1β, nuclear factor (NF)-κB, and tumor necrosis factor (TNF)-α were detected by an enzyme-linked immunosorbent assay. The expressions of inducible nitric oxide synthase (iNOS), Bax, and Bcl-2 were detected by Western blot. The apoptotic cells were counted by in situ terminal deoxyribonucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling assay. The pretreatment with GW0742 significantly increased the expression of Bcl-2, and significantly decreased in the volume of infarction, NDS, edema, expressions of IL-1β, NF-κB, TNFα, and Bax, contents of iNOS and the apoptotic cells in infarct cerebral hemisphere compared with rats in the vehicle group at 24hours after MCAO. The study suggests the neuroprotective effect of the PPAR-β/δ ligand GW0742 in acute ischemic stroke by a mechanism that may involve its anti-inflammatory and antiapoptotic action.

2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-d-pyranoside confers neuroprotection in cell and animal models of ischemic stroke through calpain1/PKA/CREB-mediated induction of neuronal glucose transporter 3

Salidroside is proven to be a neuroprotective agent of natural origin, and its analog, 2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-d-pyranoside (named SalA-4g), has been synthesized in our lab. In this study, we showed that SalA-4g promoted neuronal survival and inhibited neuronal apoptosis in primary hippocampal neurons exposed to oxygen and glucose deprivation (OGD) and in rats subjected to ischemia by transient middle cerebral artery occlusion (MCAO), respectively, and that SalA-4g was more neuroprotective than salidroside. We further found that SalA-4g elevated glucose uptake in OGD-injured primary hippocampal neurons and increased the expression and recruitment of glucose transporter 3 (GLUT3) in ischemic brain. Signaling analysis revealed that SalA-4g triggered the phosphorylation of CREB, and increased the expression of PKA RII in primary hippocampal neurons exposed to OGD injury, while inhibition of PKA/CREB by H-89 alleviated the elevation in glucose uptake and GLUT3 expression, and blocked the protective effects of SalA-4g. Moreover, SalA-4g was noted to inhibit intracellular Ca2+ influx and calpain1 activation in OGD-injured primary hippocampal neurons. Our results suggest that SalA-4g neuroprotection might be mediated by increased glucose uptake and elevated GLUT3 expression through calpain1/PKA/CREB pathway.

Brain to blood glutamate scavenging as a novel therapeutic modality: a review

It is well known that abnormally elevated glutamate levels in the brain are associated with secondary brain injury following acute and chronic brain insults. As such, a tight regulation of brain glutamate concentrations is of utmost importance in preventing the neurodegenerative effects of excess glutamate. There has been much effort in recent years to better understand the mechanisms by which glutamate is reduced in the brain to non-toxic concentrations, and in how to safely accelerate these mechanisms. Blood glutamate scavengers such as oxaloacetate, pyruvate, glutamate-oxaloacetate transaminase, and glutamate-pyruvate transaminase have been shown to reduce blood glutamate concentrations, thereby increasing the driving force of the brain to blood glutamate efflux and subsequently reducing brain glutamate levels. In the past decade, blood glutamate scavengers have gained increasing international interest, and its uses have been applied to a wide range of experimental contexts in animal models of traumatic brain injury, ischemic stroke, subarachnoid hemorrhage, epilepsy, migraine, and malignant gliomas. Although glutamate scavengers have not yet been used in humans, there is increasing evidence that their use may provide effective and exciting new therapeutic modalities. Here, we review the laboratory evidence for the use of blood glutamate scavengers. Other experimental neuroprotective treatments thought to scavenge blood glutamate, including estrogen and progesterone, beta-adrenergic activation, hypothermia, insulin and glucagon, and hemodialysis and peritoneal dialysis are also discussed. The evidence reviewed here will hopefully pave the way for future clinical trials.

Exercise Reduces Infarct Volume and Facilitates Neurobehavioral Recovery

Background. Regular exercise reduces the risk of a first-ever stroke and is associated with smaller infarcts. Although evidence has suggested that therapeutic exercise following stroke is beneficial, we do not yet know whether exercise reduces stroke severity and improves functional recovery. The mechanisms underlying any benefit remain unclear. Objective. To conduct a systematic review and meta-analysis of studies testing exercise in animal models of ischemic stroke where outcomes were measured as infarct volume, neurobehavioral score, neurogenesis, or a combination of these. We also sought evidence of publication bias. Methods. We searched 3 online databases for publications reporting the use of exercise in focal cerebral ischemia. We used DerSimonian and Laird normalized random-effects meta-analysis and meta-regression to determine the impact of study quality and design on the efficacy of exercise. Results. Overall, exercise reduced infarct volume by 25.2% (95% confidence interval [CI] = 19.0%-31.3%; 65 experiments and 986 animals) and improved neurobehavioral score by 38.2% (95% CI = 29.1%-47.3%; 42 experiments; n = 771). For both outcomes, larger effects were seen when exercise preceded ischemia rather than came after it. For neurobehavioral scores, we found evidence of publication bias. Reported study quality was moderate (median score 5/10). Both model-specific (eg, type of ischemia) and exercise-specific characteristics influenced reported outcome. Conclusion. Exercise, either before or after ischemia, reduced infarct volume and improved neurobehavioral score. However, overall estimates of efficacy were higher in studies at risk of bias, and for neurobehavioral outcomes, there was evidence of a substantial publication bias.

Abstract 196: Human Recombinant Peptide (RCP) Sponge Enables Novel Noninvasive Cell Therapy for Ischemic Stroke

Background: The bone marrow stromal cells (BMSCs) have the potential to improve neurologic function when transplanted into animal models of ischemic stroke. However, it is unclear through which route the BMSC should be delivered to yield the maximal therapeutic benefits safely. Using genetic engineering technique, the authors have developed the recombinant peptide (RCP) sponge of human collagen. Therefore, this study was aimed to assess whether the RCP sponge of human collagen could act as a noninvasive, valuable scaffold in cell therapy for ischemic stroke. Methods: The BMSCs were harvested from GFP-transgenic rats and were cultured in the RCP sponge. The rats were subjected to permanent middle cerebral artery (MCA) occlusion. Vehicle, BMSC suspension, or the BMSC-RCP sponge construct was transplanted onto the ipsilateral intact neocortex at 7 days after the insult. Motor function was serially evaluated throughout the experiments. The distribution and fate of engrafted cells were examined at 6 weeks after BMSC transplantation. Results: The BMSCs proliferated in the RCP sponge in vitro. Transplantation of BMSC suspension or the BMSC-RCP sponge construct equally promoted functional recovery, when compared with the vehicle group. RCP sponge provoked no inflammatory reactions in the host brain. Histological analysis revealed that the BMSC migrated and differentiated into the neural cells in the infarct brain when transplanted using the RCP sponge. Conclusion: These findings suggest that surgical transplantation of tissue-engineered BMSC onto the infarct neocortex may enhance functional recovery. RCP sponge can be a promising candidate for the animal protein-free scaffolds in cell therapy for ischemic stroke.

Recovery of neurological function of ischemic stroke by application of conditioned medium of bone marrow mesenchymal stem cells derived from normal and cerebral ischemia rats

BackgroundSeveral lines of evidence have demonstrated that bone marrow-derived mesenchymal stem cells (BM-MSC) release bioactive factors and provide neuroprotection for CNS injury. However, it remains elusive whether BM-MSC derived from healthy donors or stroke patients provides equal therapeutic potential. The present work aims to characterize BM-MSC prepared from normal healthy rats (NormBM-MSC) and cerebral ischemia rats (IschBM-MSC), and examine the effects of their conditioned medium (Cm) on ischemic stroke animal model.ResultsIsolated NormBM-MSC or IschBM-MSC formed fibroblastic like morphology and expressed CD29, CD90 and CD44 but failed to express the hematopoietic marker CD34. The number of colony formation of BM-MSC was more abundant in IschBM-MSC than in NormBM-MSC. This is in contrast to the amount of Ficoll-fractionated mononuclear cells from normal donor and ischemic rats. The effect of cm of BM-MSC was further examined in cultures and in middle cerebral artery occlusion (MCAo) animal model. Both NormBM-MSC Cm and IschBM-MSC Cm effectively increased neuronal connection and survival in mixed neuron-glial cultures. In vivo, intravenous infusion of NormBM-MSC Cm and IschBM-MSC Cm after stroke onset remarkably improved functional recovery. Furthermore, NormBM-MSC Cm and IschBM-MSC Cm increased neurogenesis and attenuated microglia/ macrophage infiltration in MCAo rat brains.ConclusionsOur data suggest equal effectiveness of BM-MSC Cm derived from ischemic animals or from a normal population. Our results thus revealed the potential of BM-MSC Cm on treatment of ischemic stroke.

The significance of matrix metalloproteinase (MMP)-2 and MMP-9 in the ischemic stroke

There is a continuous urgent need to explore the pathogenesis and biochemical changes within the infarcted area during acute ischemic stroke (IS). Matrix metalloproteinases (MMPs), prevailing extracellular endopeptideses, can digest proteins located extracellulary, e.g. collagen, proteoglycans, elastin or fibronectin. Among MMPs, gelatinases (MMP-2 and MMP-9) are the most investigated enzymes. Gelatinases possess the ability to active numerous pro-inflammatory agents as chemokine CXCL-8, interleukin 1β or tumor necrosis factor α. Moreover, due to digestion of collagen type IV (the component of basal membranes) and tight junction proteins (TJPs) they facilitate to cross the endothelium by leukocytes. Due to the significant role of gelatinases during brain ischemia, their selective inhibition seems to be an interesting kind of treatment of acute stroke. The synthetic inhibitors of gelatineses decrease the infarct volume in animal models of IS. In clinical practice statins, the lipid-lowering drugs possess the ability to inhibit the activity of MMP-9 during acute IS. This review briefly provides the most important information about the involvement of MMP-2 and MMP-9 in the pathogenesis of brain ischemia.