Middle Cerebral Artery Ischemia-reperfusion Research Articles

Electroacupuncture improves cognitive impairment after ischemic stroke based on regulation of mitochondrial dynamics through SIRT1/PGC-1α pathway

In recent years, the mechanism of acupuncture in the treatment of post-stroke cognitive impairment (PSCI) has not been fully elucidated. The balance between mitochondrial fission and fusion is important for PSCI. Our previous research demonstrated that electroacupuncture can improve learning and memory in middle cerebral artery ischemia reperfusion (MCAO/R) rats. However, the specific mechanism by which electroacupuncture improves learning and memory in MCAO/R rats by regulating mitochondrial fission and fusion needs to be further investigated. The MCAO/R rats was developed using the line-bolt method. The rats were randomly divided into sham-operated (Sham), model (MCAO/R), electroacupuncture (MCAO/R + EA) and sham-electroacupuncture (MCAO/R + sham EA) groups. Investigating the effects of EA on the expression of Sirtuin1 (SIRT1), peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), Optic atrophy 1R + (OPA1) and Dynamin-related protein 1 (DRP1) in hippocampal neurons and on the morphology and function of hippocampal neurons and mitochondria. EA was able to reduce neurologic deficit scores and cerebral infarct volume and improve new object discrimination in MCAO/R rats, but there were no significant changes in these indices in the sham-electroacupuncture group. Moreover, EA increased the expression of SIRT1, PGC-1α, and OPA1 in hippocampal tissues, inhibited the expression of DRP1, attenuated neuronal and mitochondrial damage, and reduced mitochondrial fragmentation. The mechanism by which EA improves learning memory deficits in MCAO/R rats may be related to the inhibition of SIRT1/PGC-1α expression, the enhancement of mitochondrial fusion and the obstruction of its fission, and the reduction of hippocampal neuronal damage.

Thymoquinone regulates microglial M1/M2 polarization after cerebral ischemia-reperfusion injury via the TLR4 signaling pathway

Acute ischemic stroke followed by microglia activation, and the regulation of neuroinflammatory responses after ischemic injury involves microglia polarization. microglia polarization is involved in the regulation of neuroinflammatory responses and ischemic stroke-related brain damage. Thymoquinone (TQ) is an anti-inflammatory agent following ischemic stroke onset. However, the significance of TQ in microglia polarization following acute ischemic stroke is still unclear. We predicted that TQ might have neuroprotective properties by modulating microglia polarization. In this work, we mimicked the clinical signs of acute ischemic stroke using a mouse middle cerebral artery ischemia-reperfusion (I/R) model. It was discovered that TQ treatment decreased I/R-induced infarct volume, cerebral oedema, and promoted neuronal survival, as well as improved the histopathological changes of brain tissue. The sensorimotor function was assessed by the Garica score, foot fault test, and corner test, and it was found that TQ could improve the motor deficits caused by I/R. Secondly, real-time fluorescence quantitative PCR, immuno-fluorescence, ELISA, and western blot were used to detect the expression of M1/M2-specific markers in microglia to explore the role of TQ in the modulation of microglial cell polarization after cerebral ischemia-reperfusion. We found that TQ was able to promote the polarization of microglia with extremely secreted inflammatory factors from M1 type to M2 type. Furthermore, TQ could block the TLR4/NF-κB signaling pathway via Hif-1α activation which subsequently may attenuate microglia differentiation following the cerebral ischemia, establishing a mechanism for the TQ's beneficial effects in the cerebral ischemia-reperfusion model.

Function and mechanism of the human SOD2 gene in mice cerebral ischemia/ reperfusion injury.

To investigate the neuroprotective effects of the SOD2 gene in cerebral ischemia reperfusion injury function and the underlying mechanisms in a mice model of middle cerebral artery ischemia reperfusion. SOD2 transgenic mice were engineered using transcription activator-like effector nucleases, and the genotype was identified using PCR after every three generations. Transgenic and C57BL/6J wild type mice were simultaneously subjected to the middle cerebral artery occlusion model. SOD2 expression in the brain, heart, kidney, and skeletal muscle of transgenic mice was significantly higher than that in the wild type. Following ischemia reperfusion, the infarct volume of wild type mice decreased after treatment with fenofibrate compared to the CMC group. Infarction volume in SOD2 transgenic mice after CMC and fenofibrate treatment was significantly reduced. The recovery of cerebral blood flow in wild type mice treated with fenofibrate was significantly enhanced compared with that in the CMC group. The expression of SOD2 in transgenic mice was significantly higher than that in wild type mice, the neuroprotective role of fenofibrate depends on an increase in SOD2 expression.

Analgecine protects against cerebral ischemia-reperfusion through apoptosis inhibition and anti-neuroinflammation in rats

Stroke influence the quality of life of patients and leave big public health issues as acute cerebrovascular disease all over the world. Analgecine (AGC) relieves pain and accelerates repair of nerve injury. This current study aims to observe the pharmacological effects and related mechanisms of AGC in cerebral ischemic stroke among middle cerebral artery ischemia-reperfusion (MCAO) rats. After seven days of AGC administration, motor function was enhanced as evidenced by the prehensile traction test. Morphological ameliorations were observed by immunohistochemistry analysis. The protein expression levels of HSP70, Bcl-2, Bax, TRAF-6, MyD88, BDNF, NGF, pCREB, CREB, pTrkB, TrkB, pAKT and AKT were estimated by western blot. Meanwhile, AGC alleviated MCAO-induced inflammation chiefly by decreasing inflammatory cytokines in rat brain tissues. These results above suggested that MCAO-caused brain infarction was obviously alleviated by AGC. The immunohistochemistry data showed that AGC reduced neuronal injury and apoptosis, and inhibited microglia and astrocytes activation. The protein results suggested the expression of apoptosis-relevant proteins decreased among AGC treated groups and the neurotrophin related proteins were obviously enhanced by CREB/BDNF/TrkB/AKT and HSP70/Bcl-2/Bax pathways. Collectively, the results demonstrated that AGC primarily promoted neuro-nutrition, reduced the injury of nerve apoptosis and ameliorated neuroinflammation. In summary, AGC played a neuroprotective role, which had provided reliable evidence for AGC to be a potential drug in treating stroke.

Effect of butylphthalide on VEGF and Ang-1 levels of cerebra and serum in rats with middle cerebral artery ischemia-reperfusion

Objective To explore the effect of butylphthalide on the vascular endothelia growth factor(VEGF) and amgiopoietin-1(Ang-1) levels in cerebra and serum of rats with middle cerebral artery ischemia-reperfusion. Methods 39 male SD rats were randomly divided into sham operation group, ischemia-reperfusion group and butylphthalide- pretreated group with 13 rats in each group. The cerebral ischemia-reperfusion rat model was established in ischemia-reperfusion group and butylphthalide-pretreated group. 24 hours after reperfusion, the brain and serum were collected to detect VEGF and Ang-1 levels using ELISA and immunohistochemistry. The cerebral capillary endothelial morphology was observed with the electron microscope. Results The cell edema and impaired ultrastructure of cerebral capillary endothelial in butylphthalide-pretreated group were reduced compared with ischemia-reperfusion group. The VEGF and Ang-1 levels of cerebra(VEGF: (0.119±0.017) vs (0.100±0.016), Ang-1: (0.120±0.023) vs (0.097±0.018)) and serum (VEGF: (45.51±22.4) pg/ml vs (20.45±6.14) pg/ml, Ang-1: (126.32±61.89) ng/ml vs (70.02±20.80) ng/ml) were higher in ischemia-reperfusion group compared with sham operation group (P<0.05), while butylphthalide-pretreated rats displayed the higher VEGF (Cerebra: (0.137±0.022) vs (0.119±0.017), Serum: (80.46±13.65) pg/ml vs (45.51±22.4)pg/ml) and Ang-1 (Cerebra: (0.142±0.020) vs (0.120±0.023), Serum: (181.49±49.45) ng/ml vs (126.32±61.89) ng/ml) expression compared with ischemia-reperfusion rats (P<0.05). Conclusion Butylphthalide can protect the brain capillary endothelial cells in rats with middle cerebral artery ischemia-reperfusion, and upregulate production of VEGF and Ang-1. Key words: Butylphthalide; Cerebral ischemia reperfusion; Endothelium; VEGF; Ang-1

Exacerbated venous thromboembolism in mice carrying a protein S K196E mutation

AbstractProtein S (PS) acts as an anticoagulant cofactor for activated protein C in regulation of blood coagulation. The K196E mutation in PS is a race-specific genetic risk factor for venous thromboembolism with a prevalence of ∼2% within the Japanese population. To evaluate the thrombosis risk of the PS-K196E mutation, we generated PS-K196E knockin mice and heterozygous PS-deficient mice. We analyzed their thrombotic states, comparing with mice carrying the factor V Leiden mutation (FV-R504Q), a race-specific genetic risk for venous thrombosis in whites. PS-K196E mice grew normally but had decreased activated protein C cofactor activity in plasma. Purified recombinant murine PS-K196E showed the same decreased activated protein C cofactor activity. A deep vein thrombosis model of electrolytic inferior vena cava injury and pulmonary embolism models induced by infusion of tissue factor or polyphosphates revealed that PS-K196E mice, heterozygous PS-deficient mice, and FV-R504Q mice were much more susceptible to venous thrombosis compared with wild-type mice. Transient middle cerebral artery ischemia-reperfusion injury model studies demonstrated that both PS-K196E mice and heterozygous PS-deficient mice had cerebral infarction similar to wild-type mice, consistent with human observations. Our in vitro and in vivo results support a causal relationship between the PS-K196E mutation and venous thrombosis and indicate that PS-K196E mice can provide an in vivo evaluation system to help uncovering racial differences in thrombotic diseases.

Effect of butylphthalide on VCAM-1 and ICAM-1 in rats with middle cerebral artery ischemia-reperfusion

Objective To explore the effect of butylphthalide on vascular cell adhesion molecule-1(VCAM-1) and intercellular adhesion molecule-1(ICAM-1) in rats with middle cerebral artery ischemia-reperfusion. Methods 30 male SD rats were randomly divided into sham operation group(n=10), the model group(n=10) and butylphthalide pretreated group(n=10). Rat model of cerebral ischemia and reperfusion was established using the cerebral artery occlusion method.The brain expression of VCAM-1 and ICAM-1 was detected by immunohistochemistry. The serum VCAM-1 and ICAM-1 levels were detected using Enzyme-linked immunosorbent assay (ELISA). Results The VCAM-1 and ICAM-1 levels of brain and serum in the model group were higher than those of sham operation group (P 0.05), while VCAM-1 expression was higher in butylphthalide pretreatment group compared with the model group (brain: (0.127±0.017)ng/ml vs(0.164±0.025)ng/ml; serum: (160.22±53.95)ng/ml vs (270.89±76.49)ng/ml, all P<0.05). Conclusion Butylphthalide can inhibit the VCAM-1 level of brain and serum in rat with middle cerebral artery ischemia-reperfusion. Key words: Butylphthalide; Middle cerebral artery ischemia-reperfusion; Vascular cell adhesion molecule-1; Intercellular adhesion molecule-1

Variation of pathways and network profiles reveals the differential pharmacological mechanisms of each effective component to treat middle cerebral artery ischemia-reperfusion mice.

Using a system pharmacology strategy, this study evaluated the unique pharmacological characteristics of three different neuroprotective compounds for the treatment of cerebral ischemia-reperfusion. A microarray including 374 brain ischemia-related genes was used to identify the differentially expressed genes among five treatment groups: baicalin, jasminoidin, ursodeoxycholic acid, sham, and vehicle, and MetaCore analysis software was applied to identify the significantly altered pathways, processes and interaction network parameters. At pathway level, 46, 25, and 31 pathways were activated in the baicalin, jasminoidin, and ursodeoxycholic acid groups, respectively. Thirteen pathways mainly related with apoptosis and development were commonly altered in the three groups. Additionally, baicalin also targeted pathways related with development, neurophysiologic process and cytoskeleton remodeling, while jasminoidin targeted pathways related with cell cycle and ursodeoxycholic acid targeted those related with apoptosis and development. At process level, three processes were commonly regulated by the three groups in the top 10 processes. Further interaction network analysis revealed that baicalin, jasminoidin, and ursodeoxycholic acid displayed unique features either on network topological parameters or network structure. Additional overlapping analysis demonstrated that compared with ursodeoxycholic acid, the pharmacological mechanism of baicalin was more similar with that of jasminoidin in treating brain ischemia. The data presented in this study may contribute toward the understanding of the common and differential pharmacological mechanisms of these three compounds.

RETRACTED: IL-37 reduces inflammatory response after cerebral ischemia and reperfusion injury through down-regulation of pro-inflammatory cytokines

The purpose of the present study was to determine the effects of interleukin-37 (IL-37) on brain inflammation induced by ischemia/reperfusion (I/R). A transgenic mouse strain was generated to express human IL-37 (hIL-37tg), and these mice were subjected to cerebral I/R. We made middle cerebral artery ischemia-reperfusion model in mice. Compared with wild type, scores of cerebral infarct size and neurologic impairment in hIL-37tg mice were obviously lower after 24h ischemia and 72 h reperfusion. Light microscopic and electron microscopic results showed that cerebral ischemia-reperfusion injury in hIL-37tg mice was less serious than that in WT mice. The results showed that IL-37 participates in the process of cerebral ischemia-reperfusion injury probably through decrease of pro-inflammatory cytokines; TNF-alpha, IL-6, IL-1β, MCP-1 and MIP-1. Our study suggests that IL-37 is one of the mechanisms of cerebral ischemia-reperfusion injury besides its important role in innate immunity and IL-37 may become a new target for prevention of cerebral ischemia-reperfusion injury.

Expression of netrin-1 and its receptors, deleted in colorectal cancer and uncoordinated locomotion-5 homolog B, in rat brain following focal cerebral ischemia reperfusion injury.

Netrin-1 is currently one of the most highly studied axon guidance factors. Netrin-1 is widely expressed in the embryonic central nervous system, and together with the deleted in colorectal cancer and uncoordinated locomotion-5 homolog B receptors, netrin-1 plays a guiding role in the construction of neural conduction pathways and the directional migration of neuronal cells. In this study, we established a rat middle cerebral artery ischemia reperfusion model using the intraluminal thread technique. Immunofluorescence microscopy showed that the expression of netrin-1 and deleted in colorectal cancer in the ischemic penumbra was upregulated at 1 day after reperfusion, reached a peak at 14 days, and decreased at 21 days. There was no obvious change in the expression of uncoordinated locomotion-5 homolog B during this time period. Double immunofluorescence labeling revealed that netrin-1 was expressed in neuronal cells and around small vessels, but not in astrocytes and microglia, while deleted in colorectal cancer was localized in the cell membranes and protrusions of neurons and astrocytes. Our experimental findings indicate that netrin-1 may be involved in post-ischemic repair and neuronal protection via deleted in colorectal cancer receptors.

Reduced cerebral ischemia-reperfusion injury in Toll-like receptor 4 deficient mice

Inflammatory reaction plays an important role in cerebral ischemia-reperfusion injury, however, its mechanism is still unclear. Our study aims to explore the function of Toll-like receptor 4 (TLR4) in the process of cerebral ischemia-reperfusion. We made middle cerebral artery ischemia-reperfusion model in mice with line embolism method. Compared with C3H/OuJ mice, scores of cerebral water content, cerebral infarct size and neurologic impairment in C3H/Hej mice were obviously lower after 6 h ischemia and 24 h reperfusion. Light microscopic and electron microscopic results showed that cerebral ischemia-reperfusion injury in C3H/Hej mice was less serious than that in C3H/OuJ mice. TNF-α and IL-6 contents in C3H/HeJ mice were obviously lower than that in C3H/OuJ mice with ELISA. The results showed that TLR4 participates in the process of cerebral ischemia-reperfusion injury probably through decrease of inflammatory cytokines. TLR4 may become a new target for prevention of cerebral ischemia-reperfusion injury. Our study suggests that TLR4 is one of the mechanisms of cerebral ischemia-reperfusion injury besides its important role in innate immunity.

Acidosis Causes Endoplasmic Reticulum Stress and Caspase-12-Mediated Astrocyte Death

Endoplasmic reticulum (ER) stress leads to activation of caspase-12, which in turn can lead to activation of caspase-3 and cell death. Here we report that transient acidosis induces ER stress and caspase-12-mediated cell death in mouse astrocytes. After a 3-hour incubation at pH 6.0, astrocytes exhibited delayed cell death associated with nuclear condensation and fragmentation. Cell death was reduced by the protein synthesis inhibitor cycloheximide, further suggesting an active cell death program. Acidosis increased the expression of the ER chaperone protein GRP-78, indicative of ER stress. Acidosis also increased caspase-12 mRNA expression, caspase-12 protein expression, cleavage of caspase-12 to its active form, and activation of caspase-3. Each of these effects was suppressed in astrocytes pretreated with caspase-12 antisense phosphorodiamidate morpholino oligodeoxynucleotides (PMOs). Caspase-12 antisense PMOs also reduced the cell death induced by acidosis. Immunoprecipitation studies showed dissociation of both caspase-12 and Ire1-alpha from GRP-78, thereby suggesting a mechanism by which acidosis can initiate the ER stress response. To evaluate caspase-12 activation in vivo, rats were subjected to middle cerebral artery ischemia-reperfusion. Immunostaining of brain sections harvested 24 hours later showed increased caspase-12 expression and nuclear condensation in astrocytes of the periinfarct region exposed to acidosis during ischemia. These findings suggest that acidosis induces ER stress and caspase-12 activation, and that these changes may contribute to delayed cell death after ischemia.