Protection In Cerebral Ischemia Research Articles

Role of Qufeng Tongqiao Prescription in the protection of cerebral ischemia and associated molecular network mechanism.

To explore the of Qufeng Tongqiao Prescription in the treatment of cerebral ischemia-reperfusion (CIR) and associated molecular network mechanism. Venny diagram, gene ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis, protein-protein interaction (PPI), hub genes mining, molecular docking, combined with animal experiments and Nissl stain were performed to determine the molecular network mechanism of Qufeng Tongqiao Prescription for CIR treatment. Fifty three intersecting genes between Qufeng Tongqiao Prescription and cerebral ischemia reperfusion were acquired from Venny analysis. GO analysis showed that the main biological process (BP) was response to lipopolysaccharide, and the main cell localization (CC) process was membrane raft, while the most important molecular function (MF) process is Cytokine receptor binding. Moreover, AGE-RAGE signaling pathway in diabetic complications is the most important signaling pathway in KEGG pathway. Through molecular docking, it was found that Astragalus membranaceus was docked with MAPK14, IL4, FOS, IL6, and JUN; pueraria membranaceus was directly docked with JUN and IL4; Acorus acorus was linked to JUN and MAPK14; Ganoderma ganoderma and human were involved in JUN docking, and Ligusticum chuanqi and pueraria could not be docked with MAPK14, respectively. The results of animal experiments showed that Qufeng Tongqiao Prescription significantly improved behavioral performance and reduced the number of neuronal deaths in rats subjected to CIR, and molecular mechanisms are associated with FOS, IL-6, IL4, JUN, and MAPK14, of there, IL-6, as a vital candidator, which has been confirmed by immunostaining detection. Together, Qufeng Tongqiao Prescription has positive therapeutic effect on CIR, and the underlying mechanism is involved MAPK14, FOS, IL4, and JUN network, while IL-6 may be as a vital target.

Isoflurane Conditioning-Induced Delayed Cerebral Ischemia Protection in Subarachnoid Hemorrhage-Role of Inducible Nitric Oxide Synthase.

Background Recent evidence implicates inflammation as a key driver in delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage (SAH). Inducible nitric oxide synthase (iNOS) is one of the known major mediators of inflammation. We previously showed that an inhalational anesthetic, isoflurane, provides strong protection against delayed cerebral ischemia after SAH. Our current study aims to define the role of iNOS in isoflurane conditioning-induced protection against delayed cerebral ischemia in a mouse model of SAH. Methods and Results The experiments used 10- to 14-week-old male wild-type (C57BL/6) and iNOS global knockout mice. Anesthetic conditioning was initiated 1 hour after SAH with isoflurane 2% for 1 hour. Isoflurane-induced changes in iNOS expression were measured. N-(3-(aminomethyl) benzyl) acetamidine, a highly selective iNOS inhibitor, was injected intraperitoneally immediately after SAH and then daily. Vasospasm, microvessel thrombosis, and neurological assessment was performed. Data were analyzed by 1-way ANOVA and 2-way repeated measures ANOVA followed by Student Newman Keuls comparison test. Statistical significance was set at P<0.05. Isoflurane conditioning downregulated iNOS expression in naïve and SAH mice. N-(3-(aminomethyl) benzyl) acetamidine attenuated large artery vasospasm and microvessel thrombosis and improved neurological deficits in wild-type animals. iNOS knockout mice were significantly resistant to vasospasm, microvessel thrombosis, and neurological deficits induced by SAH. Combining isoflurane with N-(3-(aminomethyl) benzyl) acetamidine did not offer extra protection, nor did treating iNOS knockout mice with isoflurane. Conclusions Isoflurane conditioning-induced delayed cerebral ischemia protection appears to be mediated by downregulating iNOS. iNOS is a potential therapeutic target to improve outcomes after SAH.

Effect of VEGF on neurological impairment and prognosis of acute cerebral infarction patients: A retrospective case-control study.

Due to the complex pathological mechanism of acute cerebral infarction, the role of vascular endothelial growth factor (VEGF) on the disease is not clear. Therefore, a retrospective case-control study was performed to explore the effect of VEGF on neurological impairment and prognosis of acute cerebral infarction patients. A total of 100 patients with acute cerebral infarction admitted to our hospital from April 2021 to April 2022 were selected. Blood samples from all patients would be routinely collected to detect the expression of serum VEGF. Pearson chi-square, Spearman correlation and univariate Logistic regression were used to analyze the clinical data to explore the relationship between VEGF expression and basic information, stroke degree, quality of life, and prognosis of patients. To determine whether VEGF can provide relevant basis for the early prevention and prognostic treatment of acute cerebral infarction. And multivariate logistic regression was used to calculate the odds ratio between each variable and VEGF expression. Pearson chi-square test and Spearman correlation coefficient showed that sex, degree of stroke, limb convulsions, loss of consciousness, hemiplegia, aphasia, mental functioning score, overall quality of life score, and short-term prognosis were significantly correlated with VEGF expression in 100 patients. Univariate logistic regression was used to describe the ORs and 95% confidence interval of subjects at the univariate level, and the degree of stroke (OR = 83.333, P < 0.001), tic of limbs (OR = 26.316, P < 0.001), loss of consciousness (OR = 23.256, P < 0.001), hemiplegia (OR = 62.500, P < 0.001), aphasia (OR = 76.923, P < 0.001), mental functioning score (OR = 7.937, P < 0.001), overall quality of life score (OR = 5.464, P < 0.001), short-term prognosis (OR = 37.037, P < 0.001) was significantly correlated with the high expression of VEGF. The level of serum VEGF was positively correlated with neurological impairment degree and prognosis in patients with acute cerebral infarction, the more severe the degree of stroke and the worse the prognosis.

Mechanism underlying sevoflurane-induced protection in cerebral ischemia–reperfusion injury

Abstract Cerebral ischemia is an extremely complex disease that can be caused by a variety of factors. Cerebral ischemia can cause great harm to human body. Sevoflurane is a volatile anesthetic that is frequently used in clinic, and has a lot of advantages, such as quick induction of general anesthesia, quick anesthesia recovery, no respiratory tract irritation, muscle relaxation, and small cycle effect. The mechanism of sevoflurane preconditioning or post-treatment induction is poorly understood. The purpose of this study was to illustrate the mechanism underlying sevoflurane-induced protection in cerebral ischemia–reperfusion injury and also provide theoretical guidance for future research.

New insights into targeting mitochondria in ischemic injury.

Stroke is the leading cause of adult disability and death worldwide. Mitochondrial dysfunction has been recognized as a marker of neuronal death during ischemic stroke. Maintaining the function of mitochondria is important for improving the survival of neurons and maintaining neuronal function. Damaged mitochondria induce neuronal cell apoptosis by releasing reactive oxygen species (ROS) and pro-apoptotic factors. Mitochondrial fission and fusion processes and mitophagy are of great importance to mitochondrial quality control. This paper reviews the dynamic changes in mitochondria, the roles of mitochondria in different cell types, and related signaling pathways in ischemic stroke. This review describes in detail the role of mitochondria in the process of neuronal injury and protection in cerebral ischemia, and integrates neuroprotective drugs targeting mitochondria in recent years, which may provide a theoretical basis for the progress of treatment of ischemic stroke. The potential of mitochondrial-targeted therapy is also emphasized, which provides valuable insights for clinical research.

Role of Endothelial Nitric Oxide Synthase in Isoflurane Conditioning-Induced Neurovascular Protection in Subarachnoid Hemorrhage.

BackgroundDelayed cerebral ischemia remains a common and profound risk factor for poor outcome after subarachnoid hemorrhage (SAH). The aim of our current study is to define the role of endothelial nitric oxide synthase (eNOS) in isoflurane conditioning‐induced neurovascular protection after SAH.Methods and ResultsTen‐ to 14‐week‐old male wild‐type mice (C57BL/6) as controls and eNOS knockout male mice (strain # 002684) were obtained for the study. Animals underwent either sham surgery, SAH surgery, or SAH with isoflurane conditioning. Anesthetic post conditioning was performed with isoflurane 2% for 1 hour, 1 hour after SAH. Normothermia was maintained with the homeothermic blanket. In a separate cohort, nitric oxide synthase was inhibited by a pan nitric oxide synthase inhibitor, L‐nitroarginine methyl ester. Vasospasm measurement was assessed 72 hours after SAH and neurological function was assessed daily. Isoflurane‐induced changes in the eNOS protein expression were measured. eNOS protein expression was significantly increased by isoflurane conditioning in naïve mice as well as mice subjected to SAH. Vasospasm of the middle cerebral artery and neurological deficits were evident following SAH versus sham surgery, both in wild‐type mice and eNOS knockout mice. Isoflurane conditioning attenuated vasospasm and neurological deficits in wild‐type mice. This delayed cerebral ischemia protection was lost in L‐nitroarginine methyl ester ‐administered mice and eNOS knockout mice.ConclusionsOur data indicate isoflurane conditioning provides robust protection against SAH‐induced vasospasm and neurological deficits, and that this delayed cerebral ischemia protection is critically mediated via isoflurane‐induced augmentation of eNOS.

Neuroprotective Effects and Mechanisms of Zhenlong Xingnao Capsule in In Vivo and In Vitro Models of Hypoxia.

Zhenlong Xingnao Capsule (ZXC) is a Tibetan medicine used to treat ischemic stroke. In this study, we determined the in vitro and in vivo effects of ZXC on reactive oxygen species (ROS) in a mouse BV-2 microglial cell hypoxia-reoxygenation and rat middle cerebral artery occlusion infarction models. We aimed to clarify the role of ZXC in cerebral ischemia protection; reveal amino acid neurotransmitter changes in the frontal cortex after drug intervention; determine mRNA and protein expression changes in Bcl-2, Bax, caspase-3, P38, and nuclear factor (NF)-кB in the frontal cortex and changes in antioxidant indices in the brain; and elucidate the mechanisms underlying ZXC action. After hypoxia-reoxygenation, ROS levels were significantly increased in BV-2 cells, and their levels decreased after treatment with ZXC. ZXC had protective effects on ischemic/anoxic injury in vitro and in vivo by downregulating the expressions of caspase-3 and NF-кB mRNA during ischemia and reperfusion and that of p38 and caspase-3 during acute ischemia and reperfusion as well as the steady-state levels of excitatory amino acids/inhibitory amino acids and by improving the total antioxidant capacity and total superoxide dismutase activities during ischemia. These findings provide new molecular evidence for the mechanisms underlying ZXC action.

Activation of Akt by SC79 decreased cerebral infarct in early cerebral ischemia-reperfusion despite increased BBB disruption

Activation of Akt has been suggested to produce neuronal protection in cerebral ischemia. Decreasing blood-brain barrier (BBB) disruption has been associated with a better neuronal outcome in cerebral ischemia. We hypothesized that activation of Akt would decrease BBB disruption and contribute to decreasing the size of infarct in the early stage of cerebral ischemia-reperfusion within the therapeutic window. Transient middle cerebral artery occlusion (MCAO) was performed in rats under isoflurane anesthesia with controlled ventilation. Rats were treated with SC79 (a selective Akt activator which is cell and BBB permeable) 0.05 mg/kg × 3 i.p. or vehicle i.p. perioperatively. After one hour of MCAO and two hours of reperfusion, the transfer coefficient (Ki) of 14C-α-aminoisobutyric acid (14C-AIB, molecular weight 104 Da) and the volume of 3H-dextran (molecular weight 70,000 Da) distribution were determined to measure the degree of BBB disruption. At the same time point, the size of infarction was determined using tetrazolium staining. In an additional group of rats, a higher dose of SC79 (0.5 mg/kg × 3) was administered to determine the size of infarct. Administration of SC79 increased the Ki in the ischemic-reperfused cortex (IR-C, +32%, p < 0.05) as well as in the contralateral cortex (CC, +35%, p < 0.05) when compared with the untreated animals with MCAO/reperfusion. The volume of dextran distribution was not significantly changed by SC79. SC79 treatment significantly produced a decrease in the percentage of cortical infarct out of total cortical area (12.7 ± 1.7% vs 6.9 ± 0.9%, p < 0.001). Increasing the dose of SC79 by ten times did not significantly affect the size of cortical infarct. Contrary to our hypothesis, our data demonstrated that SC79 decreased the size of the infarct in the ischemic-reperfused cortex despite an increase in BBB disruption. Our data suggest the importance of activation of Akt for neuronal survival in the early stage of cerebral ischemia-reperfusion within the therapeutic window and that the mechanism of neuroprotection may not be related to the BBB effects of SC79.

Abstract WP295: Remote Limb Ischemic Conditioning in Murine Focal Cerebral Ischemia

Background &amp; Aims: Remote ischemic conditioning (RIC) could induce brain protection in cerebral ischemia. The conditioning can be divided into pre-, per- and post-conditioning. The aim of this study is to clarify which RIC is the most effective in murine focal ischemia. Methods: Adult male C57BL/6 mice were used in this study. Transient focal cerebral ischemia was produced with nylon-suture model by occluding middle cerebral artery (MCAO) for 45 minutes. Cortical cerebral blood flow (rCBF) was continuously measured during ischemia with laser Doppler flowmeter. Twenty-four hours after MCAO, the animals were sacrificed and their brains were removed. After cutting coronal 1-mm brain sections, infarct volume was measured after TTC staining. Fifty mice were divided into five groups (each n=10); sham RIC group, delayed preRIC group (RIC 24 hours before MCAO), early preRIC group (RIC 5 minutes before MCAO), perRIC group (RIC during MCAO), and postRIC group (RIC 5 minutes after MCAO). Hind limb ischemia was induced by making the snare as tight as possible using a hemostatic forceps for 5 minutes followed by loosening it for 5 minutes. Four cycles were performed as RIC. Results: Infarct volume were 58.8±10.1 mm 3 in sham RIC, 54.8±19.4 mm 3 in delayed preRIC, 69.3±10.8 mm 3 in early preRIC, 38.0±22.1 mm 3 in perRIC, and 64.5±13.5 mm 3 in postRIC groups. Infarct volume in perRIC was significantly smaller than that in sham RIC and other groups (P&lt;0.01). However, infarct volume of other RIC groups was not different with sham RIC group. After MCAO, rCBF reduced to 15.6% of baseline level in sham RIC, 11.2% in delayed preRIC, 11.9% in early preRIC, 13.4% in perRIC, and 10.8% in postRIC group. No difference was found in residual rCBF among all groups. At the end of MCAO, rCBF compared to rCBF immediate after occlusion was 102±21% in sham RIC, 112±25% in delayed preRIC, 98±22% in early preRIC, 131±33% in perRIC and 105±19% postRIC groups. Relative rCBF change at the end of MCAO in perRIC was significantly more than that in sham RIC group (P&lt;0.05). Conclusions: Among four RIC procedures, only perRIC showed clear brain protection against transient MCAO. Change during rCBF may suggest that enhancement of collateral circulation play a role in part on brain protective effect of perRIC.

Effect of Baicalin-loaded PEGylated cationic solid lipid nanoparticles modified by OX26 antibody on regulating the levels of baicalin and amino acids during cerebral ischemia–reperfusion in rats

Baicalin has many pharmacological activities, including neuroprotective function against ischemia and neurodegeneration. In our previous study, we found that Baicalin-loaded PEGylated cationic solid lipid nanoparticles modified by OX26 antibody (OX26-PEG-CSLN) might be a promising carrier to deliver drugs across the blood–brain barrier for the treatment of brain diseases. So, the aim of this present study was to further elucidate the mechanisms of OX26-PEG-CSLN cerebral ischemia protection by monitoring the changes of extracellular amino acids. In addition, we investigated the effect of OX26-PEG-CSLN on the excitotoxic neuronal injury as well as the pharmacokinetic profiles of baicalin in cerebrospinal fluid during ischemia–reperfusion period. The cerebrospinal fluid was collected by a microdialysis technique and divided into two parts – one part for pharmacokinetic study of baicalin using LC–MS/MS method and the other for pharmacodynamic study which was done by pre- column derivatization of the amino acids and analysis using a high-performance liquid chromatography with fluorescence detector (HPLC-FLD). The pharmacokinetic study showed that the AUC value of OX26-PEG-CSLN was 5.69-fold higher than that of the baicalin solution (Sol) (P<0.05) and the Cmax value of OX26-PEG-CSLN was 6.84-fold higher than that of the Sol (P<0.05). Moreover, the extracellular levels of glutamate (Glu), aspartic acid (Asp), glycine (Gly), taurine (Tau) and γ-aminobutyric acid (GABA) were measured for monitoring the imbalance of amino acids caused by ischemia and reperfusion. The excitotoxic index (EI) was also calculated for evaluating the imbalance between excitatory amino acid and inhibitory amino acid. The pharmacodynamic study showed that OX26-PEG-CSLN had stronger effect than Sol in reducing the content of aspartic, glutamic acid and increasing the concentrations of glycine, taurine and γ-aminobutyric acid during ischemia–reperfusion period. In conclusion, OX26-PEG-CSLN improved uptake of baicalin across the BBB into the brain, and elevated bioavailability of baicalin in cerebral spinal fluid of rats under the cerebral ischemia–reperfusion injury. OX26-PEG-CSLN had much higher protection effect against cerebral ischemia injury than Sol by relieving the excitotoxic neuronal injury via regulating amino acid levels in cerebral spinal fluid.

Beta-asarone, a major component of Acorus tatarinowii Schott, attenuates focal cerebral ischemia induced by middle cerebral artery occlusion in rats

BackgroundIschemic hypoxic brain injury often causes irreversible brain damage. The lack of effective and widely applicable pharmacological treatments for ischemic stroke patients may explain a growing interest in traditional medicines. β-Asarone, which has significant pharmacological effects on the central nervous system (CNS), was used in the prevention of cerebral ischemia in this paper.MethodsThe right middle cerebral artery occlusion model was used in the study. The effects of β-Asarone on mortality rate, neurobehavior, grip strength, lactate dehydrogenase, glutathione content, Lipid peroxidation, glutathione peroxidase activity, glutathione reductase activity, catalase activity, Na+-K+-ATPase activity and glutathione S transferase activity in a rat model were studied respectively.Resultsβ-Asarone significantly improved the neurological outcome after cerebral ischemia and reperfusion in terms of neurobehavioral function in rats. Meanwhile, supplementation of β-Asarone significantly boosted the defense mechanism against cerebral ischemia via increasing antioxidants activity related to lesion pathogenesis. Restoration of the antioxidant homeostasis in the brain after reperfusion may help the brain recover from ischemic injury.ConclusionsThese experimental results suggest that complement β-Asarone is protective against cerebral ischemia in specific way. The administration of β-Asarone could reduce focal cerebral ischemic/reperfusion injury. The Mechanism of β-Asarone in protection of cerebral ischemia was via increasing antioxidants activity related to lesion pathogenesis.

Altered plasma and brain disposition of isopropylidene shikimic acid liposome in rats and the brain protection in cerebral ischemia–reperfusion

Context: Cerebral ischemia–reperfusion (I/R) injury is a secondary injury caused by oxidative stresses and inflammatory responses after recovery from cerebral ischemia. Brain protective drugs were used to reduce the injury. In order to improve the distribution in brain and enhance the brain-protective efficacy, some pharmaceutical technologies were used to achieve brain targeting delivery.Objective: To investigate the physiological disposition of ISA liposome, and provide references for the further study about high-efficacy brain-protective preparations for I/R injury.Materials and methods: Comparative studies were carried out. The pharmacodynamics in t-MCAO model rats were studied first, and then the pharmacokinetics and brain distribution of the two preparations were determined.Results: At the same dose, the efficacy of ISA liposome was better (P < 0.05). The efficacy was dose dependent, with significant difference of 20 mg/kg (P < 0.01) and indistinctive difference of 10 mg/kg (P = 0.22), compared with vehicle-treated rats. The parameters, T1/2β, MRT and AUC were different significantly between the two preparations. The enhancement of brain distribution for ISA in the liposome was obvious, with the maximum concentration 7.18 μg/g, while close to zero for the solution group.Discussion and conclusion: ISA liposome could increase the distribution in brain and enhance the efficacy significantly. The results revealed that the liposomal DDS was potential as a novel strategy for the treatment of cerebral I/R injury. In addition, further targeted modification, such as PEG-modified liposomes, which possess a long circulating property in the bloodstream, would further improve the targeting delivery to the brain and lead to more significant efficacy.

Neurovascular protection conferred by 2-BFI treatment during rat cerebral ischemia

Stroke is caused by vascular dysfunction and currently there are no effective therapeutics to stroke induced brain damage. In contrast to an intense emphasis on neuroprotection, relatively few studies have addressed means of vascular protection in cerebral ischemia. Here we discovered that the ligand to immidazolin receptor, 2-BFI, not only provided potent neuroprotection during middle cerebral artery occlusion in rat, which confirmed our previous reports, but also protected the integrity of the cerebral vasculature. Treatment with 2-BFI twice daily after the occlusion of the middle cerebral artery for 14d significantly improved the neurological deficits, reduced brain infarction, and importantly, protected the cerebral vasculature as evidenced by the increased expression of an endothelial marker, von Willebrand factor, and better preservation of the cerebral vasculature, as viewed under a confocal microscope on rat brain perfused with FITC-labeled dextran. These results indicated that 2-BFI contributes to protection of neurovasculature. Understanding the molecular mechanisms could eventually lead to development of more effective therapies for stroke.

Experimental study of cerebral ischemia protection of cerebral collateral circulation reconstruction induced by multiple ischemic preconditioning

Objective We used ischemic preconditioning method by blocking rabbit's right carotid artery at intervals repeatedly and increasing blocking time to reconstruct collateral circulation. Cerebral protection effects were investigated after the right carotid artery was permanently blocked. Methods 48 rabbits were randomly divided into experimental and control groups (n=24).The right common carotid artery of the animals in the experimental group was compressed at intervals repeatedly. We blocked the right carotid artery blood flow by the Inflatable balloon, ischemic time=number of times×5+40(min), 2 times per day. The longest blocking time is 4 h (20th days). The procedure of control group was the same as that of experimental group, except that the carotid artery blood flow was not blocked. The establishment of a right collateral circulation in the rabbit brain was observed with Digital Subtraction Angiography (DSA) on the 1st, 10th and 20th day respectively. The blood flow in the right common carotid artery was completely blocked at 20th day. The neurological deficit score was observed at 1, 3, 6, 24 h. Then we got brain tissue specimens and compared the brain water content and pathological changes between the two groups. The number of brain microvascular of the corresponding places was also counted. Results During the experiment, no abnormal behaviors such as excitement, agitation, lethargy were observed in either group. DSA showed that contrast medium passed into the right middle cerebral artery Willis ring on the 10th day.Compared with the 1st day, the blood vessels on the right side were much clearer in DSA. On the 20th day there was almost no difference between the left and right sides in vascular imaging. Experimental group's neurological deficit score and water content were lower than those of the control group's (P＜0.05). Observation showed that there were more brain microvascular in the right side (ischemic side) pathological specimens of the experimental group 5.3±0.5 than control group 3.5±0.4 (P＜O.05) under microscope at 400 times. Conclusion By multiple ischemic preconditioning cerebral artery Willis ring and cerebral collateral circulation would be reconstructed, and it had obvious protective effect on cerebral ischemia resulted from completely blocked carotid arteries. Key words: Ischemic preconditioning; Collateral circulation; Neurological deficit score; Cerebral ischemia

The Connexin43 C-Terminal Region Mediates Neuroprotection During Stroke

Connexin43 plays an important role in neuroprotection in experimental stroke models; reducing the expression of this gap junction protein in astrocytes enhances injury upon middle cerebral artery occlusion (MCAO). Because the C-terminal region of connexin43 isimportant for channel activity, we carried out MCAO stroke experiments in mice expressing a truncated form of connexin43 (Cx43DeltaCT mice). Brain sections were analyzed for infarct volume, astrogliosis, and inflammatory cell invasion 4 days after MCAO. Adult cortices and astrocyte cultures were examined for connexin43 (Cx43) expression by immunohistochemistry and Western blot. Cultured astrocytes were also examined for dye coupling, channel conductance, hemichannel activity, and Ca wave propagation. The Cx43DeltaCT mice exhibit enhanced cerebral injury after stroke. Astrogliosis was reduced and inflammatory cell invasion was increased inthe peri-infarct region in these mice compared with controls; Cx43 expression was also altered. Lastly, cultured astrocytes from Cx43DeltaCT mice were less coupled and displayed alterations in channel gating, hemichannel activity, and Ca wave properties. These results suggest that astrocytic Cx43 contributed to the regulation of cell death after stroke and support the view that the Cx43 C-terminal region is important in protection in cerebral ischemia.

Exploration of the effect of inhibitor of matrix metalloproteinase-9 on blood brain barrier in cardiopulmonary resuscitation in rats

To explore the effect of inhibitor of matrix metalloproteinase-9 (MMP-9, SB-3CT) on blood brain barrier (BBB) after cardiopulmonary resuscitation (CPR) in rats. Rats were randomly divided into three groups: the sham-operated group, the resuscitation control group, and the resuscitation treatment group. Cardiac arrest was produced by clamping the endotracheal intubation, and CPR was executed 1 minute later. In the resuscitation treatment group, SB-3CT (25 mg/kg) was injected intraperitoneally after the restoration of spontaneous circulation (ROSC). The rats were executed immediately, and 0, 3, 9, 24 and 48 hours after the treatment. BBB was examined, and the expression of MMP-9 protein and MMP-9 mRNA in brain tissue were detected, and the ultrastructure of brain tissue was studied with electron microscopy. In the sham-operated group, the water content, Evans blue content, MMP-9 protein, and MMP-9 mRNA did not change significantly, and there was no obvious change in microstructure of brain tissue. The expression of MMP-9 protein and MMP-9 mRNA in the resuscitation control group were obviously up-regulated at 3 hours after CPR, peaking at 24 hours. There was also significant change in BBB. The differences were significant statistically compared with sham-operated group. The changes in the resuscitation treatment group were similar to the resuscitation control group, but the levels were lower than those of the resuscitation control group (P<0.05 or P<0.01). The specific inhibitor of MMP-9 (SB-3CT) could decreased the expression of MMP-9, the injury of BBB, and cerebral edema in the cerebral ischemia model with CPR rats, and the protection of cerebral ischemia/reperfusion (I/R) injury after CPR is obvious.

Mechanisms of lumbrokinase in protection of cerebral ischemia

The present study was designed to explore the mechanisms involved in the anti-ischemic action of lumbrokinase (LK) in brain. The enzyme immunoassay, spectrofluorimeter and flow cytometry were used to detect the level of adenosine 3′,5′-cyclic monophosphate (cAMP) and guanosine 3′,5′-cyclic monophosphate (cGMP), the Ca 2+ mobilization, and human platelet surface antigen expression in order to elucidate the anti-platelet action involved in LK cerebroprotection. RT-PCR and western blot were used to identify the role of Intercellular adhesion molecule-1 (ICAM-1) and Janus Kinase1/Signal Transducers and Activators of Transcription1 (JAK1/STAT1) pathway in protecting brain against ischemic injury by anti-thrombosis and anti-apoptosis. Results showed that LK significantly potentiated the activity of adenylate cyclase (AC), increased the cAMP level in vivo, remarkably inhibited the rise of rat platelet intracellular Ca 2+ ([Ca 2+] i), and attenuated the expression of Glycoprotein IIB/IIIA (GPIIB/IIIA) and P-selectin in human platelet stimulated by thrombin in vitro. Furthermore, the expressions of ICAM-1 and JAK1/STAT1 were remarkably regulated by LK in Human Umbilical Vein Endothelial Cell (HUVEC) and ischemic cerebral tissues. These data indicated that the anti-ischemic activity of LK was due to its anti-platelet activity by elevating cAMP level and attenuating the calcium release from calcium stores, the anti-thrombosis action due to inhibiting of ICAM-1 expression, and the anti-apoptotic effect due to the activation of JAK1/STAT1 pathway.

Surgical treatment of aortic arch aneurysms using selective cerebral perfusion. Experience with 100 patients.

Hundred consecutive patients were operated on for aortic arch aneurysms between January 1986 and October 1993. All operations were performed with the aid of extracorporeal circulation, blood cardioplegia for myocardial protection, and selective cerebral perfusion (SCP) for protection of cerebral ischemia during aortic arch repair. Forty-four patients (44%) had an emergency operation because of frank or impending rupture of aneurysms or acute aortic dissection. Eighty-three patients (83%) underwent total arch replacement, and 54 had concomitant procedures including aortic valve resuspension, aortic valve replacement (AVR), composite graft replacement and coronary artery bypass grafting (CABG). The overall early (30-day) mortality rate was 16%. Multivariate analysis revealed, as significant risk factors, preoperative cardiopulmonary resuscitation, renal-mesenteric ischemia due to acute dissection, previous ascending aorta/arch operation and preoperative stroke. Of the 71 (71%) patients who were free of these risk factors, only one (1.4%) died. One patient (1%), who was preoperatively in shock state, had a distinct stroke. The present data suggest that SCP is a useful method for aortic arch aneurysm operation requiring complex repair of the aortic arch.

Decreased Glutamate Release during Hypothyroidism May Contribute to Protection in Cerebral Ischemia

Hypothyroidism protects the brain from the effects of transient forebrain ischemia in gerbils. The mechanism for this protection is not fully understood. In this study we looked at the release of glutamate during ischemia in gerbils exposed to surgical hypothyroidism (n = 7), chemical hypothyroidism (n = 8), and surgical hypothyroidism thyroxine-treated (n = 3) and compared them to control euthyroid animals (n = 8). The duration of ischemia was 10 min. Glutamate release was measured with in vivo microdialysis. Microdialysis analysis began 2 h after the placement of the probes (to stabilize the baseline) and collections were obtained in 10-min samples. During ischemia, there was an increase in the release of glutamate that returned to the baseline within 20 min following the insult. In animals made hypothyroid surgically and chemically, the extent of glutamate release was significantly lower than that in the controls. The release of glutamate in the surgically hypothyroid thyroxine-treated animals was similar to that in controls. The attenuated glutamate release could be a mechanism of protection during ischemia in hypothyroid gerbils.

High extracellular GABA levels in hippocampus--as a mechanism of neuronal protection in cerebral ischemia in adrenalectomized gerbils.

Adrenalectomy protects the brain from delayed neuronal damage that occurs following transient forebrain ischemia in gerbils. Gamma-amino butyric acid (GABA) and GABA-mimetic drugs also have a neuro-protective effect. In this study we estimated the extracellular glutamate and GABA levels in the hippocampus during transient forebrain ischemia in adrenelectomized gerbils (n = 8) compared to controls (n = 6). Duration of ischemia was 10 min, and glutamate and GABA levels were measured with in vivo microdialysis. Microdialysis was started 2 h after the placement of a probe (to stabilise baseline) and samples were collected at 10-min intervals. The pattern of glutamate release did not show any difference between adrenelectomized animals and controls. Adrenelectomized animals showed marked increase in GABA levels during ischemia and upto 30 min after ischemia (P = 0.0287, 2-way ANOVA for repeated measurements). The enhanced GABA release may be one of the possible mechanisms of neuronal protection against ischemia in adrenelectomized gerbils.