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.

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.

A molecular probe carrying anti-tropomyosin 4 for early diagnosis of cerebral ischemia/reperfusion injury

In vivo imaging of cerebral ischemia/reperfusion injury remains an important challenge.We injected porous Ag/Au@SiO_(2) bimetallic hollow nanoshells carrying anti-tropomyosin 4 as a molecular probe into mice with cerebral ischemia/reperfusion injury and observed microvascular changes in the brain using photoacoustic imaging with ultrasonography.At each measured time point,the total photoacoustic signal was significantly higher on the affected side than on the healthy side.Twelve hours after reperfusion,cerebral perfusion on the affected side increased,cerebrovascular injury worsened,and anti-tropomyosin 4 expression increased.Twenty-four hours after reperfusion and later,perfusion on the affected side declined slowly and stabilized after 1 week;brain injury was also alleviated.Histopathological and immunohistochemical examinations confirmed the brain injury tissue changes.The nanoshell molecular probe carrying anti-tropomyosin 4 has potential for use in early diagnosis of cerebral ischemia/reperfusion injury and evaluating its progression.

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.

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.

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.

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.

Neuroprotective effect of penehyclidine hydrochloride on focal cerebral ischemia-reperfusion injury

Penehyclidine hydrochloride can promote microcirculation and reduce vascular permeability. However, the role of penehyclidine hydrochlodde in cerebral ischemia-reperfusion injury remains unclear. In this study, in vivo middle cerebral artery occlusion models were established in experimental rats, and penehyclidine hydrochloride pretreatment was given via intravenous injection prior to model establishment. Tetrazolium chloride, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and immunohistochemical staining showed that, penehyclidine hydrochloride pretreatment markedly attenuated neuronal histopathological changes in the cortex, hippocampus and striatum, reduced infarction size, increased the expression level of BcI-2, decreased the expression level of caspase-3, and inhibited neuronal apoptosis in rats with cerebral ischemia-reperfusion injury. Xanthine oxidase and thiobarbituric acid chromogenic results showed that penehyclidine hydrochloride upregulated the activity of superoxide dismutase and downregulated the concentration of malondialdehyde in the ischemic cerebral cortex and hippocampus, as well as reduced the concentration of extracellular excitatory amino acids in rats with cerebral ischemia-reperfusion injury. In addition, penehyclidine hydrochloride inhibited the expression level of the NR1 subunit in hippocampal nerve cells in vitro following oxygen-glucose deprivation, as detected by PCR. Experimental findings indicate that penehyclidine hydrochloride attenuates neuronal apoptosis and oxidative stress injury after focal cerebral ischemia-reperfusion, thus exerting a neuroprotective effect.

Relationship of gelatinases-tight junction proteins and blood-brain barrier permeability in the early stage of cerebral ischemia and reperfusion

Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This study established a rat model of 1.5-hour middle cerebral artery occlusion with reperfusion. Protein expression levels of claudin-5 and occludin gradually decreased in the early stage of reperfusion, which corresponded to the increase of the gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. In addition, rats that received treatment with matrix metalloproteinase inhibitor N-[（2R）-2-（hydroxamidocarbonylmethyl）-4-methylpenthanoyl]-L- tryptophan methylamide （GM6001） showed a significant reduction in Evans blue leakage and an inhibition of claudin-5 and occludin protein degradation in striatal tissue. These data indicate that matrix metalloproteinase-2 and matrix metalloproteinase-9-mediated claudin-5 and occludin degradation is an important reason for blood-brain barrier leakage in the early stage of reperfusion. The leakage of the blood-brain barrier was present due to gelatinases-mediated degradation of claudin-5 and occludin proteins. We hypothesized that the timely closure of the structural component of the blood-brain barrier （tight junction proteins） is of importance.

Effects of reduction of Sheng-Nao-Kang decoction in focal cerebral ischemia/reperfusion model rats

Aim Reduction of Sheng-Nao-Kang decoction （RSNK）, is a modified traditional Chinese medicinal formula of Sheng-Nao-Kang pill preparation, which is protective in rats against focal cerebral ischemia/reperfusion （I/R） injury. In the current study, we investigate the protective effect of RSNK against apoptosis and oxidative damage induced by cerebral I/R and explore the underlying mechanisms. Cerebral I/R injury was induced by in- traluminal middle cerebral artery occlusion （MCAO） for 2 h followed by reperfusion for 24 h in adult male Sprague- Dawley rats. Rats were randomized into seven groups （n- 8）： Sham group, I/R group, RSNK-treated groups （ 0.7 g · kg ^- 1, 1 . 4 g · kg ^- 1 and 2. 8 g · kg^ - 1 ） , nimodipine （NMP） -treated group and Whitmania pigra Whitman （WW）-treated group. Neurological deficit scores, cerebral humidity content and cerebral infarction volume were measured after the 24 h reperfusion. Malondialdehyde （ MDA）, superoxide dismutase （ SOD）, catalase （ CAT）, inducible nitric oxide synthase （iNOS） and total nitric oxide synthase （TNOS） in serum were measured by assay kits for biochemical analysis. Histological structures of the cortex of the ipsilateral ischemic cerebral hemisphere in rats were observed by Nissl staining. The caspase-3 protein content in the hippocampus and cortex was detected by immunohistochemistry. Additionally, Bax and Bcl-2 protein expressions in the injured brain were evaluated by Western blot. RSNK administration not only markedly improved neurological deficit scores, but also reduced cere- bral humidity content and cerebral infarction volume, lowered MDA content, up-regulated SOD and CAT levels, down-regulated iNOS and TNOS levels, restrained the expression of caspase-3 positive protein and alleviated the Bax and Bcl-2 protein expressions.

Exacerbated VEGF up-regulation accompanies diabetes-aggravated hemorrhage in mice after experimental cerebral ischemia and delayed reperfusion

Reperfusion therapy is the preferred treatment for ischemic stroke,but is hindered by its short treatment window,especially in patients with diabetes whose reperfusion after prolonged ischemia is often accompanied by exacerbated hemorrhage.The mechanisms underlying exacerbated hemorrhage are not fully understood.This study aimed to identify this mechanism by inducing prolonged 2-hour transient intraluminal middle cerebral artery occlusion in diabetic Ins2Akita/+mice to mimic patients with diabetes undergoing delayed mechanical thrombectomy.The results showed that at as early as 2 hours after reperfusion,Ins2Akita/+mice exhibited rapid development of neurological deficits,increased infarct and hemorrhagic transformation,together with exacerbated down-regulation of tight-junction protein ZO-1 and upregulation of blood-brain barrier-disrupting matrix metallopeptidase 2 and matrix metallopeptidase 9 when compared with normoglycemic Ins2+/+mice.This indicated that diabetes led to the rapid compromise of vessel integrity immediately after reperfusion,and consequently earlier death and further aggravation of hemorrhagic transformation 22 hours after reperfusion.This observation was associated with earlier and stronger up-regulation of pro-angiogenic vascular endothelial growth factor(VEGF)and its downstream phospho-Erk1/2 at 2 hours after reperfusion,which was suggestive of premature angiogenesis induced by early VEGF up-regulation,resulting in rapid vessel disintegration in diabetic stroke.Endoplasmic reticulum stress-related pro-apoptotic C/EBP homologous protein was overexpressed in challenged Ins2Akita/+mice,which suggests that the exacerbated VEGF up-regulation may be caused by overwhelming endoplasmic reticulum stress under diabetic conditions.In conclusion,the results mimicked complications in patients with diabetes undergoing delayed mechanical thrombectomy,and diabetes-induced accelerated VEGF up-regulation is likely to underlie exacerbated hemorrhagic transformation.Thus,suppression of the VEGF pathway could be a potential approach to allow reperfusion therapy in patients with diabetic stroke beyond the current treatment window.Experiments were approved by the Committee on the Use of Live Animals in Teaching and Research of the University of Hong Kong[CULATR 3834-15(approval date January 5,2016);3977-16(approval date April 13,2016);and 4666-18(approval date March 29,2018)].

Anti-inflammatory Effect of Heat-sensitive Moxibustion via the NF-κB Signaling Pathway on Cerebral Ischemia/Reperfusion Injury in Rats

Ischemic stroke is universally acknowledged as a common cause of long-term disability or even death. Suspended moxibustion, an indirect form of moxibustion, is when moxibustion is placed superficially over the skin without being in contact with it. Some researchers have used this method to treat stroke patients, but strong evidence of its therapeutic effectiveness is lacking. However, the effect of traditional suspended moxibustion has recently been improved with the development of heat-sensitive suspended moxibustion. Our previous studies showed that moxibustion for 35 min provided a more effective treatment strategy than moxibustion for 15 min, and moxibustion by 35 min with tail temperature increase had a better outcome than that without, however, the mechanism underlying the effect is not clear. In this study, we treated the stroke rats with moxibustion by 35min and divided them into non-heat sensitive moxibustion(NHSM) group and heat sensitive moxibustion (HSM) group according to difference in the tail temperature increase, then we compared the effect and investigated the mechanisms between NHSM and HSM. We found that HSM significantly decreased tail-flick latency, increased neurological function score, decreased infarct volume, reduced inflammatory cells, decreased the expression of inflammatory factor ICAM-1 and reduced the expression of NF-κB p65 and p-IKKα/β in rats with focal cerebral ischemia/reperfusion injury. Our experimental findings revealed that HSM exerted its anti-inflammatory and neuroprotective effects from MCAO-induced injury by decreasing the expression of the NF-κB signaling pathway.

GM1 stabilizes expression of NMDA receptor subunit 1 in the ischemic hemisphere of MCAo/reperfusion rat

Objective: To determine the protective effect of monosialoganglionside (GM1) and evaluate the influence of GM1 on expression of N-methyl-D-aspartate receptor subunit 1 (NMDAR1) in Sprague-Dawley (SD) rats with focal cerebral ische- mia-reperfusion (I/R). Methods: Left middle cerebral artery (MCA) was occluded by an intraluminal suture for 1 h and the brain was reperfused for 72 h in SD rats when infarct volume was measured, GM1 (10 mg/kg) was given ip (intraperitoneally) at 5 min (group A), 1 h (group B) and 2 h (group C) after MCA occlusion (MCAo). Expression of NMDAR1 was detected by Western blot at various time after reperfusion (4 h, 6 h, 24 h, 48 h and 72 h) in ischemic hemispheres of the rats with or without GM1 admin- istered. Results: (1) Adjusted relative infarct volumes of groups A and B were significantly smaller than that of group C and the control group (P<0.01 and P<0.05, respectively). (2) Expression level of NMDAR1 was temporally high at 6 h after reperfusion, and dipped below the normal level at 72 h after reperfusion. GM1 at 5 min after MCAo significantly suppressed the expression of NMDAR1 at 6 h after reperfusion (P<0.05 vs the control). At 72 h after reperfusion, the NMDAR1 expression level of rats treated with GM1 administered (at 5 min or 2 h after MCAo) was significantly higher than that of the control (P<0.05). Conclusion: GM1 can time-dependently reduce infarct volume in rats with focal cerebral I/R partly through stabilizing the expression of NMDAR1.

内源性FGF21通过FGFR1/PI3K/Akt通路减轻MCAO大鼠延迟血管再通后半暗带的血脑屏障损伤

目的:在“时间窗”内恢复闭塞大动脉的血流是急性缺血性卒中的主要治疗策略。既往研究表明“时间窗”后的血管再通治疗可导致严重的缺血/再灌注损伤。然而,大量临床证据提示“时间窗”后的血管再通治疗仍可改善急性缺血性卒中的神经功能转归。本研究探讨大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)后血管再通治疗对缺血半暗带血脑屏障(blood-brain barrier,BBB)的影响及分子机制。方法:MCAO后第3天行血管再通治疗术,通过蛋白质印迹法、伊文思蓝染色和免疫荧光染色检测BBB损伤。MCAO后第7天评估梗死体积和神经功能转归。采用免疫荧光染色和/或蛋白质印迹法观察缺血半暗带中成纤维细胞生长因子21(fibroblast growth factor 21,FGF21)、成纤维细胞生长因子受体1(fibroblast growth factor receptor 1,FGFR1)、磷脂酰肌醇3激酶(phosphatidylinositol-3-kinase,PI3K)和丝氨酸/苏氨酸激酶(serine/threonine kinase,Akt)的表达及其对BBB的影响。结果:MCAO后缺血半暗带伊文思蓝、IgG和白蛋白的外渗增加,但在血管再通后显著下降;Claudin-5、Occludin和紧密连接蛋白ZO-1表达降低,但在血管再通后表达升高,与FGF21、p-FGFR1、PI3K和p-Akt蛋白升高一致。MCAO后第7天,梗死体积缩小,神经功能改善。侧脑室注射FGFR1抑制剂SU5402可下调缺血半暗带区PI3K、p-Akt、Occludin、Claudin-5和ZO-1的表达,减弱血管再通治疗对MCAO大鼠神经功能转归的有利作用。结论:MCAO后第3天的血管再通治疗增加缺血半暗带内源性FGF21的表达,并可通过激活FGFR1/PI3K/Akt通路减轻缺血半暗带BBB损伤,改善MCAO大鼠的神经功能。

Puerarin protects rat brain against ischemia/reperfusion injury by suppressing autophagy via the AMPK-mT OR-ULK1 signaling pathway

Puerarin suppresses autophagy to alleviate cerebral ischemia/reperfusion injury, and accumulating evidence indicates that the AMPKm TOR signaling pathway regulates the activation of the autophagy pathway through the coordinated phosphorylation of ULK1. In this study, we investigated the mechanisms underlying the neuroprotective effect of puerarin and its role in modulating autophagy via the AMPK-m TOR-ULK1 signaling pathway in the rat middle cerebral artery occlusion model of cerebral ischemia/reperfusion injury. Rats were intraperitoneally injected with puerarin, 50 or 100 mg/kg, daily for 7 days. Then, 30 minutes after the final administration, rats were subjected to transient middle cerebral artery occlusion for 90 minutes. Then, after 24 hours of reperfusion, the Longa score and infarct volume were evaluated in each group. Autophagosome formation was observed by transmission electron microscopy. LC3, Beclin-1 p62, AMPK, m TOR and ULK1 protein expression levels were examined by immunofluorescence and western blot assay. Puerarin substantially reduced the Longa score and infarct volume, and it lessened autophagosome formation in the hippocampal CA1 area following cerebral ischemia/reperfusion injury in a dose-dependent manner. Pretreatment with puerarin（50 or 100 mg/kg） reduced Beclin-1 expression and the LC3-II/LC3-I ratio, as well as p-AMPK and p S317-ULK1 levels. In comparison, it increased p62 expression. Furthermore, puerarin at 100 mg/kg dramatically increased the levels of p-m TOR and p S757-ULK1 in the hippocampus on the ischemic side. Our findings suggest that puerarin alleviates autophagy by activating the APMK-m TOR-ULK1 signaling pathway. Thus, puerarin might have therapeutic potential for treating 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.

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.

过表达miR-124-1基因的骨髓间充质干细胞外泌体调控小胶质细胞M2型极化对脑卒中的影响

目的探讨骨髓间充质干细胞(bone marrow derived mesenchymal stem cells,BMMSCs)外泌体(exosomes,Exo)过表达miR-124-1基因(Exo/124-1)调控小胶质细胞(microglia,MG)的M2型极化对脑卒中的影响。方法分离培养大鼠BMMSCs,收集其Exo(BMMSCs-Exo),采用流式细胞术、Western blot与透射电子显微镜(transmission electron microscope,TEM)分别对其进行检测鉴定。30只大鼠简单随机分为假手术组(Sham组)、模型组(MCAO/R组)、Exo移植组(Exo组)、空病毒(Empty lentivirus,Elv)转染Exo移植组(Exo-Elv组)及Exo/124-1移植组(Exo/124-1组),每组6只。Sham组仅行假手术,其余各组均复制大脑中动脉栓塞/再灌注(middle cerebral artery occlusion and reperfusion,MCAO/R)模型。模型复制1 d与14 d后,各移植组动物于右侧脑室植入相应移植物,Sham组、模型组注入相同剂量生理盐水作对照。术后2 h及1、3、7、14、21、28 d,分别对各组动物行改良神经系统严重程度评分(modified neurological severity scores,mNSS)。三苯基四氮唑(triphenyl tetrazolium chloride,TTC)染色检测其梗死体积。在基因与蛋白水平分别检测各组28 d脑组织MG的M1型分子[肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)]、M2型分子(CD206)的表达情况。结果成功获取并鉴定了BMMSCs及其Exo。Exo/124-1显著表达miR-124-1。所有动物(假手术组除外)术后出现神经功能缺损。术后7~28 d,Exo/124-1组的mNSS明显低于MCAO/R组(P<0.05)与Exo组、Exo-Elv组(P<0.01);术后28 d,Exo/124-1组的脑梗死体积、TNF-α的表达明显小于MCAO/R组(P<0.01)与Exo组、Exo-Elv组(P<0.01),CD206的表达显著高于MCAO/R组(P<0.01)与Exo组、Exo-Elv组(P<0.01)。结论BMMSCs-Exo携带miR-124-1基因可能调控MG的M2型极化,抑制M1型介导的炎症反应,促进脑卒中大鼠神经功能的恢复。