Acute Cerebral Ischemia-reperfusion Research Articles

Effect of Xiaoxuming Decoction on synaptic plasticity following acute cerebral ischemia-reperfusion in rats

This study aims to explore the effect of Xiaoxuming Decoction on synaptic plasticity in rats with acute cerebral ischemia-reperfusion. A rat model of cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion(MCAO). Rats were randomly assigned into a sham group, a MCAO group, and a Xiaoxuming Decoction(60 g·kg~(-1)·d~(-1)) group. The Longa score was rated to assess the neurological function of rats with cerebral ischemia for 1.5 h and reperfusion for 24 h. The 2,3,5-triphenyltetrazolium chloride(TTC) staining and hematoxylin-eosin(HE) staining were employed to observe the cerebral infarction and the pathological changes of brain tissue after cerebral ischemia, respectively. Transmission electron microscopy was employed to detect the structural changes of neurons and synapses in the ischemic penumbra, and immunofluorescence, Western blot to determine the expression of synaptophysin(SYN), neuronal nuclei(NEUN), and postsynaptic density 95(PSD95) in the ischemic penumbra. The experimental results showed that the modeling increased the Longa score and led to cerebral infarction after 24 h of ischemia-reperfusion. Compared with the model group, Xiaoxuming Decoction intervention significantly decreased the Longa score and reduced the formation of cerebral infarction area. The modeling led to the shrinking and vacuolar changes of nuclei in the brain tissue, disordered cell arrangement, and severe cortical ischemia-reperfusion injury, while the pathological damage in the Xiaoxuming Decoction group was mild. The modeling blurred the synaptic boundaries and broadened the synaptic gap, while such changes were recovered in the Xiaoxuming Decoction group. The modeling decreased the fluorescence intensity of NEUN and SYN, while the intensity in Xiaoxuming Decoction group was significantly higher than that in the model group. The expression of SYN and PSD95 in the ischemic penumbra was down-regulated in the model group, while such down-regulation can be alleviated by Xiaoxuming Decoction. In summary, Xiaoxuming Decoction may improve the synaptic plasticity of ischemic penumbra during acute cerebral ischemia-reperfusion by up-regulating the expression of SYN and PSD95.

Mailuoning oral liquid attenuates convalescent cerebral ischemia by inhibiting AMPK/mTOR-associated apoptosis and promoting CREB/BDNF-mediated neuroprotection

Ethnopharmacological relevanceIschemic stroke is divided into acute, subacute and convalescent phases according to the time of onset. Clinically, Mailuoning oral liquid (MLN O) is a traditional Chinese patent medicine for treating ischemic stroke. Previous studies have shown that MLN O could prevent acute cerebral ischemia-reperfusion. However, its underlying mechanism remains unclear. Aim of the studyTo investigate the relationship between neuroprotection and apoptosis for clarifying MLN O mechanism in the recovery phase of ischemic stroke. Materials and methodsWe imitated stroke using middle cerebral artery occlusion/reperfusion (MCAO/R) in vivo and oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro models. The infarct volume, neurological deficit scores, HE staining, Nissl staining, TUNEL staining, immunohistochemistry, and Western blot were correspondingly performed to find pathological changes and detect neuronal apoptosis in rat cerebral cortex. The contents of LDH, Cyt-c, c-AMP and BDNF in rat plasma and cerebral cortex were detected by ELISA. Cell viability was measured by CCK8 assay. Cell morphology, Hoechst 33342 staining and Annexin-V-Alexa Fluor 647/PI staining were performed to assess neuronal apoptosis. The expression levels of proteins were evaluated by western blotting. ResultsMLN O obviously reduced brain infarct volume and neurological deficit scores in MCAO rats. MLN O inhibited inflammatory cell infiltration and neuronal apoptosis, but promoted gliosis, neuronal survival, and neuroprotection in the cortical region of MCAO rats. Additionally, MLN O decreased the amount of LDH and cytochrome c, while increasing the expression of c-AMP in the plasma and ischemic cerebral cortex of MCAO rats, and promoting the expression of BDNF in the cortical tissue of MCAO rats. Besides, MLN O improved cell viability, restored cell morphology, while attenuating cell damage, inhibiting neuronal apoptosis following OGD/R in PC-12 cells. Moreover, MLN O inhibited apoptosis by suppressing the expression of pro-apoptotic-associated proteins, including Bax, cytochrome c, Cleaved caspase 3 and HIF-1α, whereas accelerating the expression of Bcl-2 in vivo and in vitro. Furthermore, MLN O inhibited the activity of AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR), but activated the signaling pathway of cAMP-response element binding protein (CREB)/brain-derived neurotrophic factor (BDNF) in MCAO rats and OGD/R-stimulated PC-12 cells. ConclusionsThese results demonstrated that MLN O inhibited AMPK/mTOR to affect apoptosis associated with mitochondria, leading to improve CREB/BDNF-mediated neuroprotection in the recovery period of ischemic stroke in vivo and in vitro.

Protective effect and underlying mechanism of muscone on acute cerebral ischemia-reperfusion injury in rats.

Musk is a widely used traditional Chinese medicine, which has resuscitation, activating blood, and disperse swelling effects. Musk is commonly used in the prevention of myocardial infarction and ischemic stroke, and muscone is its main active component. The effect and mechanism of muscone to improve the condition of ischemic stroke is not clear, accordingly, we verified its efficacy in ischemia-reperfused rats, and investigated its mechanism by PC12 and THP-1cells. A transient middle cerebral artery occlusion (tMCAO) rat model was established for in vivo experiments. 2,3,5-Triphenyl Tetrazolium Chloride (TTC) staining was used to calculate infarct rate. Neuroprotection and angiogenesis were assessed by Hematoxylin-eosin (HE) staining, nissl staining, immunofluorescence staining, and quantitative real-time PCR (qRT-PCR). Oxygen glucose deprivation-reperfusion (OGD/R) model of PC12cells was established for neuroprotection analysis, where CCK-8 assay was used to measure cell viability, flow cytometry and Hoechst 33258 staining were used to demonstrate apoptosis, and protein levels were detected by Western blot. For angiogenesis analysis, enzyme-linked immunosorbent assay (ELISA) and qRT-PCR were used to detect angiogenic factors expressed by THP-1. Cell viability assay, scratch wound assay, and tube formation assay were used to evaluate angiogenic effect of HUVECs treated with medium of THP-1. And the angiogenic pathway in HUVECs was detected by Western blot. According to the results, in cerebral ischemia-reperfusion rats, the infarct rate and tissue damage were significantly reduced by muscone, and the expression of neurotrophic factors and angiogenesis-related factors were all elevated. In OGD/R-PC12cell models, muscone could increase cell viability and inhibit apoptosis via Bax/Bcl-2/Caspase-3 pathway. In THP-1-mediated angiogenesis of HUVECs, muscone promoted the secretion of angiogenesis-related factors in THP-1 and thus indirectly promoted the proliferation, migration and tube formation of HUVECs, and then regulated phosphorylation of VEGFR2 and Akt in HUVECs. Our study indicated that muscone may be a potential neuroprotective and proangiogenic agent in cerebral ischemia.

Pre exposure to enriched environment alleviates brain injury after ischemia-reperfusion by inhibiting p38MAPK/STAT1 pathway

BackgroundStroke is one of the major diseases that endangers human health. It is widely reported that enriched environment (EE) can improve the neurological function in different brain injury models. Recently, relevant researches have indicated that MAPK pathway is closely related to the inflammatory response in nervous system related diseases. However, whether pre exposure to EE (EE pretreatment) has a preventive effect, and its mechanism are not clear. Therefore, this study aimed to determine the possible benefits and related mechanisms of EE in preventing brain injury after acute ischemia-reperfusion.MethodsAdult Sprague Dawley rats were kept in enriched or standardized environments for 21 days. Then the middle cerebral artery of rats was occluded for one hour and 30 min, and then reperfusion was performed. Then their neurological deficit score was evaluated. Cerebral edema, along with ELISA and protein quantities of p38MAPK, JNK, ERK, IL-1β, TNF-α, and co-localization of Iba1 were assessed. Changes in neuroinflammation and apoptosis were also detected in the penumbra cortex.ResultsOur research showed that EE pretreatment significantly alleviated acute cerebral ischemia-reperfusion injury in rats. Including the reduction of brain edema and apoptosis, and the improvement of neurological scores. In addition, the protein level of p38MAPK was significantly down regulated in EE pretreatment group, and the downstream protein STAT1 had the same trend. In addition, immunofluorescence results showed that Iba1 in EE pretreatment group decreased, the ELISA results showed that the classical proinflammatory cytokines increased significantly, while anti-inflammatory cytokines in EE pretreatment group increased, and the same results were obtained by Western blot analysis.ConclusionOn the whole, our research demonstrated that EE pretreatment can have a protective effect on the organism by inhibiting the p38 MAPK/STAT1 pathway. Thus, EE can be one of the most promising means of disease prevention. Secondly, p38MAPK/STAT1 pathway may be a latent target for the prevention of acute ischemic stroke.

TJ-M2010-5, a novel CNS drug candidate, attenuates acute cerebral ischemia-reperfusion injury through the MyD88/NF-κB and ERK pathway.

Background: Cerebral ischemia-reperfusion injury (CIRI) inevitably occurs after vascular recanalization treatment for ischemic stroke. The accompanying inflammatory cascades have a major impact on outcome and regeneration after ischemic stroke. Evidences have demonstrated that TLR/MyD88/NF-κB signaling contributes to CIRI. This study aimed to investigate the druggability of MyD88 in the central nervous system (CNS) and the neuroprotective and anti-neuroinflammatory effects of the MyD88 inhibitor TJ-M2010-5 on CIRI. Methods: A middle cerebral artery occlusion (MCAO) model was used to simulate CIRI in mice. BV-2 cells were stimulated with oxygen glucose deprivation/reoxygenation (OGD/R) or lipopolysaccharide, and SH-SY5Y cells were induced by OGD/R in vitro. Neurological deficit scores and cerebral infarction volumes were evaluated. Immunofluorescence staining was performed to measure neuronal damage and apoptosis in the brain. The anti-neuroinflammatory effect of TJ-M2010-5 was evaluated by analyzing the expression of inflammatory cytokines, activation of microglia, and infiltration of peripheral myeloid cells. The expression of proteins of the MyD88/NF-κB and ERK pathway was detected by Simple Western. The concentrations of TJ-M2010-5 in the blood and brain were analyzed by liquid chromatography-mass spectrometry. Results: The cerebral infarction volume decreased in mice treated with TJ-M2010-5, with the most prominent decrease being approximately 80% of the original infarction volume. Neuronal loss and apoptosis were reduced following TJ-M2010-5 treatment. TJ-M2010-5 inhibited the infiltration of peripheral myeloid cells and the activation of microglia. TJ-M2010-5 also downregulated the expression of inflammatory cytokines and inhibited the MyD88/NF-κB and ERK pathway. Furthermore, TJ-M2010-5 showed good blood-brain barrier permeability and no neurotoxicity. Conclusion: TJ-M2010-5 has an excellent therapeutic effect on CIRI as a novel CNS drug candidate by inhibiting excessive neuroinflammatory responses.

Eye acupuncture improves cerebral ischemia reperfusion injury by improving autophagy via ATF6 pathway in cerebral ischemia reperfusion injury rats

To explore the effect of eye acupuncture on autophagy and expressions of autophagy-related proteins Beclin1, LC3B, ATF6 and XBP1 in the infarction area of brain tissue in rats with acute cerebral ischemia-reperfusion injury (CIRI), so as to explore its mechanisms underlying improvement of CIRI. Male SD rats were randomly divided into sham operation, model and eye acupuncture groups (n=16 in each group). The CIRI model was prepared by occlusion of the middle cerebral artery. Eye acupuncture stimulation was applied to bilateral "Gan"(Liver), "Shangjiao"(Upper-energizer), "Xiajiao"(Lower-energizer) and "Shen"(Kidney) regions at 0, 12 and 24 h after CIRI, 30 min each time. The neurological deficit score was given by referring to Longa's method, and TTC staining used to determine the success of model replication. After the treatment, the pathological changes of the cerebral infarction area were observed under light microscope, and the autophagosomes were observed by electron microscope. The protein expression levels of LC3B, Beclin1, ATF6 and XBP1 in the infarction area of brain tissue were detected by Western blot. The immunoactivity of Beclin1 and the immunofluorescence density of ATF6 and XBP1 in the infarction area of brain tissue were determined by immunohistochemistry. The Longa's score, and the protein expression levels of LC3B, Beclin1, ATF6 and XBP1 and immunoactivity or immunofluorescence density of Beclin1, ATF6 and XBP1 were significantly higher in the model group than those in the sham operation group (P<0.01), and considerably lower in the eye acupuncture group than those in the model group (P<0.01). Under light microscope, the model group had typical ethmoidal reticular cerebral infarction, while the eye acupuncture group had significantly smaller areas and clearer edges. Under electron microscope, there were more autophagosomes in the cytoplasm of neurons in the model group, and fewer autophagosomes in the eye acupuncture group (in contrast to the model group). Eye acupuncture can improve the neurological function and mitigate cerebral injury in CIRI rats which may be associated with its function in inhibiting autophagy in the brain tissue by regulating ATF6 pathway.

The effect of mesenchymal stromal cells of various origins on mortality and neurologic deficit in acute ischemia-reperfusion in rats

Stroke is a global epidemic issue and the second leading cause of death in the world and in Ukraine. According to official statistics, every year 100-110 thousand Ukrainians suffer acute cerebrovascular disorders. One third of such patients are of working age, up to 50 % will have a disability, and only one in ten will fully return to full life. So far, promising experimental data on the treatment of neurological dysfunction using mesenchymal stromal cells (MSCs) have been obtained. The aim of study is to compare the effect of MSCs of different origins on mortality and neurologic deficit in rats with acute cerebral ischemia-reperfusion injury (CIRI). Materials and methods. Transient bilateral 20-minute occlusion of internal carotid arteries was modeled in male Wistar rats aged 4 months and animals were injected intravenously with MSCs derived from human umbilical cord Wharton's-jelly (hWJ-MSC), human and rat adipose tissue. Other groups of experimental animals were injected intravenously with rat fetal fibroblasts and cell lysate from hWJ-MSC. The last group of rats received Citicoline at a dose of 250 mg/kg as a reference drug. Control animals were injected intravenously with normal saline. The cerebroprotective effect of therapy was assessed by mortality and neurologic deficit in rats on the McGraw's stroke index score. Results. After 12 hours of observation in the crucial period in the development of experimental acute cerebrovascular disorders with the administration of hWJ-MSC, mortality was only 10 % against 45 % of animals in the control group. The use of rat fetal fibroblasts reduced the mortality of animals compare to the control group by an average of 25 %. CIRI in rats caused severe neurologic deficits: paralysis, paresis, ptosis, circling behavior. On the 7th day of observation in the control group of animals, the mean score on the McGrow's stroke index indicated severe neurological disorders. On the 14th day of observation in this group of animals there was no complete recovery of lost central nervous system functions. Compared with the control group of animals, all the treatment agents for acute CIRI (MSCs of various origins, MSC's lysate and Citicoline) contributed to a significant regression of neurologic deficit. Conclusions. Thus, transplantation of human Wharton's jelly-derived MSCs and rat fetal fibroblasts reduced mortality and alleviated neurological symptoms in rats with experimental ischemic stroke. hWJ-MSC, rat fetal fibroblasts, and rat adipose-derived MSCs reduced the incidence of neurological disorders better than Citicoline, which was accompanied by a regression of neurologic deficit dynamics on the 14th day of follow-up. The ability of stem cells of different origins to reduce neurologic deficit indicates the feasibility of their use in experimental acute cerebral ischemia.

Panax Notoginseng Protects against Diabetes-Associated Endothelial Dysfunction: Comparison between Ethanolic Extract and Total Saponin.

Previous studies revealed a cardioprotective potential of Panax notoginseng to relieve acute myocardial infarction and focal cerebral ischemia-reperfusion. However, whether P. notoginseng protects endothelial function in diabetes and the underlying mechanisms remain to be explored. P. notoginseng contains several chemical components including saponins, which are commonly believed as the major bioactive ingredients. The present study was aimed to examine and compare the vaso-protective effects of the ethanolic extract of P. notoginseng (PNE) and total saponin (PNS). Both aortas and carotid arteries were isolated from male C57BL/6J mice for ex vivo treatment with risk factors (high glucose or tunicamycin) with and without the presence of PNS and PNE. Diabetic model was established by feeding the mice with a high-fat diet (45% kcal% fat) for 12 weeks, while PNS and PNE were administrated by oral gavage at 20 mg/kg/day for another 4 weeks. Ex vivo exposure to high glucose impaired acetylcholine-induced endothelium-dependent relaxations in mouse aortas, decreased phosphorylation of AMPK and eNOS, and induced endoplasmic reticulum (ER) stress and oxidative stress. These effects were reversed by cotreatment of PNS and PNE with PNS being more potent. Furthermore, the vaso-protective effects were abolished by Compound C (AMPK inhibitor). Chronic treatment with PNS and PNE improved endothelium-dependent relaxations and alleviated ER stress and oxidative stress in aortas from high-fat diet-induced obese mice. PNE was more effective to improve glucose sensitivity and normalize blood pressure in diabetic mice. The present results showed that PNS and PNE reduced ER stress and oxidative stress and, subsequently, improved endothelial function in diabetes through AMPK activation. This study provides new inspiration on the therapeutic potential of P. notoginseng extract against vascular diseases associated with metabolic disorders.

Salvianolic acid A alleviated inflammatory response mediated by microglia through inhibiting the activation of TLR2/4 in acute cerebral ischemia-reperfusion

BackgroundToll-like receptor 2 and Toll-like receptor 4 (TLR2/4) on microglia have been found as important regulators in the inflammatory response during cerebral ischemia/reperfusion (I/R). In China, traditional Chinese medicine Salvia miltiorrhiza (danshen) and its some components are considered to be effective in rescuing cerebral I/R injury through clinical practice. Hypothesis/PurposeHere we examined the effect of Salvianolic acid A (SAA), a monomer compound in the water extract of Salvia miltiorrhiza, on TLR2/4 of microglia and its mediated inflammatory injury during cerebral I/R in vivo and in vitro. Study DesignFor exploring the effect of SAA on cerebral I/R and TLR2/4, classic middle cerebral artery occlusion (MCAO) model and oxygen glucose deprivation / reoxygenation (OGD/R) model of co-culture with primary hippocampal neurons and microglia in vitro were used. Signal pathway research and gene knockout have been applied to further explain its mechanism. MethodsThe evaluation indexes of I/R injury included infarct size, edema degree and pathology as well as primary hippocampal neurons and microglia culture, ELISA, western, RT-PCR, HE staining, immunofluorescence, flow cytometry, siRNA gene knockout were also employed. ResultsSAA significantly improved the degree of brain edema and ischemic area in I/R rats accompanied by decreases in levels of interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). Pathological staining revealed that SAA could reduce inflammatory cell infiltration and mcirogila activation after reperfusion. Both protein and gene expression of TLR2 and TLR4 in ischemic hemisphere were obviously inhibited by SAA treatment while changes were not found in the non-ischemic hemisphere. In order to further study its mechanism, OGD/R model was used to mimic inflammatory damage of ischemic tissue by co-culturing primary rat hippocampal neurons and microglial cells. It was found that SAA also inhibited the protein and gene expression of TLR2 and TLR4 after OGD/R injury in microglia. After TLR2/4 knockout, the inhibitory effect of SAA on IL-1β and TNF-α levels in cell supernatant and neuron apoptosis were significantly weakened in each dose group. Moreover, expression levels of myeloid differentiation factor 88 (MyD88), NFκB, IL-1β and IL-6 in TLR2/4 mediated inflammatory pathway were reduced with SAA treatment. ConclusionSAA could significantly reduce the inflammatory response and injury in cerebral ischemia-reperfusion in vivo and in vitro, and its mechanism may be through the inhibition of TLR2/4 and its related signal pathway.

Analysis of regulatory effect of miR-149-5p on Sphingosine-1-phosphate receptor 2 of pericytes and its neuroprotective molecular mechanism after acute cerebral ischemia reperfusion in rats

ABSTRACT To investigate the effect of miR-149-5p on sphingosine-1-phosphate receptor 2 (S1PR2) expression level and contents of matrix metalloproteinase (MMP-9) and superoxide dismutase (SOD) in the pericytes after acute cerebral ischemia reperfusion in rats, so as to clarify the neuroprotective molecular mechanism induced by miR-149-5p and provide references for the treatment of neurological diseases, 60 male SD rats aged 7–8 weeks were selected and divided randomly into test group (establishing middle cerebral artery occlusion (MCAO) model) and control group (no modeling). Rat pericytes and peripheral cerebral infarction tissues were collected 12 h, 1 d, 3 d, 5 d, and 7 d after MCAO modeling, respectively. The pericytes were identified by immunofluorescence assay (IFA) and transfected with miR-149-5p. Fluorescence quantitative PCR (FQPCR) and Western blot were adopted to detect S1PR2 expression level. The expression of S1PR2 in MCAO model rats was detected by IFA. Immunohistochemistry (IHC) and quantitative real-time PCR (qRT-PCR) were used to detect the changes of MMP9 protein and mRNA levels of SOD1, SOD2, and SOD3 in brain tissue. The results showed that mRNA level and protein expression level of S1PR2 in the test group were higher than those in the control group three days after MCAO modeling (P < 0.05); the expression of S1PR2 increased 12 h after MCAO modeling and returned to the normal level on the 5th day, and the content of MMP9 protein in brain tissue of the test group was significantly lower than that of the control group (P < 0.05); the mRNA levels and SODs activity of SOD1, SOD2, and SOD3 in the test group were higher than those in the control group (P < 0.05). Therefore, miR-149-5p played a neuroprotective role by regulating S1PR2 to change the expression levels of SODS and MMP9.

Acute Cerebral Ischemia-Reperfusion Model by Endovascular Occlusion of the Middle Cerebral Artery in the Rat: Technical Improvements

Strokes are the third cause of death in industrialized countries, after heart disease and cancer. Among cerebrovascular accidents...

Abstract TP286: The Study of the Role and Mechanism of TRPM7 in Acute Cerebral Ischemia-Reperfusion Injury

Although the NMDA receptor was identified to mediate excitotoxicity for ischemia-reperfusion (IR) injury, its antagonists have not shown clinical efficacy. Unrelated to NMDA, the transient receptor potential cation channel, subfamily M, member 7 (TRPM7) has been reported to cause intracellular Ca 2+ overloading, oxidative stress and neuronal apoptosis. We postulated that TRPM7 could be a target for treatment of IR injury. To investigate the potential neuroprotective role of TRPM7 in IR injury, 1) qRT-PCR, Western blot and immuno-staining were used to identify the expression and localization of TRPM7 in normal rat forebrain cortex and cultured primary cortical neurons; 2) the oxygen glucose deprivation and reperfusion (OGD/R) model of primary cortical neurons was used to detect changes in TRPM7 expression and study the effect of two TRPM7 ion channel inhibitors, carvacrol and 2-Aminoethoxydiphenyl borate (2-APB), on neurons in OGD/R; 3) the rat middle cerebral artery (MCAO/R) model was used to study TRPM7 involvement and the effect of its inhibitor during the course of IR. Our results showed that: 1) TRPM7 was expressed in normal neurons and astrocytes mainly as a cell membrane protein in the rat cortex; 2) TRPM7 expression was enhanced in OGD/R treated neurons; treatment with carvacrol or 2-APB reversed the overexpression of TRPM7 in OGD/R neurons and reduced the level of Ca 2+ overload in neuronal IR injury and neuronal apoptosis; 3) TRPM7 expression was also augmented in rat cortical tissues during MCAO/R and peaked between 24-48 hours during the reperfusion stage; 4) treatment with TRPM7 inhibitors reversed TRPM7 overexpression, alleviated neuronal apoptosis, and improved neurobehavioral scores in MCAO/R rats. Our conclusions are: 1) TRPM7 is expressed in normal rat forebrain cortex and functions mainly as a cell membrane protein in neurons and astrocytes; 2) TRPM7 is overexpressed during cerebral ischemia-reperfusion in rats; 3) TRPM7 ion channel inhibitors carvacrol and 2-APB can alleviate OGD/R injury in neurons in vitro as well as cortical damage by MCAO/R in rat forebrain; 4) the mechanism of TRPM7 on neuronal injury in OGD/R and MCAO/R can contribute to its role in neuronal apoptosis and Ca 2+ influx toxicity.

Oxidative stress as a pathophysiological mechanism

The toxic effect of oxygen molecules on the human organism was first described in 1774 by J. Priestley, who compared it to the effect of a `burning candle`. Years later, superoxide dismutasis was discovered (1969) and this gave rise to the theory of the oxidative cell injury, a result of the aggressive impact of oxygen-containing forms. Contemporary literature contains an increasing amount of data on oxidative tissue and organ injury in various socially significant diseases. It is well known that the brain is vulnerable to oxidation due to its high lipid content, intensive oxygen consumption and, at the same time, relatively low antioxidant levels. Oxidative imbalance is a key mechanism of cell injury in acute (cerebral ischemia-reperfusion, epileptic seizures) as well as in chronic neurological conditions (Parkinson`s, Alzheimer, amyotrophic lateral sclerosis, etc.). Studies of patients with autoimmune diseases, such as rheumatoid arthritis, vitiligo, psoriasis, etc., as well as of patients with neoplastic diseases, demonstrate a decreased potential of the antioxidant defense of the organism. The increased production of superoxide anion radicals in the mitochondria plays a role in the development of microand macrovascular complications of diabetes mellitus. The oxidative imbalance is also of great importance in regard to the pathophysiology of many cardiovascular diseases. At present, the data concerning the role of oxidative imbalance as a mechanism of burn-induced gastric mucosal injury are few in number. Therefore, the article by Hristova, et al. `Apoptosis as a Mechanism for Burn-Induced Gastric Mucosal Injury` is very interesting. The results from the study confirm the high degree of apoptosis in the gastric mucosa due to changes in the Bax/Bcl-2 ratio in favor of the proapoptotic Bax protein. As a whole, the results from the biochemical study of the oxidative stress markers, the established microscopic changes in the gastric mucosa, and the results from the immunohistochemical tests support the hypothesis of the role of oxidative stress as an important pathophysiological mechanism of apoptosis and gastric mucosal injury in the acute period after thermal trauma.

Protective effects of scopolamine and penehyclidine hydrochloride on acute cerebral ischemia-reperfusion injury after cardiopulmonary resuscitation and effects on cytokines

The objective of this study was to investigate the protective effects of scopolamine and penehyclidine hydrochloride on acute cerebral ischemia-reperfusion injury after cardiopulmonary resuscitation, and the effect on cytokine levels. Eighty patients with cardiac arrest admitted to our hospital from June 2011 to December 2015 were recruited and randomly divided into two groups (n=40 each). Following cardiopulmonary resuscitation, scopolamine was administered in the control group, whereas penehyclidine hydrochloride was administered in the observation group. After intervention, the following medical indicators were compared between the groups: Intracranial pressure, cerebral oxygen partial pressure, cerebral perfusion pressure, assessment of the balance of cerebral oxygen supply and demand, levels of neuron-specific enolase (NSE) and blood lactic acid, levels of oxidative stress markers, and levels of inflammatory-related factors. Additionally, the areas of brain tissue edema and National Institutes of Health Stroke Scale (NIHSS) scores before and after intervention were compared. Rescue success rates of the groups were recorded. After intervention, the following indicators were lower in the observation group than in the control group: Intracranial pressure (p<0.05), levels of NSE (p<0.05), levels of blood lactic acid (p<0.05), levels of malondialdehyde (p<0.05), and levels of interleukin 6 (IL-6), tumor necrosis factor-α, IL-1, and hs-CRP (p<0.05). However, the following indicators were higher in the observation group than in the control group: Cerebral oxygen partial pressure, cerebral perfusion pressure (p<0.05), levels of CaO2, CjvO2, and CERO2 (p>0.05), and levels of superoxide dismutase and glutathione peroxidase (p<0.05). Additionally, the areas of brain tissue edema after intervention were smaller in the observation group than those before intervention and those after intervention in the control group (p<0.05). Similarly, the NIHSS scores after intervention in the observation group were lower than those before intervention and those after intervention in the control group (p<0.05). Rescue success rate was significantly higher in observation group than in control group (p<0.05). In conclusion, administration of penehyclidine following cardiopulmonary resuscitation can effectively improve cerebral perfusion pressure, lower intracranial pressure, reduce brain tissue edema and inflammation, and improve neurological function.

Effects of electroacupuncture preconditioning on cerebral infarct volume and contents of TNF-α, IL-10 in serum of rats after cerebral ischemia-reperfusion injury

To explore the effect of electroacupuncture(EA) preconditioning on cerebral infarct volume and the contents of TNF-α, IL-10 in serum of rats with cerebral ischemia-reperfusion injury. Thirty-six rats were randomly divided into a sham operation group, a model group and an EA preconditioning group, 12 rats in each group, which were further divided into 12 h and 24 h after reperfusion subgroups, 6 rats in each one. EA was used before model establishment for 2 weeks in the EA preconditioning group. The model of cerebral ischemia-reperfusion injury in rats was established with modified Longa suture method. 12 h and 24 h after reperfusion, the degree of neurological deficit was assessed by the modified behavioral scoring scale; the cerebral infarct volume was measured by TTC method and the contents of TNF-α, IL-10 in serum were detected by ELISA method. Compared with the model group, the neurological severity scores in the EA preconditioning group significantly reduced 12 h and 24 h after reperfusion (both P<0.05), the cerebral infarct volume in the EA preconditioning group significantly reduced 12 h and 24 h after reperfusion (both P<0.05). Compared with the sham operation group, the serum TNF-α, IL-10 contents in the model group increased 12 h and 24 h after reperfusion (both P<0.05). Compared with the model group, the serum TNF-α content reduced, while the serum IL-10 content increased in the EA preconditioning group 12 h after reperfusion (both P<0.05). Compared with the model group, the serum TNF-α, IL-10 contents reduced in the EA preconditioning group 24 h after reperfusion (both P<0.05). EA preconditioning can improve neurological deficit, reduce cerebral infarct volume after cerebral ischemia-reperfusion injury in rats. The mechanism may be related to the regulation of EA on the dynamic balance between pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine IL-10 in peripheral blood of cerebral ischemia-reperfusion injury in acute phase, thus alleviate acute cerebral ischemia-reperfusion inflammatory response.

The mechanisms of neuroprotective action of p-tyrosol after the global cerebral ischemia in rats

Aim. The aim of our study is to explore the mechanisms of neuroprotective effects of p-tyrosol in acute global cerebral ischemia-reperfusion in rats. Material and methods. The study was performed on 30 male rats stock Wistar (250–300 g).Animals were divided into 3 groups of 10 rats. In the control and experimental groups we performed the new 3VO model of cerebral ischemia-reperfusion, and the sham-operated animals underwent the same surgical procedures, but without the ligature imposition. Animals in the experimental group received p-tyrosol for 5 days intravenously at a daily dose of 20 mg/kg in a 2% solution. The sham-operated rats and control animals received a isotonic solution of NaCl at the same scheme. We measured rheological blood parameters and the content of products of lipid peroxidation in the brain tissue on the 5th day after cerebral ischemia-reperfusion. Results. Acute ischemia-reperfusion of the brain in rats from the control group caused the significant hemorheological abnormalities, including the increased whole blood viscosity and plasma viscosity, decreased the erythrocyte aggregation half-time and decreased red blood cell deformability index. The increase blood viscosity caused the decrease of the oxygen delivery to the tissues. The content of diene and triene conjugates, fluorescent products and the lipid oxidation index increased in the brain tissue of the control group. These abnormalities induced the death of 50% animals from the control group. Given intravenously to animals of the experimental group, p-tyrosol reduced the whole blood viscosity by 19–31%, the plasma viscosity by 6% and increased the erythrocyte deformability by 31–40%, that led to the increase of oxygen availability for tissues by 21–31% in comparison with the control group. The contents of diene and p-triene conjugates and fluorescent products in the brain tissue under course administration of p-tyrosol decreased respectively by 37%, 49 and 45%, that reflected in the decreasing of lipids oxidation index by 38% in comparison with the control group. The number of survived animals in the experimental group was 1,4 times bigger than in the control group. Conclusion. Course administration of p-tyrosol to rats with acute cerebral ischemia-reperfusion reduces the blood viscosity and the intensity of oxidative stress in the brain tissue. The results of these effects are the reduction of negative outcomes of ischemia-reperfusion of the brain and the increasing of animal surviving, that confirms the neuroprotective action of p-tyrosol in these conditions.

Hippo/MST1 signaling mediates microglial activation following acute cerebral ischemia–reperfusion injury

Cerebral ischemia–reperfusion injury is a major public health concern that causes high rates of disability and mortality in adults. Microglial activation plays a crucial role in ischemic stroke-induced alteration of the immune microenvironment. However, the mechanism underlying the triggering of microglial activation by ischemic stroke remains to be elucidated. Previously, we demonstrated that the protein kinase Hippo/MST1 plays an important role in oxidative stress-induced cell death in mammalian primary neurons and that the protein kinase c-Abl phosphorylates MST1 at Y433, which increases MST1 kinase activity. Microglial activation has been implicated as a secondary detrimental cellular response that contributes to neuronal cell death in ischemic stroke. Here, we are the first, to our knowledge, to demonstrate that MST1 mediates stroke-induced microglial activation by directly phosphorylating IκBα at residues S32 and S36. We further demonstrate that Src kinase functions upstream of MST1–IκB signaling during microglial activation. Specific deletion of MST1 in microglia mitigates stroke-induced brain injury. Therefore, we propose that Src–MST1–IκB signaling plays a critical role in stroke-induced microglial activation. Together with our previous work demonstrating that MST1 is important for oxidative stress-induced neuronal cell death, our results indicate that MST1 could represent a potent therapeutic target for ischemic stroke.

Levetiracetam Prevents Perforin Mediated Neuronal Injury Induced by Acute Cerebral Ischemia Reperfusion.

The purpose of this study is to explore the neuroprotection mechanism of levetiracetam (LEV) with acute focal cerebral ischemia-reperfusion (I/P) mouse. The cerebral artery I/P animal model was prepared with a middle artery cerebral occlusion method. For drug intervention, mice were intraperitoneally injected with LEV with a dose of either 15 or 150mg/kg. Neuronal injury was evaluated by measuring the infarct area, apoptosis ratio, and observation of blood-brain barrier ultrastructure with transmission electron microscope. CD8(+) antibody and perforin antibody were used to make cross-reference screen through flow cytometry to determine a perforin-positive rate in CD8(+) T lymphocytes (PFN + %). Injection of LEV can reduce infarct area, apoptosis ratio, and blood-brain barrier damage 24h later after acute I/P in WT mice. In vitro, perforin can lower hippocampal neuron viability. In vivo, removing perforin can relieve neuronal injury. High dose injection of LEV (150mg/kg) can inhibit perforin secreting from CD8(+)T lymphocytes. In addition, LEV can still protect neurons with perforin knockout mice. Therefore, our results suggested that LEV may contribute to neuron protection after cerebral ischemia reperfusion. The possible mechanism may be related with perforin release. However, we cannot roll out other mechanisms.

Orally administrated pterostilbene attenuates acute cerebral ischemia–reperfusion injury in a dose- and time-dependent manner in mice

Pterostilbene (3,5-dimethoxy-4-hydroxystilbene) is a component of blueberry. It has been reported that long-term treatment with blueberry has a neuroprotective effect. However, it has not been reported whether pterostilbene is effective in attenuating cerebral ischemia/reperfusion (I/R) injury. In the present study, focal cerebral ischemia was induced by middle cerebral artery occlusion for 90min followed by reperfusion. To observe the dose-dependent effect, pterostilbene (2.5–80mg/kg, ig) was administered for 3days before ischemia. To determine the time-dependent effect, pterostilbene (10mg/kg, ig) was administered as a single dose at 0, 1, or 3h after reperfusion. Twenty-four hours after I/R, pterostilbene dose-dependently improved neurological function, reduced brain infarct volume, and alleviated brain edema. The most effective dose was 10mg/kg; the therapeutic time window was within 1h after I/R and treatment immediately after reperfusion showed the best protective effect. The protective effect is further confirmed by the results that post-ischemic treatment with pterostilbene (10mg/kg) significantly improved motor function, alleviated blood brain barrier disruption, increased neurons survival and reduced cell apoptosis in cortical penumbra after cerebral I/R. We also found that pterostilbene (10mg/kg) significantly reversed the increased content of malondialdehyde and the decreased activity of superoxide dismutase in the ipsilateral hemisphere. Furthermore, pterostilbene decreased the oxidative stress markers 4-hydroxynonenal and 8-hydroxyguanosine positive cells in the cortical penumbra. All these findings indicate that pterostilbene dose- and time-dependently exerts a neuroprotective effect against acute cerebral I/R injury. This neuroprotective effect of pterostilbene may be associated with its inhibition of oxidative stress and subsequent neuronal apoptosis in the cortical penumbra.

Protective effect of different concentrations of normobaric oxygen in early cerebral ischemic-reper-fusion injury rat model

Objective To observe the protective effect of different concentrations of normobaric oxygen (NBO) on rats with acute cerebral ischemia reperfusion in early time.Methods 120 rats were divided randomly into high,medium and low NBO treatment groups and model group.Every group was divided into 3,6,12,24,48,and 72 h subgroups after ischemia reperfusion (n =5 each).The neurologic impairment scores were assessed in rats before and after oxygen inhalation,and the expression of Caspase-9 and Caspase-3 protein was detecte 4 d by using immunohistochemistry.Results Neurologic impairment scores in NBO treatment groups were decreased to varyoing degrees.There was statistically significant difference beween the high NBO treatment group (1.40 ±0.55,1.20 ±0.45,1.40 ±0.55,1.20 ±0.84,1.20 ±0.84,1.00±0.71) and the model group (2.20 ±0.45,2.20 ±0.84,2.20 ±0.45,2.20 ±0.45,2.80 ±0.84,2.60 ± 0.54) at each time point (P ＜ 0.05).The expression of Caspase-9 and Caspase-3 protein in the high,medium and low NBO treatment groups was lower than in the model group (P ＜ 0.05) at each time point.Conclusion The high concentration of NBO could reduce the expression of Caspase-9 and Caspase-3 protein obviously in rats with acute cerebral ischemia reperfusion and enhance the neurological function in early time,and medium and low concentrations of NBO had obvious effect delay as compared with high concentration of NBO. Key words: Normobaric oxygen; Cerebral ischemia; Reperfusion injury; Caspase-9 ; Caspase-3