An enriched environment promotes synaptic plasticity and cognitive recovery after permanent middle cerebral artery occlusion in mice

Cerebral ischemia activates an endogenous repair program that induces plastic changes in neurons. In this study, we investigated the effects of environmental enrichment on spatial learning and memory as well as on synaptic remodeling in a mouse model of chronic cerebral ischemia, produced by subjecting adult male C57 BL/6 mice to permanent left middle cerebral artery occlusion. Three days postoperatively, mice were randomly assigned to the environmental enrichment and standard housing groups. Mice in the standard housing group were housed and fed a standard diet. Mice in the environmental enrichment group were housed in a cage with various toys and fed a standard diet. Then, 28 days postoperatively, spatial learning and memory were tested using the Morris water maze. The expression levels of growth-associated protein 43, synaptophysin and postsynaptic density protein 95 in the hippocampus were analyzed by western blot assay. The number of synapses was evaluated by electron microscopy. In the water maze test, mice in the environmental enrichment group had a shorter escape latency, traveled markedly longer distances, spent more time in the correct quadrant(northeast zone), and had a higher frequency of crossings compared with the standard housing group. The expression levels of growth-associated protein 43, synaptophysin and postsynaptic density protein 95 were substantially upregulated in the hippocampus in the environmental enrichment group compared with the standard housing group. Furthermore, electron microscopy revealed that environmental enrichment increased the number of synapses in the hippocampal CA1 region. Collectively, these findings suggest that environmental enrichment ameliorates the spatial learning and memory impairment induced by permanent middle cerebral artery occlusion. Environmental enrichment in mice with cerebral ischemia likely promotes cognitive recovery by inducing plastic changes in synapses.

Predictors of short-term outcome in patients with acute middle cerebral artery occlusion: unsuitability of fluid-attenuated inversion recovery vascular hyperintensity scores

Fluid-attenuated inversion recovery （FLAIR） vascular hyperintensity （FVH） is used to assess leptomeningeal collateral circulation, but clinical outcomes of patients with FVH can be very different. The aim of the present study was to assess a FVH score and explore its relationship with clinical outcomes. Patients with acute ischemic stroke due to middle cerebral artery M1 occlusion underwent magnetic resonance imaging and were followed up at 10 days （National Institutes of Health Stroke Scale） and 90 days （modified Rankin Scale） to determine short-term clinical outcomes. Effective collateral circulation indirectly improved recovery of neurological function and short-term clinical outcome by extending the size of the pial penumbra and reducing infarct lesions. FVH score showed no correlation with 90-day functional clinical outcome and was not sufficient as an independent predictor of short-term clinical outcome.

Apparent diffusion coefficient evaluation for secondary changes in the cerebellum of rats after middle cerebral artery occlusion

Supratentorial cerebral infarction can cause functional inhibition of remote regions such as the cerebellum, which may be relevant to diaschisis. This phenomenon is often analyzed using positron emission tomography and single photon emission CT. However, these methods are expensive and radioactive. Thus, the present study quantified the changes of infarction core and remote regions after unilateral middle cerebral artery occlusion using apparent diffusion coefficient values. Diffu- sion-weighted imaging showed that the area of infarction core gradually increased to involve the cerebral cortex with increasing infarction time. Diffusion weighted imaging signals were initially in- creased and then stabilized by 24 hours. With increasing infarction time, the apparent diffusion co- efficient value in the infarction core and remote bilateral cerebellum both gradually decreased, and then slightly increased 3-24 hours after infarction. Apparent diffusion coefficient values at remote regions （cerebellum） varied along with the change of supratentorial infarction core, suggesting that the phenomenon of diaschisis existed at the remote regions. Thus, apparent diffusion coefficient values and diffusion weighted imaging can be used to detect early diaschisis.

Effects of Echinacoside on Histio-central Levels of Active Mass in Middle Cerebral Artery Occlusion Rats

Objective To investigate the effects of echinacoside on the extracellular striatal levels of norepinephrine（NE）,dopamine（DA）,homovanillic acid（HVA）,3,4-dihydroxyphenylethanoid acid（DOPAC）,5-hydroxyindoleacetic acid（HIAA）,and 5-hydroxytryptamine（5-HT） in middle cerebral artery occlusion（MCAO rats.Methods The middle cerebral artery was occluded in male Sprague-Dawley rats.Three days later microdialysis probes were placed into the right striatum of MCAO rat brains and the brains were perfused with Ringer＇s solution at a rate of 1.5 μL/min.Cerebral microdialysates were collected every 30 minutes from awake and freely moving rats before assaying for NE,DA,HVA,DOPAC,HIAA,and 5-HT levels by reverse phase HPLC with electrochemistry.Results Three days after MCAO,the extracellular striatal levels of NE,DA,DOPAC,HIAA,HVA,and 5-HT of the MCAO rats increased significantly（at least P0.05 vs.control）.However,simultaneous treatment with echinacoside（30.0 or 15.0 mg/kg） attenuated these increases（at least P0.05 vs.non-treated model rats）.Conclusion These results imply that echinacoside may protect striatal dopa minergic neurons from the injury induced by MCAO and may help prevent and treat cerebral ischemic diseases.

Middle cerebral artery occlusion methods in rat versus mouse model of transient focal cerebral ischemic stroke

Experimental stroke research commonly employs focal cerebral ischemic rat models （Bederson et al., 1986a; Longa et al., 1989）. In human patients, ischemic stroke typically results from thrombotic or embolic occlusion of a major cerebral artery, usually the mid- dle cerebral artery （MCA）. Experimental focal cerebral ischemia models have been employed to mimic human stroke （Durukan and Tatlisumak, 2007）. Rodent models of focal cerebral ischemia that do not require craniotomy have been developed using intraluminal suture occlusion of the MCA （MCA occlusion, MCAO） （Rosamond et al., 2008）. Furthermore, mouse MCAO models have been wide- ly used and extended to genetic studies of cell death or recovery mechanisms （Liu and McCullough, 2011）. Genetically engineered mouse stroke models are particularly useful for evaluation of isch- emic pathophysiology and the design of new prophylactic, neuro- protective, and therapeutic agents and interventions （Armstead et al., 2010）. During the past two decades, MCAO surgical techniques have been developed that do not reveal surgical techniques for mouse MCAO model engineering. Therefore, we compared MCAO surgical methods in rats and mice.

Investigation multi-target synergistic mechanism of Choerospondias axillaris in the treat of cerebral ischemia based on systems pharmacology and experimental verification

Background:Choerospondias axillaris(CA)is a traditional Mongolian medicine that has been proven to have a good therapeutic effect on cerebrovascular disease.Cerebral Ischemia(CI)is a severe and life-threatening cerebrovascular disease.However,the specific mechanism of action of CA in the treatment of CI is still unclear.Methods:In this study,the related targets and pathways of CA in the treatment of CI were first predicted by system pharmacology and then verified by relevant experiments.Results:The results showed that 12 active ingredients and 208 targets were selected.Further validation through protein-protein interaction(PPI)network analysis and active ingredients-target-pathway(A-T-P)network analysis has confirmed the pivotal roles of the main bioactive constituents,including quercetin,kaempferol,naringin,β-sitosterol,and gallic acid.These components exert their anti-ischemic effects by modulating key targets such as IL6,TNF,MAPK3,and CASP3,thereby regulating the PI3K-Akt,HIF-1,and MAPK signaling pathways,which are integral to processes like inflammation,apoptosis,and oxidative stress.More importantly,through experimental verification,this study confirmed our prediction that CAE significantly reduced neurological function scores,infarct volume,and the percentage of apoptosis neurons.Conclusion:This indicates that CA acts on CI through multi-target synergistic mechanism,and this study provides theoretical basis for the clinical application of CA.

Protective Effect of Tetrandrine and Fructose-1,6-diphos phate on the Model of Focal Cerebral Ischemia in Rats

The effect of tetrandrine (Tet) on the infarction area and volume of rat brain induced by middle cerebral artery occlusion (MCAO) was investigated. The treatment with Tet 7.5, 12.0 or 15.0 mg·kg 1 , or with fructose 1,6 diphosphate (FDP) 200 and 350 mg·kg 1 ip immediately after MCAO, respectively, significantly reduced the infarction area and volume in a dose dependent manner. MK801 and FDP also displayed a protective effect on brain ischemia. A combination of Tet and FDP administered immediately after MCAO, produced a more potent protective effect than those treated with Tet or FDP alone. When Tet or FDP was administered 1 h and 2 h after MCAO, respectively, they could still significantly reduce the infarction area and volume of brain tissue. But, there was no significant protective effect when these two compounds were given 3 h after MCAO.

Puerarin protects brain tissue against cerebral ischemia/reperfusion injury by inhibiting the inflammatory response

Puerarin, a traditional Chinese medicine, exerts a powerful neuroprotective effect in cerebral ischemia/reperfusion injury, but its mechanism is unknown. Here, we established rat models of middle cerebral artery ischemia/reperfusion injury using the suture method. Puerarin （100 mg/kg） was administered intraperitoneally 30 minutes before middle cerebral artery occlusion and 8 hours after reperfusion. Twenty-four hours after reperfusion, we found that puerarin significantly improved neurological deficit, reduced infarct size and brain water content, and notably diminished the expression of Toll-like receptor-4, myeloid differentiation factor 88, nuclear factor kappa B and tumor necrosis factor-α in the ischemic region. These data indicate that puerarin exerts an anti-inflammatory protective effect on brain tissue with ischemia/reperfusion damage by downregulating the expression of multiple inflammatory factors.

Influence of Ren and Du meridian electro-acupuncture on neural stem cell proliferation and extracellular signal-regulated kinase pathway in a rat model of focal cerebral ischemia injury

BACKGROUND： Studies have shown that electro-acupuncture at the Ren meridian could improve proliferation of subventricular zone neural stem cells in cerebral-ischemic rats. However, there are few reports on the influence of electro-acupuncture at the Du meridian on neural stem cell proliferation. OBJECTIVE： To observe the influence of electro-acupuncture at Ren and Du meridians on neural stem cell proliferation in the subventricular zone and altered signal transduction in cerebral ischemia rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Human Anatomy, Medical College of Sun Yat-sen University from May 2006 to February 2008. MATERIALS： Mouse anti-rat bromodeoxyuridine （BrdU） monoclonal antibody was provided by Sigma, USA; mouse anti-rat nestin monoclonal antibody and extracellular signal-regulated protein kinase （ERK） specific inhibitor PD98059 were provided by Calbiochem, Germany; acupuncture needle was provided by Suzhou Acupuncture Supplies, China. METHODS： A total of 126 rats were randomly assigned to four groups： model （n = 36）, Du meridian （n = 36）, Ren/Du meridian （n = 36）, and Ren/Du meridian ＋ PD98059 （n = 18）. Rats in the Ren/Du meridian ＋ PD98059 group were observed on days 7 （n = 6） and 14 （n = 12） after cerebral ischemia injury. Rats in the model, Du meridian, and Ren/Du meridian groups were observed on days 7, 14, and 28 after cerebral ischemia injury, with 12 rats per group at each time point. Thread occlusion was used to establish middle cerebral artery occlusion models. Electro-acupuncture was performed at Renzhong （DU 26） and Baihui （DU 20） acupoints in the Du meridian group, as well as Chengjiang （RN 24）, Guanyuan （RN 4）, Renzhong, and Baihuiacupoints in the Ren/Du meridian and Ren/Du meridian ＋ PD98059 groups 2 days after model establishment. In addition, electro-acupuncture stimulation with disperse-dense waves was performed, with 30 Hz disperse wave, 100 Hz dense wave, and 5 V intensity for 20 minutes. Rats in the Ren/Du meridian ＋ PD98059 group were treated with 0.2 pg PD98059 injection into the subventricular zone, 2 pL per rat. Rats in the model group were not treated with electro-acupuncture. MAIN OUTCOME MEASURES： BrdU/nestin immunofluorescent staining was used to detect proliferating neural stem cells in the subventricular zone of cerebral ischemia rats; Western blot was used to determine phosphorylated ERK1 and 2 （pERK1/2） expression in the subventricular zone. RESULTS： On days 14 and 28 after cerebral ischemia, there were significantly more BrdU-positive and BrdU/nestin-positive cells in the Ren/Du meridian group compared with the Du meridian group （P 〈 0.05）. PD98059 decreased the number of BrdU-positive and BrdU/nestin-positive cells induced by electro-acupuncture at the/：ten and Du meridians （P 〈 0.05）. On days 7, 14, and 28 after treatment, pERK1/2 expression was significantly greater in the Du meridian and Ren/Du meridian groups compared with the model group （P 〈 0.05）. The promoting effect of electro-acupuncture at Ren and Du meridians on ERK1/2 phosphorylation was superior to electro-acupuncture at the Du meridian alone on day 14 after model induction （P 〈 0.05）. However, PD98059 completely abolished the promoting effect of electro-acupuncture at Ren/Du meridians on pERK1/2 expression （P 〈 0.05）. CONCLUSION： Electro-acupuncture at Ren and Du meridians increased proliferation of subventricular zone neural stem cells, which was related to activation of the ERK pathway in a rat model of cerebral ischemia injury.

Comparison of the anti-apoptotic effects of 15-and 35-minute suspended moxibustion after focal cerebral ischemia/reperfusion injury

Heat-sensitive suspended moxibustion has a neuroprotective effect against focal cerebral ischemia/reperfusion injury, but the underly- ing mechanisms remain unclear. The duration of heat-sensitive suspended moxibustion （usually from 30 minutes to 1 hour） is longer than traditional suspended moxibustion （usually 15 minutes）. However, the effects of 15- and 35-minute suspended moxibustion in rats with cerebra/ischemia/reperfusion injury are poorly understood. In this study, we performed 15- or 35-minute suspended moxibustion at acupoint Dazhui （GV14） in an adult rat model of focal cerebral ischemia/reperfusion injury. Infarct volume was evaluated with the 2,3,5-triphenyltetrazolium chloride assay. Histopathological changes and neuronal apoptosis at the injury site were assessed by hematoxy- lin-eosin staining and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Caspase-9 and caspase-3 expression at the in- jury site was detected using immunofluorescent staining. Bax and Bcl-2 expression at the injury site was assessed using western blot assay. In the 35-minute moxibustion group, infarct volume was decreased, neuronal apoptosis was reduced, caspase-9, caspase-3 and Bax expres- sion was lower, and Bcl-2 expression was increased, compared with the 15-minute moxibustion group. Our findings show that 35-minute moxibustion has a greater anti-apoptotic effect than 15-minute moxibustion after focal cerebral ischemia/reperfusion injury.

Do pyroptosis, apoptosis, and necroptosis (PANoptosis) exist in cerebral ischemia? Evidence from cell and rodent studies

Some scholars have recently developed the concept of PANoptosis in the study of infectious diseases where pyroptosis,apoptosis and necroptosis act in consort in a multimeric protein complex,PANoptosome.This allows all the components of PANoptosis to be regulated simultaneously.PANoptosis provides a new way to study the regulation of cell death,in that different types of cell death may be regulated at the same time.To test whether PANoptosis exists in diseases other than infectious diseases,we chose cerebral ischemia/reperfusion injury as the research model,collected articles researching cerebral ischemia/reperfusion from three major databases,obtained the original research data from these articles by bibliometrics,data mining and other methods,then integrated and analyzed these data.We selected papers that investigated at least two of the components of PANoptosis to check its occurrence in ischemia/reperfusion.In the cell model simulating ischemic brain injury,pyroptosis,apoptosis and necroptosis occur together and this phenomenon exists widely in different passage cell lines or primary neurons.Pyroptosis,apoptosis and necroptosis also occurred in rat and mouse models of ischemia/reperfusion injury.This confirms that PANoptosis is observed in ischemic brain injury and indicates that PANoptosis can be a target in the regulation of various central nervous system diseases.

Neuroprotective effect of baicalin on focal cerebral ischemia in rats

Baicalin, a flavonoid compound from the root of the herb Scutellaria baicalensis Georgi, has been widely used to treat patients with inflammatory disease. The aim of this study was to assess the efficacy of baicalin in a rat model of focal cerebral ischemia. Adult male Sprague-Dawley rat models of cerebral artery occlusion were established and then randomly and equally divided into three groups： ischemia（cerebral ischemia and reperfusion）, valproic acid（cerebral ischemia and reperfusion ＋ three intraperitoneal injections of valproic acid; positive control）, and baicalin（cerebral ischemia and reperfusion ＋ intraperitoneal injection of baicalin for 21 days）. Neurological deficits were assessed using the postural reflex test and forelimb placing test at 3, 7, 14, and 21 days after ischemia. Rat cerebral infarct volume was measured using 2,3,5-triphenyltetrazolium chloride（TTC） staining method. Pathological change of ischemic brain tissue was assessed using hematoxylin-eosin staining. In the baicalin group, rat neurological function was obviously improved, cerebral infarct volume was obviously reduced, and the pathological impairment of ischemic brain tissue was obviously alleviated compared to the ischemia group. Cerebral infarct volume was similar in the valproic acid and baicalin groups. These findings suggest that baicalin has a neuroprotective effect on cerebral ischemia.

12 hours after cerebral ischemia is the optimal time for bone marrow mesenchymal stem cell transplantation

Cell therapy using stem cell transplantation against cerebral ischemia has been reported. However, it remains controversial regarding the optimal time for cell transplantation and the transplantation route. Rat models of cerebral ischemia were established by occlusion of the middle cerebral artery. At 1, 12 hours, 1, 3, 5 and 7 days after cerebral ischemia, bone marrow mesenchymal stem cells were injected via the tail vein. At 28 days after cerebral ischemia, rat neurological function was evaluated using a 6-point grading scale and the pathological change of ischemic cerebral tissue was observed by hematoxylin-eosin staining. Under the fluorescence microscope, the migration of bone marrow mesenchymal stem cells was examined by PKH labeling. Caspase-3 activity was measured using spectrophotometry. The optimal neurological function recovery, lowest degree of ischemic cerebral damage, greatest number of bone marrow mesenchymal stem cells migrating to peri-ischemic area, and lowest caspase-3 activity in the ischemic cerebral tissue were observed in rats that underwent bone marrow mesenchymal stem cell transplantation at 12 hours after cerebral ischemia. These findings suggest that 12 hours after cerebral ischemia is the optimal time for tail vein injection of bone marrow mesenchymal stem cell transplantation against cerebral ischemia, and the strongest neuroprotective effect of this cell therapy appears at this time.

Characterization of astrocytes and microglial cells in the hippocampal CA1 region after transient focal cerebral ischemia in rats treated with Ilexonin A

Ilexonin A is a compound isolated from the root of Ilex pubescens,a traditional Chinese medicine.Ilexonin A has been shown to play a neuroprotective role by regulating the activation of astrocytes and microglia in the peri-infarct area after ischemia.However,the effects of ilexonin A on astrocytes and microglia in the infarct-free region of the hippocampal CA1 region remain unclear.Focal cerebral ischemia models were established by 2-hour occlusion of the middle cerebral artery in rats.Ilexonin A(20,40 or 80 mg/kg)was administered immediately after ischemia/reperfusion.The astrocyte marker glial fibrillary acidic protein,microglia marker Iba-1,neural stem cell marker nestin and inflammation markers were detected by immunohistochemistry and western blot assay.Expression levels of tumor necrosis factor-αand interleukin 1βwere determined by enzyme linked immunosorbent assay in the hippocampal CA1 tissue.Astrocytes were activated immediately in progressively increasing numbers from 1,3,to 7 days post-ischemia/reperfusion.The number of activated astrocytes further increased in the hippocampal CA1 region after treatment with ilexonin A.Microglial cells remained quiescent after ischemia/reperfusion,but became activated after treatment with ilexonin A.Ilexonin A enhanced nestin expression and reduced the expression of tumor necrosis factor-αand interleukin 1βin the hippocampus post-ischemia/reperfusion.The results of the present study suggest that ilexonin A has a neuroprotective effect in the hippocampus after ischemia/reperfusion,probably through regulating astrocytes and microglia activation,promoting neuronal stem cell proliferation and reducing the levels of pro-inflammatory factors.This study was approved by the Animal Ethics Committee of the Fujian Medical University Union Hospital,China.

Hydrogen sulfide intervention in focal cerebral ischemia/reperfusion injury in rats

The present study aimed to explore the mechanism underlying the protective effects of hydrogen sulfide against neuronal damage caused by cerebral ischemia/reperfusion. We established the middle cerebral artery occlusion model in rats via the suture method. Ten minutes after middle cerebral artery occlusion, the animals were intraperitoneally injected with hydrogen sulfide donor compound sodium hydrosulfide. Immunofluorescence revealed that the immunoreactivity of P2X7 in the cerebral cortex and hippocampal CA1 region in rats with cerebral ischemia/reperfusion injury decreased with hydrogen sulfide treatment. Furthermore, treatment of these rats with hydrogen sulfide significantly lowered mortality, the Longa neurological deficit scores, and infarct volume. These results indicate that hydrogen sulfide may be protective in rats with local cerebral ischemia/reperfusion injury by down-regulating the expression of P2X7 receptors.

Experimental Study on the Protection of Agrimony Extracts from Different Extracting Methods against Cerebral Ischemia-Reperfusion Injury

Objective To study the protective effect of agrimony extracts from different extracting methods on cerebral ischemia-reperfusion injury in rats, in order to optimize the extraction scheme of agrimony.Methods Male rats were randomly assigned into seven groups: 1. Sham-operated group, 2. Untreated MCAO group (MCAO), 3. Petroleum ether extract of Agrimonia pilosa treated MCAO group (PEA), 4. Ethyl acetate extract of Agrimonia pilosa treated MCAO group (EAEA), 5. Ethanol extract of Agrimonia pilosa treated MCAO group (EEA), 6. Water extract of Agrimonia pilosa treated MCAO group (WEA), 7. Nimodipine treated MCAO group (NP). Intragastrical drug administration (i.g) was performed at 0 and 6 hours after MCAO.Neurological function tests were performed after reperfusion for 24 hours, then the brain was removed for the evaluations of the cerebral infarction volume (percentage of total brain volume) by immunohistochemistry,histological changes (hematoxylin-eosin staining), Na+/K+-ATPase, Ca2+-ATPase (modified method of Svoboda and Mosinger), mRNA expression of Tumor suppressor gene (P53) and hot shock protein (HSP70)(quantitative real-time PCR).Results The neurological function of MCAO group had significantly higher scores than the sham group (P<0.01). The WEA group showed a significantly lower neurological score than the MCAO group (P<0.05),indicating the protective effect of WEA on neurological deficits. The mean infarction volumes of WEA (13.5±6.6%, F=4.75, P<0.01), EEA (19.90±6.90%, F=5.23, P<0.01), PEA (20.40±5.30%, F=4.68,P<0.01) and EAEA (22.50±10.50%, F=6.25, P<0.05) group were all significantly smaller than that of MCAO group (29.40±6.50%). HE staining demonstrated that, compared to the treated groups, the infarcted cerebral tissue of MCAO group had more swelling neural cells, lighter stained nucleus, fewer and irregularly distributed neurons. The activity of Na+/K+-ATPase and Ca2+-ATPase reduced in the MCAO group (3.67±0.48 U/mg,1.28±0.26 U/mg, respectively), and were significantly higher in WEA group (7.56±0.85 U/mg, F=12.65,P=0.010; 3.59±0.22 U/mg, F=8.32, P=0.041, respectively). The MCAO group showed significantly elevated P53 and HSP70 mRNA expressions compared to the sham group (P<0.01, P<0.05). P53 mRNA expressions in Agrimony extracts treated groups were significantly lower than that of the MCAO group (all P<0.01), with the WEA group showing the greatest difference from MCAO group. The HSP70 mRNA level of the treated groups were not significantly different from that of the MCAO group.Conclusions Treatment using water extracts of agrimony can promote the best functional and metabolic recovery for rat model of cerebral ischemia-reperfusion injury, which maybe relate with the upregulation of energy metabolism in nerve cells after MCAO.

Vav1 promotes inflammation and neuronal apoptosis in cerebral ischemia/reperfusion injury by upregulating microglial and NLRP3 inflammasome activation

Microglia,which are the resident macrophages of the central nervous system,are an important part of the inflammatory response that occurs after cerebral ischemia.Vav guanine nucleotide exchange factor 1(Vav1) is a guanine nucleotide exchange factor that is related to microglial activation.However,how Vav1 participates in the inflammato ry response after cerebral ischemia/reperfusion inj ury remains unclea r.In this study,we subjected rats to occlusion and repe rfusion of the middle cerebral artery and subjected the BV-2 mic roglia cell line to oxygen-glucose deprivatio n/reoxygenation to mimic cerebral ischemia/repe rfusion in vivo and in vitro,respectively.We found that Vav1 levels were increased in the brain tissue of rats subjected to occlusion and reperfusion of the middle cerebral arte ry and in BV-2 cells subjected to oxygen-glucose deprivation/reoxygenation.Silencing Vav1 reduced the cerebral infarct volume and brain water content,inhibited neuronal loss and apoptosis in the ischemic penumbra,and im p roved neurological function in rats subjected to occlusion and repe rfusion of the middle cerebral artery.Further analysis showed that Vav1 was almost exclusively localized to microglia and that Vav1 downregulation inhibited microglial activation and the NOD-like receptor pyrin 3(NLRP3) inflammasome in the ischemic penumbra,as well as the expression of inflammato ry facto rs.In addition,Vov1 knoc kdown decreased the inflammatory response exhibited by BV-2 cells after oxygen-glucose deprivation/reoxyge nation.Taken together,these findings show that silencing Vav1 attenuates inflammation and neuronal apoptosis in rats subjected to cerebral ischemia/repe rfusion through inhibiting the activation of mic roglia and NLRP3 inflammasome.

Nonhuman primate models of focal cerebral ischemia

Rodents have been widely used in the production of cerebral ischemia models. However, successful therapies have been proven on experimental rodent stroke model, and they have often failed to be effective when tested clinically. Therefore, nonhuman primates were recommended as the ideal alternatives, owing to their similarities with the human cerebrovascular system, brain metabolism, grey to white matter ratio and even their rich behavioral repertoire. The present review is a thorough summary of ten methods that establish nonhuman primate models of focal cerebral ischemia; electrocoagulation, endothelin-1-induced occlusion, microvascular clip occlusion, autologous blood clot embolization, balloon inflation, microcatheter embolization, coil embolization, surgical suture embolization, suture, and photochemical induction methods. This review addresses the advantages and disadvantages of each method, as well as precautions for each model, compared nonhuman primates with rodents, different species of nonhuman primates and different modeling methods. Finally it discusses various factors that need to be considered when modelling and the method of evaluation after modelling. These are critical for understanding their respective strengths and weaknesses and underlie the selection of the optimum model.

Ki20227 aggravates apoptosis,inflammatory response,and oxidative stress after focal cerebral ischemia injury

The survival of microglia depends on the colony-stimulating factor-1 receptor(CSF1R)signaling pathway under physiological conditions.Ki20227 is a highly selective CSF1R inhibitor that has been shown to change the morphology of microglia.However,the effects of Ki20227 on the progression of ischemic stroke are unclear.In this study,male C57 BL/6 mouse models of focal cerebral ischemic injury were established through the occlusion of the middle cerebral artery and then administered 3 mg/g Ki20227 for 3 successive days.The results revealed that the number of ionized calcium-binding adaptor molecule 1/bromodeoxyuridine double positive cells in the infarct tissue was reduced,the degree of edema was increased,neurological deficits were aggravated,infarct volume was increased,and the number of peri-infarct Nissl bodies was reduced.The number of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells in the peri-infarct tissue was increased.The expression levels of Bax and Cleaved caspase-3 were up-regulated.Bcl-2 expression was downregulated.The expression levels of inflammatory factors and oxidative stress-associated factors were increased.These findings suggested that Ki20227 blocked microglial proliferation and aggravated the pathological progression of ischemia/reperfusion injury in a transient middle cerebral artery occlusion model.This study was approved by the Animal Ethics Committee of Lanzhou University Second Hospital(approval No.D2020-68)on March 6,2020.

DNA hypomethylation promotes learning and memory recovery in a rat model of cerebral ischemia/reperfusion injury

Cerebral ischemia/reperfusion injury impairs learning and memory in patients.Studies have shown that synaptic function is involved in the formation and development of memory,and that DNA methylation plays a key role in the regulation of learning and memory.To investigate the role of DNA hypomethylation in cerebral ischemia/reperfusion injury,in this study,we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery and then treated the rats with intraperitoneal 5-aza-2′-deoxycytidine,an inhibitor of DNA methylation.Our results showed that 5-aza-2′-deoxycytidine markedly improved the neurological function,and cognitive,social and spatial memory abilities,and dose-dependently increased the synaptic density and the expression of SYP and SHANK2 proteins in the hippocampus in a dose-dependent manner in rats with cerebral ischemia/reperfusion injury.The effects of 5-aza-2′-deoxycytidine were closely related to its reduction of genomic DNA methylation and DNA methylation at specific sites of the Syp and Shank2 genes in rats with cerebral ischemia/reperfusion injury.These findings suggest that inhibition of DNA methylation by 5-aza-2′-deoxycytidine promotes the recovery of learning and memory impairment in a rat model of cerebral ischemia/reperfusion injury.These results provide theoretical evidence for stroke treatment using epigenetic methods.