Cerebral Ischemia-reperfusion Group Research Articles

Recombinant Adenovirus-Mediated HIF-lα Ameliorates Neurological Dysfunction by Improving Energy Metabolism in Ischemic Penumbra After Cerebral Ischemia-Reperfusion in Rats.

Hypoxia inducible factor-1α (HIF-1α) regulates glucose metabolism during ischemia. This study investigated the effect of recombinant adenovirus HIF-1ɑ on neurological function and energy metabolism in a rat cerebral ischemia-reperfusion model. Rats were divided into four groups: sham-operated (Sham) group, cerebral ischemia-reperfusion (CIR) group, recombinant adenovirus empty vector (Ad) group, and recombinant adenovirus-mediated HIF-1α (AdHIF-1α) group. The AdHIF-1α group and the Ad group were injected with AdHIF-1α and Ad in the lateral ventricle. The mNSS was performed at post-ischemia day 0 (P0) and P1, P14 and P28. At P14, the cerebral infarct volume was compared. At P28, HE staining, Nissl stains and TUNEL staining were performed. The expression of HIF-1α, GLUT1 and PFKFB3 were evaluated by Western Blot and immunohistochemistry. High performance liquid chromatography (HPLC) was used to determine the expression of GLUT1 and PFKFB3, and the level of energy metabolites: ATP, ADP and AMP. mNSS scores in the AdHIF-1α group were consistently lower than those in the CIR and Ad groups from P14 (P < 0.05) and Ad groups (P < 0.05). The cerebral infarct volume was reduced in the AdHIF-1α group compared with that in CIR group and Ad group (P < 0.05). At P28, HE showed better pathological changes in AdHIF-1α group. The number of Nissl bodies was increased in the AdHIF-1α group compared with the CIR and Ad groups (P < 0.05). The number of apoptotic cells in the AdHIF-1α group was fewer than that in the CIR and Ad groups (P < 0.05). The expression of HIF-1α, GLUT1 and PFKFB3 was significantly higher in the AdHIF-1α group compared with the CIR and Ad groups (P < 0.05). The ATP, ADP and AMP in the ischemic penumbra were also higher in the AdHIF-1α group (P < 0.05). HIF-lα promoted neurological function recovery and decreased cerebral infarct volume in rats after cerebral ischemia-reperfusion injury by improving energy metabolism.

Protective effects of anise in prevention of cerebral ischemia reperfusion injury in rats.

The aim of this study is to determine the protective efficacy of anise in cerebral ischemia and reperfusion injury in rats. In this study, 28 Wistar Albino rats, weighing 250-300 grams (g), were used. Four groups were formed with 7 rats in each group. Group 1 (n=7): Control group, Group 2 (n=7): Anise group, 5 mL/kg/day of anise aqueous extract prepared according to Gamberini's protocol was given orally by gavage for 30 days. Group 3 (n=7): Cerebral ischemia reperfusion (CIR) group, at the beginning of the experiment, 30 minutes of cerebral ischemia and 1 hour of reperfusion were induced and the animals were sacrificed by exanguination. Group 4 (n=7): Anise+ CIR group, After administering 30 days of anise's aqueous extract, CIR was induced and the study was terminated. TOS values of the Anise+ CIR group was significantly lower than that of the CIR group (p<0.05). Il-6 and TNF-α values of the CIR group were significantly higher than the Anise+ CIR group (p<0,05). Our study revealed that anise ameliorates oxidative damage and inflammation due to cerebral ischemia/reperfusion, by reducing the levels of inflammatory cytokines (TNF-α, Il-6).

Effect of 2-methoxyestradiol nanoparticles combined with propofol on hippocampal nerve cells and metabolism after cerebral ischemia-reperfusion

Short-term or permanent reduction in cerebral blood flow can lead to cerebral ischemia, and if it persists, it can lead to necrosis and cell death. Reperfusion is restoration of blood supply, but it may further aggravate the damage of ischemic brain tissue. Propofol has characteristics such as rapid recovery, continuous infusion, and no accumulation. 2-Methoxyestradiol (2ME2) is a HIF-1-α inhibitor and reduces cell apoptosis. The brain ischemia-reperfusion hippocampal nerve cell model was in this study prepared in vitro. Samples were randomly assigned into control group (control), cerebral ischemia-reperfusion (CIR) group, propofol group (Propofol), 2ME2 nanoparticle group (2ME2-NPs), and combination group (Propofol+2ME2-NPs). The changes of cell proliferation and apoptosis activities were analyzed in each group, which included changes of Survivin expression, changes of intracellular Adenosine monophosphate, diphosphate, and triphosphate (AMP, ADP, and ATP, respectively) changes of malondialdehyde (MDA) and superoxide dismutase (SOD) Analysis also included secretion of IL-6 and TNF-α, and detection of HIF-1α and NF-κB expression. Results revealed that, CIR hippocampal nerve cell proliferation decreased, apoptosis activity increased, while Survivin expression increased. Moreover, ATP, ADP and AMP contents decreased, while secretion of inflammatory factors IL-6 and TNF-α increased, MDA increased, and SOD decreased. HIF-1α and NF-κB expressions increased. Propofol and 2ME2 nanoparticles promoted hippocampal neurons proliferation after CIR brain injury, inhibit the apoptotic activity, and reduce the expression of apoptotic protein Survivin. ATP, ADP and AMP content increased, IL-6 and TNF-α decreased, MDA decreased, SOD activity increased, HIF-1α and NF-κB decreased. The and combined group had a more significant effect. 2ME2 nanoparticles combined with propofol can inhibit HIF-1α and secretion of inflammatory factors by regulating oxidative stress and NF-κB signaling pathways, promoting the proliferation of hippocampal neurons, inhibiting apoptosis, and restoring cell energy and helping to restore nerve cell function.

Protective Effects of Sesamol on the Brains of Rats with Focal Cerebral Ischemia-Reperfusion Injury

Stroke is an acute cerebrovascular event associated with brain tissue injury, representing the most common cause of death. Thrombolysis and recanalization are the principal treatment modalities for ischemic stroke. Some patients experience cerebral ischemia-reperfusion injury following treatment. A previous study established that sesamol is effective in reducing risk factors for stroke. Here, we aimed to investigate the protective effect of sesame phenol on cerebral ischemia-reperfusion injury. A total of 72 SD rats were randomly divided into a sham group, cerebral ischemia-reperfusion (MCAO) group, cerebral ischemia-reperfusion with low dose sesame phenol (MCAO+sesamol A) group and cerebral ischemia-reperfusion with high dose sesame phenol (MCAO + sesamol B) group. After cerebral ischemia had been induced for 2h and reperfusion conducted for 24h, the volume of cerebral infarction, the degree of cerebral edema and the neurological deficit scores were tested. The results showed sesamin improved the neurological deficit score in a dose-dependent manner, reduced the volume of cerebral infarction, degree of cerebral edema. Prophylactic treatment with sesame phenol provided neuroprotective effects on cerebral ischemia-reperfusion injury.

Effect of matrine on JAK2/STAT3 signaling pathway and brain protection in rats with cerebral ischemia-reperfusion.

Ischemic encephalopathy is a common clinical disease. The main treatment goal is to achieve vascular recanalization. However, after vascular recanalization, the reperfusion of fresh blood can change local cell metabolism, thus adversely affecting cell structure and function, which can result in reperfusion injury. To explore the effect of matrine intervention of different concentrations on JAK2/STAT3 signaling pathway and brain protection in rats with cerebral ischemia-reperfusion. Healthy male Sprague Dawley rats were divided into a blank control group (20 rats), a model group (80 rats) and a sham group (20 rats). In the model group, the middle cerebral artery was occluded with suture method to establish cerebral ischemia-reperfusion model rats, which were subdivided into cerebral ischemia-reperfusion group, and 5, 10 and 20 mg/kg matrine groups, with 20 rats in each group. Indicators including neurological function score, brain infarct size, brain water content, lactic dehydrogenase activity, protein expressions of p-JAK2 and p-STAT3, as well as superoxide dismutase activity and malondialdehyde content were evaluated. Compared with cerebral ischemia-reperfusion group, all the indicators were significantly improved in the 3 matrine treatment groups in a dose-dependent manner, and protein expressions of p-JAK2 and p-STAT3 in the brain tissue and brain cell apoptosis rate were decreased with the increase of matrine concentration (all p < 0.05). Matrine can significantly ameliorate the neurological function and brain edema of rats with cerebral ischemia-reperfusion, and improve superoxide dismutase, malondialdehyde and lactic dehydrogenase levels in the brain tissue and brain cell apoptosis rate. The mechanism of matrine may be related to the inhibition of abnormal JAK2/STAT3 signaling pathway activation.

Sanhua Decoction, a Classic Herbal Prescription, Exerts Neuroprotection Through Regulating Phosphorylated Tau Level and Promoting Adult Endogenous Neurogenesis After Cerebral Ischemia/Reperfusion Injury.

Background: Ischemia stroke is the leading cause of death and long-term disability. Sanhua Decoction (SHD), a classic Chinese herbal prescription, has been used for ischemic stroke for about thousands of years. Here, we aim to investigate the neuroprotective effects of SHD on cerebral ischemia/reperfusion (CIR) injury rat models.Methods: The male Sprague-Dawley rats (body weight, 250–280 g; age, 7–8 weeks) were randomly divided into sham group, CIR group, and SHD group and were further divided into subgroups according to different time points at 6 h, 1, 3, 7, 14, 21, and 28 d, respectively. The SHD group received intragastric administration of SHD at 10 g kg−1 d−1. The focal CIR models were induced by middle cerebral artery occlusion according to Longa’s method, while sham group had the same operation without suture insertion. Neurological deficit score (NDS) was evaluated using the Longa’s scale. BrdU, doublecortin (DCX), and glial fibrillary acidic protein (GFAP) were used to label proliferation, migration, and differentiation of nerve cells before being observed by immunofluorescence. The expression of reelin, total tau (t-tau), and phosphorylated tau (p-tau) were evaluated by western blot and RT-qPCR.Results: SHD can significantly improve NDS at 1, 3, 7, and 14 d (p < 0.05), increase the number of BrdU positive and BrdU/DCX positive cells in subventricular zone at 3, 7, and 14 d (p < 0.05), upregulate BrdU/GFAP positive cells in the ischemic penumbra at 28 d after CIR (p < 0.05), and reduce p-tau level at 1, 3, 7, and 14 d (p < 0.05). There was no significant difference on reelin and t-tau level between three groups at each time points after CIR.Conclusions: SHD exerts neuroprotection probably by regulating p-tau level and promoting the proliferation, migration, and differentiation of endogenous neural stem cells, accompanying with neurobehavioral recovery.

Sevoflurane Post-treatment Upregulated miR-203 Expression to Attenuate Cerebral Ischemia-Reperfusion-Induced Neuroinflammation by Targeting MyD88.

To investigate the expression of miR-203 by sevoflurane treatment and its effect on neuroinflammation induced by cerebral ischemia-reperfusion. Rats were randomly divided into sham operation group (C), cerebral ischemia-reperfusion group (I/R), and sevoflurane treatment group (S). The neurological function score was evaluated. The area of cerebral infarction was evaluated by TTC staining. The expression of inflammatory factor in brain tissue was detected by ELISA. The apoptosis of neurons was detected by TUNEL. A miR-203 agonist and inhibitor treated the cerebral ischemia-reperfusion model. The luciferase assay verified whether miR-203 targeted MyD88. To further verify the relationship between miR-203 and MyD88, the I/R group was treated with MyD88 activator and inhibitor, and the mRNA expressions of miR-203 and MyD88 in brain tissue were detected by RT-PCR. Western blot was used to detect the expression of MyD88 protein in brain tissue, and the above experiment was repeated. Compared with the I/R group, miR-203 mRNA was significantly increased in brain tissue and the neurological function score, the area of cerebral infarction, the expression of inflammatory factor, and MyD88 mRNA were decreased in the S group (P < 0.05). After treatment of miR-203 agonist and inhibitor in the I/R group, overexpression of miR-203 could alleviate cerebral ischemia-reperfusion injury, and miR-203 inhibitor could aggravate cerebral ischemia-reperfusion injury. The miR-203 agonist could enhance the action of sevoflurane, and the miR-203 inhibitor could reverse the action of sevoflurane. miR-203 agonist treatment could inhibit the expression of MyD88 gene and protein and reduce the neuroinflammation induced by cerebral ischemia-reperfusion. The treatment of sevoflurane upregulated miR-203 expression, which targeted MyD88 and attenuate neuroinflammation induced by cerebral ischemia-reperfusion.

Imaging Analysis and Evaluation of Neural Stem Cell Intracerebral Migration and Functional Reconstruction Based on Deep Learning

Neural stem cell is a type of stem cell with self-renewal ability and multi-directional differentiation potential. Under certain conditions, neural stem cells can differentiate into neurons, oligodendrocytes, and astrocytes, thereby participating in the occurrence of the nervous system. Considering that deep convolutional neural networks have better feature learning capabilities for image data than feedforward neural networks, this paper studies how to apply deep convolutional neural networks to modeling based on imaging features, and constructs convolutional neural networks. In this paper, the distribution of CD133+ neural stem cells in different neuroanatomical regions of rat brain and possible migration flow were studied. The experimental results show that there are obvious differences in the distribution of neural stem cells in different neuroanatomical regions. With the growth and development of rats, a large number of CD133+ neural stem cells migrate from the subventricular zone to the surrounding ganglia, corpus callosum, and cerebral cortex. Seven days before the operation, the rats were trained in water maze, and the EL (Escape Latency) of the rats was recorded for 1 week, 2 weeks and 1 month. Compared with the control group of sham operation, EL was significantly increased in the cerebral ischemia-reperfusion group. Compared with cerebral ischemia-reperfusion + acupuncture group and cerebral ischemia-reperfusion group, EL was significantly smaller. The results show that electroacupuncture can induce the proliferation of newborn cells in the brain and promote the differentiation of newborn cells into glial cells and nerve cells. After electroacupuncture intervention, a small number of new nerve cells already have the activity and function of secreting Ach. Electroacupuncture intervention can promote the recovery of rat nerve function after cerebral ischemia and reperfusion.

Effect of Different Exercise Intensity Preconditioning on Global Ischemia-Induced Neuronal Death and Expression of Gadd45β and DNA-PKcs in Rats

<i>Background</i> Acute ischemic stroke causes long-term neurological and neurobehavioral dysfunctions. With the development of clinical medicine, the importance of pre-ischemic exercise intervention has been gradually recognized, but its mechanism remains to be further explored. <i>Objective</i> This study investigates the effects of different exercise intensity preconditioning in changes of hippocampal neurons and the expression of Gadd45β and DNA-PKcs in the hippocampal region after cerebral ischemia-reperfusion in rats. <i>Method</i> 160 SD rats were divided into control group (n=40), cerebral ischemia reperfusion group (I/R group, n=40), middle intensity exercise preconditioning group (EI 1+I/R group, n=40), high intense exercise preconditioning group (EI 2+I/R group, n=40). Stroke was induced by improved Pulsinelli four blood vessel blocking after exercise preconditioning. Morphological changes of neurons in the hippocampal region of rats were observed by HE staining at 6 h, 1d, 3d and 7d after ischemia in each group. Immunohistochemistry method was used to detect the expression of Gadd45β and DNA-PKcs in hippocampus CA1. The mRNA level of Gadd45β and DNA-PKcs in hippocampal CA1 was detected by Real Time PCR. <i>Results</i> Compared with I/R group, the neuronal cell necrosis of was alleviated in EI 1+I/R group, but more serious in EI 2+I/R group; The expression of Gadd45β and DNA-PKcs were significantly higher in the EI 1+ I/R group, but lower in EI 2+I/R group (<i>P</i><0.01). <i>Conclusion</i> Moderate intensity exercise preconditioning can improve the survival of neurons after cerebral ischemia-reperfusion injury in rats. However, high-intensity motor preconditioning increased the damage and loss of neurons, and its mechanism may be related to the regulation of the expression of Gadd45β and DNA-PKcs in the hippocampus of cerebral ischemia-reperfusion rats, thus protecting and promoting the function of DNA repair system.

Influence of miR-34a on cerebral neuronal apoptosis in rats with cerebral ischemia reperfusion through the Notch1 signaling pathway.

To explore the influence and the underlying mechanism of micro-ribonucleic acid (miR)-34a on cerebral neuronal apoptosis in rats with cerebral ischemia-reperfusion (CIR). 60 adult male Wistar rats were randomly divided into 3 groups: Sham group, CIR group and miR-34a knockdown group. The rat model of CIR was established using the suture occlusion method. The expression level of miR-34a in lesion tissues in the three groups was determined via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). The pathological injury of brain tissues was detected via hematoxylin-eosin (HE) staining and the infarction region in each group was evaluated via triphenyl tetrazolium chloride (TTC) staining. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining was performed to measure the cerebral neuronal apoptosis level. The level of Nissl's body in each group was detected via Nissl's staining. The expression level of the platelet-derived neurotrophic factor (PDNF) and Notch1/hypoxia-inducible factor-1α (HIF-1α) signaling pathway-related proteins in brain tissues were detected via immunohistochemistry and Western blotting, respectively. The expression level of miR-34a in brain tissues of the CIR group was significantly increased compared to that of the Sham group (p < 0.05). After the intervention with miR-34a, the infarction area of brain tissues was markedly reduced when comparing to the CIR group (p < 0.05). In addition, the results of HE staining and Nissl staining revealed that CIR treatment led to edema in cerebral neurons, disorderly arranged neurons, and remarkably decreased number of Nissl's bodies. However, miR-34a knockdown following CIR significantly alleviated the brain tissue injury and markedly increased the number of Nissl's bodies (p < 0.05). The results of TUNEL staining also indicated that miR-34a siRNA could remarkably reverse the cerebral neuronal apoptosis caused by CIR in rats (p < 0.05). According to the immunohistochemical staining results, the expression of PDNF in brain tissues declined in the CIR group, while enhanced in the miR-34a siRNA group (p < 0.05). Furthermore, the Western blotting results manifested that miR-34a siRNA could up-regulate the Notch1 and HIF-1α protein expressions in brain tissues of CIR rats. Our data demonstrated that the miR-34a knockdown could alleviate the brain tissue injury and neuronal apoptosis by activating the Notch1/HIF-1α signaling pathway CIR-treated rats.

Effects of Lipoxin A4 Pretreatment on Cognitive Function of Aged Rats after Global Cerebral Ischemia Reperfusion.

The aim of the present study was to investigate the effect of lipoxin A4 (LXA4) pretreatment on cognitive function of aged rats after global cerebral ischemia reperfusion, and to explore its possible mechanism. Thirty-six aged male Sprague-Dawley rats were randomly divided into three groups (n=2 each): sham-operation group (S group), global cerebral ischemia reperfusion group (I/R group) and LXA4-pretreatment group (L group). The rat model of global cerebral ischemia reperfüsion was established by occlusion of the bilateral common carotid artery with hypotension. The cognitive function of rats was determined by a step-down type passive avoidance test and Morris Water Maze test on the third day after reperfUsion. Rats were sacrificed after Water Maze test and the pathological changes of hippocampal CAI region were observed and the related inflammatory mediators were determined. As compared with S group, the escape latency in I/R group was prolonged from the first day to the fifth day, while that in L group was prolonged from the first day to the third day. The retention time in I/R group and L group in the first quadrant was shortened. The reaction time, frequency of reaction mistake and frequency of escape mistake in I/R group increased, and the latent period shortened. The frequency of escape mistake in L group increased, and the damage in the hippocampal CAI region of I/R group and L group was obvious. The levels of S-100β, TNP-α, IL-lβ, IL-10 and NF-κB in I/R group and L group increased. As compared with I/R group, the escape latency in L group was shortened from the first day to the fifth day, and the retention time in the first quadrant prolonged. The reaction time, frequency of reaction mistake and frequency of escape mistake in L group decreased, and the latent period prolonged. The damage in the hippocampal CAI region of L group was alleviated as well. The levels of S-100β, TNP-α, IL-lβ and NF-κB in L group decreased, and those of IL-10 increased. It can be concluded that LXA4 pretreatment can improve the cognitive function in aged rats after global cerebral ischemia reperfusion probably by inhibiting the inflammatory reaction.

MiR-125b blocks Bax/Cytochrome C/Caspase-3 apoptotic signaling pathway in rat models of cerebral ischemia-reperfusion injury by targeting p53

ABSTRACTObjective: To explore the potential effect of miR-125b on p53-mediated regulation of Bax/Cytochrome C/Caspase-3 apoptotic signaling pathway in rats with cerebral ischemia-reperfusion (CIR) injury.Methods: Sprague-Dawley (SD) rats were used to conduct CIR injury and injected with miR-125b mimic/inhibitor or p53 inhibitor (Pifithrin-α, PFT-α). Dual-luciferase reporter gene assay was used to analyze the targeting relationship between miR-125b and p53. Longa scoring and Triphenyl tetrazolinm chloride (TTC) staining were used to test the neurologic function and determine infarct size, respectively. Hematoxylin-eosin (HE) and Nissl’s stainings were conducted to observe the morphology of cortical neurons. Neuronal nuclei (NeuN) expression was detected by immunohistochemical staining. QRT-PCR was performed to detect the expressions of miR-125b and p53. TUNEL staining and Western blotting was used to determine neuronal apoptosis and expressions of Bax/Cytochrome C/Caspase-3 signaling pathway-related proteins, respectively.Results: Our results showed that miR-125b could directly target p53. As observed, overexpression of miR-125b could obviously reduce the neurological score, infarct size, and brain water content after CIR in rats, which also improved the morphology of cortical neurons, increased the number of neurons, reduced neuronal apoptosis, and inhibited the expressions of Bax/Cytochrome C/Caspase-3 pathway. Moreover,the similar results were observed in rats with CIR after injected with PFT-α. But no significant differences in each index were found in CIR group and CIR + anti-miR-125b + PFT-α group.Conclusion: MiR-125b exerts protective effects on CIR injury through inhibition of Bax/Cytochrome C/Caspase-3signaling pathway via targeting p53, which is likely to be a promising treatment for CIR.Abbreviations: 3’–UTR: 3–untranslated region; CIR: cerebral ischemia–reperfusion; CIS: cerebral ischemic stroke; PFT–α: Pifithrin–α; PVDF: polyvinylidene fluoride; SD: Sprague–Dawley; TBST: tris buffered saline with tween. TTC staining: Triphenyl tetrazolinm chloride staining; TUNEL: Terminal deoxynucleotidyl transferase–mediated dUTP–biotin nick end labeling.

Effect of inhibition of P38MAPK phosphorylation on learning and memory and autophagy in hippocampus of rats after cerebral ischemic postconditioning

Objective To investigate the effect of ischemic postconditioning on autophagy and learning and memory impairment in rats with ischemia-reperfusion injury by P38MAPK. Methods Ninty-six rats were randomly divided into sham group (Sham group), cerebral ischemia reperfusion group (CIR group), cerebral ischemic postconditioning group (CIP group) and cerebral ischemic postconditioning combined with SB203580 group (CIP + SB203580 group), and 24 rats in each group. The rat model of cerebral ischemia was established by Pulsinelli four-vessel occlusion. The learning and memory abilities of rats were measured by Morris water maze. HE staining were used to detect the morphological changes of hippocampal neurons. The phosphorylation of P38MAPK and Beclin-1, LC3-Ⅱexpression were observed by immunohistochemistry. Results Compared with the Sham group, the number of crossing the platform decreased(24 h: (3.04±0.20)times), and the escape latency was longer in CIR group(24 h: (58.38±1.52) s) (all P<0.05). The number of survival neurons reduced (24 h: 70.93±1.86), and the expression of P38MAPK, LC3-II, Beclin-1 in immunohistochemistry were increased in CIR group(all P<0.05). Compared with CIR group, the number of crossing the platform at each time point increased (24 h: (5.46±0.50)times), the escape latency was shorter (24 h: (52.42±1.53)s), the number of survival neurons increased at each time point(24 h: (83.07±5.30)) and the expression level of P38MAPK decreased in the CIP group, while the expression level of LC3-II, Beclin-1 increased (all P<0.05). Compared with the CIP group, the number of crossing the platform((24 h: (7.13±0.33)times), the escape latency was shorter (24 h: (48.04±1.39)s), the number of survival neurons increased at each time point(24 h: (91.40±1.74)), and the expression of P38MAPK was down-regulated, while the expression of LC3-II, Beclin-1 were up-regulated in CIP + SB203580 group(all P<0.05). Conclusion Ischemic postconditioning can improve learning and memory impairment in rats with ischemia-reperfusion injury by P38MAPK regulating autophagy. Key words: P38MAPK; Ischemic postconditioning; Learning and memory; Autophagy; Rat

The role of mTOR signaling pathway on cognitive functions in cerebral ischemia-reperfusion.

The role and mechanism of the mTOR signaling pathway in the impaired cognitive function in cerebral ischemia-reperfusion were examined in the present study. Sprague-Dawley (SD) rats were divided into the sham operation, cerebral ischemia, cerebral ischemia-reperfusion and cerebral ischemia-reperfusion adaptive groups. A Morris water maze test was carried out in the different treatment groups at 2 weeks after surgery to detect cognitive function. After the experimental animals were sacrificed, fluorescent quantitative PCR test was used to detect the key signaling molecules in the mTOR signaling pathway in the different treatment groups, such as mTOR, p-mTOR, AKT and p-AKT gene mRNA expression. The protein expression was determined by enzyme-linked immunosorbent assay and western blotting. mTOR expression and localization in the different treatment groups was detected by immunohistochemistry, and the positive cell rate was determined. Compared with the sham operation group, the levels of mTOR, p-mTOR, AKT and p-AKT mRNAs and hippocampal proteins were significantly lower in the cerebral ischemia group and cerebral ischemia-reperfusion group (P<0.05). Levels of mTOR, p-mTOR, AKT and p-AKT mRNAs and proteins in the cerebral ischemia-reperfusion adaptive group decreased but did not show significant differences (P>0.05). The Morris water maze results showed that, the adaptive ability and the cognitive functions were improved significantly in the cerebral ischemia-reperfusion adaptive group when compared with the cerebral ischemia and cerebral ischemia-reperfusion groups (P<0.05). The number of mTOR-positive cells in hippocampus was significantly higher in the sham operation and cerebral ischemia-reperfusion adaptive groups, but there was no difference between these groups. In conclusion, mTOR signaling pathway improves the cognitive function in cerebral ischemia-reperfusion in rats.

Electro-acupuncture ameliorates cognitive impairment via improvement of brain-derived neurotropic factor-mediated hippocampal synaptic plasticity in cerebral ischemia-reperfusion injured rats.

A previous study by our group found that electro-acupuncture (EA) at the Shenting (DU24) and Baihui (DU20) acupoints ameliorates cognitive impairment in rats with cerebral ischemia-reperfusion (I/R) injury. However, the precise mechanism of action has remained largely unknown. The present study investigated whether brain-derived neurotropic factor (BDNF) mediates hippocampal synaptic plasticity as the underlying mechanism. Rats were randomly divided into three groups: The sham operation control (Sham) group, the focal cerebral ischemia-reperfusion (I/R) group, and the I/R with EA treatment (I/R+EA) group. The I/R+EA group received EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints after the operation. EA treatment was found to ameliorate neurological deficits (P<0.05) and reduce the cerebral infarct volume (P<0.01). In addition, EA improved cognitive function in cerebral I/R-injured rats (P<0.05). Furthermore, EA treatment promoted synaptic plasticity. Simultaneously, EA increased the hippocampal expression of BDNF, its high-affinity tropomyosin receptor kinase B (TrkB) and post-synaptic density protein-95 (PSD-95) in the rats with cerebral I/R injury. Collectively, the findings suggested that BDNF-mediated hippocampal synaptic plasticity may be one mechanism via which EA treatment at the Shenting (DU24) and Baihui (DU20) acupoints improves cognitive function in cerebral I/R injured rats.

Effect of electroacupuncture on gene expression in calcium signaling pathway in hippocampal cells in mice with cerebral ischemia reperfusion

ObjectiveTo observe the regulation of electroacupuncture on gene expression at calcium signaling pathways in mice with cerebral ischemia reperfusion. MethodsSixty male, inbred Kunming mice were randomly assigned to three groups: repeated cerebral ischemia reperfusion group (RG, n = 24), sham-operated group (SG, n = 12), and electroacupuncture group (EG, n = 24). Mice in RG and EG groups were modeled by repeated cerebral ischemia reperfusion surgery, and EG mice were treated with electroacupuncture for 30 min after recovery from anesthesia. Changes in gene expression profile of mice hippocampi were analyzed by global expression profile microarray. Genes that were up-regulated or down-regulated greater than 1.5 folds were considered to be biologically meaningful. Real-time quantitative polymerase chain reaction (q-PCR) method was used to verify the expression of selected genes based on the algorithm [2^ (‡‡Ct)]. ResultsCompared with SG mice, 242 genes showed different in expressions in RG mice: 107 down-regulated and 135 up-regulated. Compared with RG mice, 609 genes showed a difference of expression in EG mice: 315 down-regulated and 375 up-regulated. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated two pathways: calcium signaling and long-term potentiation in which 11 differentially expressed genes selected. Six of the 11 genes in the calcium signaling pathway were verified after real-time q-PCR testing. ConclusionElectroacupuncture treatment of cerebral ischemia reperfusion appears to regulate Atp2a2, Cacna1e, Camk2a, Gnas, Grm1, Rapgef3 genes in the calcium signaling pathway.

MTOR/autophagy pathway in the hippocampus of rats suffering intermittent hypoxia preconditioning and global cerebral ischemia-reperfusion.

We explored the role of mTOR/autophagy pathway in the aggravation of cerebral ischemia-reperfusion nerve injury caused by intermittent hypoxia. Eighty male wistar rats were divided into four groups by the random number method: sham operation group (SO group, n=20), cerebral ischemia-reperfusion group (I/R group, n=20), intermittent hypoxia and cerebral ischemia-reperfusion group (IH+I/R group, n=20), intermittent hypoxia and cerebral ischemia-reperfusion group plus mTOR inhibitor group (inhibitor group, n=20). The results showed that compared with the SO group, HE staining showed structural damage of neurons at each time point, the immunohistochemical assay showed an increasing number of mTOR and beclin1 immune-positive cells (P<0.05) and RT-PCR showed enhanced expression of mTOR and beclin1 protein in the I/R group (P<0.05). Compared with the I/R group, HE staining showed exacerbating structural damage of neurons at each time point, the immunohistochemical assay showed an increasing number of mTOR and beclin1 immune-positive cells (P<0.05) and RT-PCR showed enhanced expression of mTOR and beclin1 protein in the IH+I/R group (P<0.05). Compared with the IH+I/R group, HE staining showed remissive structural damage of neurons at each time point, the immunohistochemical assay showed a decreasing number of mTOR immune-positive cells and a rising number of beclin1immune-positive cells (P<0.05) and RT-PCR showed weakened expression of mTOR protein and enhanced expression of beclin1 protein in the inhibitor group (P<0.05). Thence, the present study indicated that intermittent hypoxia preconditioning can aggravate the nerve injury of the global cerebral ischemia-reperfusion model, and the mechanism is associated with the activation of mTOR/autophagy pathway.

Effect of exercise preconditioning on nerve growth factor and learning-and-memory abilities in rats suffered from focal cerebral ischemia

Objective To investigate the effect of exercise preconditioning on the expression of nerve growth factor(NGF) and its receptor TrkA as well as learning-and-memory abilities in rats suffered from focal cerebral ischemia. Methods Thirty-six male SD rats were randomly divided into sham operation group (Sham-MCAO, n=12), focal cerebral ischemia-reperfusion group (MCAO, n=12) and exercise preconditioning + cerebral ischemia-reperfusion group (EX+ MCAO, n=12). Rats in EX+ MCAO group were placed in the treadmill device and accepted 4 weeks exercise training. Then method of middle cerebral artery occlusion was applied to prepare transient focal cerebral ischemia reperfusion model. Garcia’s method was used to assess the neural function in rats. Western blotting was applied to test the expression of NGF and TrkA protein in the successfully established experimental MCAO rats. Morris water maze experiment was utilized to test the learning-and-memory abilities of the rats. Results (1)Compared with Sham-MCAO group, the expression of NGF in rats’ brain tissue was lower in MCAO group (cerebral ischemia 1h reperfusion 24h) (P 0.05). Conclusion Exercise preconditioning can up-regulate the expressions of NGF and TrkA protein, which can also improve the learning-and-memory abilities in rats suffered from focal cerebral ischemia reperfusion injury. Key words: Exercise preconditioning; NFG; TrkA; Focal cerebral ischemia reperfusion; Learning and memory

Mechanism of low molecular weight GTP binding protein RAC1 in injury of neural function of rats with cerebral ischemia reperfusion.

To discuss the mechanism of low molecular weight GTP binding protein RAC1 in the injury of neural function based on building the rat model of cerebral ischemia reperfusion. Middle cerebral artery of rats was ligated and the ligature was released to restore the perfusion after 2h, the rat model of cerebral ischemia reperfusion injury was built, while the middle cerebral artery was ligated. The rats were randomly divided into the sham group, cerebral ischemia reperfusion group (I/R group) and the group with the injection of RAC1 activity inhibitor NSC23766 (NSC group). The survival and neurological severity score of rats in each group were observed and recorded. Nissl staining was employed to observe the nerve cells, and Western blot to detect expression of RAC1, superoxide dismutase and malondialdehyde. Number of nerve cells for rats in NSC group was significantly more than that in I/R group, but significantly less than that in sham group, with the statistical difference (P<0.05). The brain water content for rats in NSC group was significantly lower than that in I/R group, but significantly higher than that in sham group, with the statistical difference (P<0.05). The expression of RAC1 and malondialdehyde for rats in NSC group was significantly lower than that in I/R group, but higher than that in sham group; while the expression of superoxide dismutase was lower than that in sham group, but higher than that in I/R group, with the statistical difference (P<0.05). The inhibition of RAC1 activity can reduce the oxidative stress, reduce the neurologic impairment because of cerebral ischemia reperfusion and thus protect the neural function.

The expressions of Caspase-9 and heat-shock protein-90 after focal cerebral ischemia-reperfusion injury in rats

Objective To investigate the expression of Caspase-9 and heat-shock protein-90 (HSP 90) in rats after focal cerebral ischemia-reperfusion injury. Methods The male SD rats (200-250 g) were divided into three groups by the random number table: normal group, sham group and cerebral ischemia-reperfusion (CIR) group. Each group was sorted into four subgroups including group 6 h, group 24 h, group 48 h and group 72 h according to the reperfusion time. Suture-occluded method was adopted to prepare focal cerebral ischemia-reperfusion(CIR) injury in rat model. Enzyme-linked immunosorbent assay (ELISA) method was used to detect the variations of Caspase-9 and HSP-90 expression in rats. Results The changes in Caspase-9 and HSP 90 expression in the brain cells were observed by ELISA method. The expression of Caspase-9 and HSP-90 was weakly expressed in sham group, and was at peak in CIR group within 24 h-48 h, then began to decline at 72 h after the reperfusion time. The differences in the expression of caspase-9 and HSP-70 between sham group and normal group were not statistically significant. Conclusions Apoptotic cells gradually increase along with reperfusion time and reach the peak at 48 h after cerebral ischemia-reperfusion. In ischemia half dark stripe, the expression of Caspase-9 and HSP 90 is increased in neuronal cells after cerebral ischemia-reperfusion, and the positive cells number is at peak at 48 h after cerebral ischemia-reperfusion. Apoptosis of neuronal cells after cerebral ischemia and reperfusion is a dynamic evolutionary process. The expression of Caspase-9 and HSP 90 in nerve cells plays an important role in regulating cell apoptosis. Key words: Reperfusion injury; Caspase-9; Heat-shock proteins