Total flavonoid of Litsea coreana leve exerts anti-oxidative effects and alleviates focal cerebral ischemia/reperfusion injury

In this study, we hypothesized that total flavonoid of Litsea coreana leve （TFLC） protects against focal cerebral ischemia/reperfusion injury. TFLC （25, 50, 100 mg/kg） was administered orally to a rat model of focal ischemia/reperfusion injury, while the free radical scavenging agent, edaravone, was used as a positive control drug. Results of neurological deficit scoring, 2,3,5-triphenyl tetrazolium chloride staining, hematoxylin-eosin staining and biochemical tests showed that TFLC at different doses significantly alleviated cerebral ischemia-induced neurological deficits and histopathological changes, and reduced infarct volume. Moreover, it suppressed the increase in the levels of nitrates plus nitrites, malondialdehyde and lactate dehydrogenase, and it diminished the reduction in glu- tathione, superoxide dismutase and catalase activities induced by cerebral ischemia/reperfusion injury. Compared with edaravone, the protective effects of TFLC at low and medium doses （25, 50 mg/kg） against cerebral ischemia/reperfusion injury were weaker, while the protective effects at high dose （100 mg/kg） were similar. Our experimental findings suggest that TFLC exerts neuroprotective effects against focal cerebral ischemia/reperfusion injury in rats, and that the effects may be asso- ciated with its antioxidant activities.     

Neuroprotective effect of pretreatment with ganoderma lucidum in cerebral ischemia/reperfusion injury in rat hippocampus

Ganoderma lucidum is a traditional Chinese medicine,which has been shown to have both anti-oxidative and anti-inflammatory effects,and noticeably decreases both the infarct area and neuronal apoptosis of the ischemic cortex.This study aimed to investigate the protective effects and mechanisms of pretreatment with ganoderma lucidum(by intragastric administration)in cerebral ischemia/reperfusion injury in rats.Our results showed that pretreatment with ganoder-ma lucidum for 3 and 7 days reduced neuronal loss in the hippocampus,diminished the content of malondialdehyde in the hippocampus and serum,decreased the levels of tumor necrosis fac-tor-αand interleukin-8 in the hippocampus,and increased the activity of superoxide dismutase in the hippocampus and serum.These results suggest that pretreatment with ganoderma lucidum was protective against cerebral ischemia/reperfusion injury through its anti-oxidative and an-ti-inflammatory actions.     

An optimal dose of tea polyphenols protects against global cerebral ischemia/reperfusion injury

Previous studies addressing the protection of tea polyphenols against cerebral ischemia/ reperfusion injury often use focal cerebral ischemia models, and the optimal dose is not unified. In this experiment, a cerebral ischemia/reperfusion injury rat model was established using a modified four-vessel occlusion method. Rats were treated with different doses of tea polyphenols (25, 50, 100, 150, 200 mg/kg) via intraperitoneal injection. Results showed that after 2, 6, 12, 24, 48 and 72 hours of reperfusion, peroxide dismutase activity and total antioxidant capacity in brain tissue gradually increased, while malondialdehyde content gradually decreased after tea polyphenol intervention. Tea polyphenols at 200 mg/kg resulted in the most apparent changes. Terminal deoxynucleotidyl transferase-mediated nick end labeling and flow cytometry showed that 200 mg/kg tea polyphenols significantly reduced the number and percentage of apoptotic cells in the hippocampal CA1 region of rats after cerebral ischemia/reperfusion injury. The open field test and elevated plus maze experiments showed that tea polyphenols at 200 mg/kg strengthened exploratory behavior and reduced anxiety of cerebral ischemia/reperfusion injured rats. Experimental findings indicate that tea polyphenols protected rats against cerebral ischemia/ reperfusion injury and 200 mg/kg is regarded as the optimal dose.     

麻黄碱干预脑缺血再灌注损伤的不良反应：不同剂量比较

Ephedrine has protective effect to rats suffered from cerebral ischemia, the aim of the present study was to evaluate the side effects of ephedrine on heart, liver, kidney and cerebrum of rats after ischemic-reperfusion. Sprague-Dawley (SD) rats, suffered from ischemic-reperfusion were randomly divided into 4 groups: A group for ephedrine, B group for ephedrine, C group for ephedrine, and control group （D group）.At each week, hematoxylin eosin staining was used to observe the tissue of all the organs, then, the blood pressure, aspartate aminotransferase (AST), alkaline phosphatase (AKP) and creatinine were tested, also immunohistochemical method was used to test the expression of brain-derived neurotrophic factor (BDNF) on hippocampal CA3 area. The blood pressure values were lower in ephedrine groups than those in control group all the time (P<0.05). The biochemistry results showed that AST、AKP and serum creatinine in ephedrine groups were higher than those in control groups (P<0.05). The expression levels of BDNF on hippocampal CA3 area in ephedrine groups were higher than that in control group at the last three weeks (P<0.05). The pathological section showed that in all the ephedrine groups, we can see congestion, degeneration and edema of tissues. These findings indicate that ephedrine may have side effects on heart, liver, kidney and cerebrum in ischemic/reperfusion rats. There may be correlation between the side effects and dose, the side effects are enhanced with an increased dose of ephedrine. The injury of the above organs also may be transient, which can be recovered after discontinuation of treatment.     

Anti-inlfammatory properties of lipoxin A4 protect against diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury

Lipoxin A4 can alleviate cerebral ischemia/reperfusion injury by reducing the inlfammatory reaction, but it is currently unclear whether it has a protective effect on diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury. In this study, we established rat models of diabetes mellitus using an intraperitoneal injection of streptozotocin. We then induced focal cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery for 2 hours and reperfusion for 24 hours. After administration of lipoxin A4via the lateral ventricle, infarction volume was reduced, the expression levels of pro-inlfammatory factors tumor necrosis factor alpha and nuclear fac-tor-kappa B in the cerebral cortex were decreased, and neurological functioning was improved. These ifndings suggest that lipoxin A4 has strong neuroprotective effects in diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury and that the underlying mech-anism is related to the anti-inlfammatory action of lipoxin A4.     

13-Methyltetradecanoic acid mitigates cerebral ischemia/reperfusion injury

13-Methyltetradecanoic acid can stabilize cell membrane and have anti-inlfammatory, antioxidant and anti-apoptotic effects. Previous studies mainly focused on peripheral nerve injury, but seldom on the central nervous system. We investigated whether these properties of 13-methyltetradecanoic acid have a neuroprotective effect on focal cerebral ischemia/reperfusion injury, and detected the expression of basic ifbroblast growth factor and vascular endothelial growth factor. This study established rat models of middle cerebral artery occlusion/reperfusion injury by ischemia for 2 hours and reperfusion for 24 hours. At the beginning of reperfusion, 13-methyltetradecanoic acid 10, 40 or 80 mg/kg was injected into the tail vein. Results found that various doses of 13-methyltetradecanoic acid effectively reduced infarct volume, mitigate cerebral edema, and increased the mRNA and protein expression of basic ifbroblast growth factor and vascular endothe-lial growth factor at 24 hours of reperfusion. The effect was most signiifcant in the 13-methyltetradecanoic acid 40 and 80 mg/kg groups. The ifndings suggest that 13-methyltetradecanoic acid can relieve focal ischemia/reperfusion injury immediately after reperfusion, stimu-late the upregulation of basic ifbroblast growth factor and vascular endothelial growth factor to exert neuroprotective effects.     

Neuroprotection of Chrysanthemum indicum Linne against cerebral ischemia/reperfusion injury by anti-inflammatory effect in gerbils

In this study, we tried to verify the neuroprotective effect of Chrysanthemum indicum Linne(CIL) extract, which has been used as a botanical drug in East Asia, against ischemic damage and to explore the underlying mechanism involving the anti-inflammatory approach. A gerbil was given CIL extract for 7 consecutive days followed by bilateral carotid artery occlusion to make a cerebral ischemia/reperfusion model. Then, we found that CIL extracts protected pyramidal neurons in the hippocampal CA1 region(CA1) from ischemic damage using neuronal nucleus immunohistochemistry and Fluoro-Jade B histofluorescence. Accordingly, interleukin-13 immunoreactivities in the CA1 pyramidal neurons of CIL-pretreated animals were maintained or increased after cerebral ischemia/reperfusion. These findings indicate that the pre-treatment of CIL can attenuate neuronal damage/death in the brain after cerebral ischemia/reperfusion via an anti-inflammatory approach.     

Buyanghuanwu decoction promotes angiogenesis after cerebral ischemia/reperfusion injury：mechanisms of brain tissue repair

Buyanghuanwu decoction has been shown to protect against cerebral ischemia/reperfusion injury,but the underlying mechanisms remain unclear.In this study,rats were intragastrically given Buyanghuanwu decoction,15 m L/kg,for 3 days.A rat model of cerebral ischemia/reperfusion injury was established by middle cerebral artery occlusion.In rats administered Buyanghuanwu decoction,infarct volume was reduced,serum vascular endothelial growth factor and integrin αvβ3 levels were increased,and brain tissue vascular endothelial growth factor and CD34 expression levels were increased compared with untreated animals.These effects of Buyanghuanwu decoction were partially suppressed by an angiogenesis inhibitor(administered through the lateral ventricle for 7 consecutive days).These data suggest that Buyanghuanwu decoction promotes angiogenesis,improves cerebral circulation,and enhances brain tissue repair after cerebral ischemia/reperfusion injury.     

Anti-inflammatory properties of lipoxin A4 protect against diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury

Lipoxin A4 can alleviate cerebral ischemia/reperfusion injury by reducing the inflammatory reaction,but it is currently unclear whether it has a protective effect on diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury.In this study,we established rat models of diabetes mellitus using an intraperitoneal injection of streptozotocin.We then induced focal cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery for 2 hours and reperfusion for 24 hours.After administration of lipoxin A4 via the lateral ventricle,infarction volume was reduced,the expression levels of pro-inflammatory factors tumor necrosis factor alpha and nuclear factor-kappa B in the cerebral cortex were decreased,and neurological functioning was improved.These findings suggest that lipoxin A4 has strong neuroprotective effects in diabetes mellitus complicated by focal cerebral ischemia/reperfusion injury and that the underlying mechanism is related to the anti-inflammatory action of lipoxin A4.     

阿托伐他汀对大鼠脑缺血再灌注后梗死灶周围中性粒细胞浸润和核转录因子-κB表达水平的影响

目的 观察阿托伐他汀对大鼠脑缺血再灌注后梗死灶周围中性粒细胞浸润以及核转录因子-κB表达水平的影响。方法 采用常规尼龙线栓法制备SD大鼠脑缺血再灌注模型,并将大鼠随机分为假手术组、大脑中动脉阻断再灌注(Middle cerebral artery occlusion/reperfusion,MCAO/R)(对照)组和MCAO/R阿托伐他汀(治疗)组; 对照组和治疗组分别于脑缺血2 h再灌注3 h处死; 采用TTC染色测定脑梗死体积; 应用HE染色检查梗死灶周围中性粒细胞浸润; 应用免疫组化染色观察核转录因子-κB(Nuclear factor-κB,NF-κB)活性水平。结果 与对照组比较,治疗组脑梗死体积减小(P<0.01); 与对照组比较,治疗组再灌注3 h后梗死灶周围中性粒细胞明显减少(P<0.01); 与对照组比较,治疗组的脑组织NF-κB活性降低(P<0.01)。结论 阿托伐他汀对大鼠脑缺血再灌注后梗死灶周围中性粒细胞浸润有明显抑制作用; 阿托伐他汀可抑制大鼠脑缺血再灌注过程中的炎症反应,其机制可能与抑制NF-κB的激活有关。     

阿托伐他汀钙对实验性脑缺血MMP-9表达变化的影响

目的探讨阿托伐他汀钙对大鼠脑缺血再灌注后脑组织中MMP-9mRNA及蛋白表达的影响。方法采用大脑中动脉线栓法制备脑缺血再灌注模型,参考Longa5分制法在动物麻醉清醒后进行评分,应用原位杂交和免疫组化法检测MMP-9mRNA及蛋白表达。结果大鼠脑缺血再灌注后缺血脑组织中MMP-9mRNA和蛋白表达增加(P<0.01),24h达高峰;阿托伐他汀钙干预治疗后能减少缺血脑组织中MMP-9mRNA和蛋白表达(P<0.05);降低神经功能缺损评分(P<0.05)。结论阿托伐他汀钙能抑制大鼠脑缺血再灌注后脑组织中MMP-9mRNA及蛋白表达,减轻缺血再灌损伤。     

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.     

Protective effect of ginkgo proanthocyanidins against cerebral ischemia/reperfusion injury associated with its antioxidant effects

Proanthocyanidins have been shown to effectively protect ischemic neurons, but its mechanism remains poorly understood. Ginkgo proan-thocyanidins (20, 40, 80 mg/kg) were intraperitoneally administered 1, 24, 48 and 72 hours before reperfusion. Results showed that ginkgo proanthocyanidins could effectively mitigate neurological disorders, shorten infarct volume, increase superoxide dismutase activity, and de-crease malondialdehyde and nitric oxide contents. Simultaneously, the study on grape seed proanthocyanidins (40 mg/kg) conifrmed that different sources of proanthocyanidins have a similar effect. The neurological outcomes of ginkgo proanthocyanidins were similar to that of nimodipine in the treatment of cerebral ischemia/reperfusion injury. Our results suggest that ginkgo proanthocyanidins can effectively lessen cerebral ischemia/reperfusion injury and protect ischemic brain tissue and these effects are associated with antioxidant properties.     

Remifentanil postconditioning improves global cerebral ischemia-induced spatial learning and memory deficit in rats via inhibition of neuronal apoptosis through the PI3K signaling pathway

Global cerebral ischemia followed by reperfusion, which leads to extensive neuronal damage, particularly the neurons in the hippocampal CA1 region. Apoptosis is one of the major mechanisms that lead to neuronal death after cerebral ischemia and reperfusion. The neuroprotective effects of remifentanil preconditioning against cerebral ischemia/reperfusion injury have been recently reported. Here we investigated whether remifentanil postconditioning exerts neuroprotective effects against global cerebral ischemia/reperfusion injury in rats and its potential mechanisms. Global cerebral ischemia was performed via 10 min of four-vessel occlusion. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positive cells and expression of Bcl-2 and Bax in the hippocampal CA1 region were assessed after reperfusion. Morris water maze task was used to quantify spatial learning and memory deficits after reperfusion. We found remifentanil postconditioning markedly improved the spatial learning and memory as well as attenuated neuronal apoptosis in hippocampus caused by cerebral ischemia/reperfusion injury. In addition, remifentanil postconditioning enhanced the expression of anti-apoptotic gene Bcl-2 while suppressed the expression of pro-apoptotic gene Bax in hippocampal CA1 region. However, the neuroprotective effects of remifentanil postconditioning were abolished by pretreatment of the PI3K inhibitor LY294002. The results suggest that remifentanil postconditioning exhibits neuroprotective effects against global cerebral ischemia/reperfusion injury in rats, and its mechanisms might involve inhibition of neuronal apoptosis through the PI3K pathway.     

Pretreated quercetin protects gerbil hippocampal CA1 pyramidal neurons from transient cerebral ischemic injury by increasing the expression of antioxidant enzymes

Quercetin(QE; 3,5,7,3′,4′-pentahydroxyflavone), a well-known flavonoid, has been shown to prevent against neurodegenerative disorders and ischemic insults. However, few studies are reported regarding the neuroprotective mechanisms of QE after ischemic insults. Therefore, in this study, we investigated the effects of QE on ischemic injury and the expression of antioxidant enzymes in the hippocampal CA1 region of gerbils subjected to 5 minutes of transient cerebral ischemia. QE was pre-treated once daily for 15 days before ischemia. Pretreatment with QE protected hippocampal CA1 pyramidal neurons from ischemic injury, which was confirmed by neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, pretreatment with QE significantly increased the expression levels of endogenous antioxidant enzymes Cu/Zn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase in the hippocampal CA1 pyramidal neurons of animals with ischemic injury. These findings demonstrate that pretreated QE displayed strong neuroprotective effects against transient cerebral ischemia by increasing the expression of antioxidant enzymes.     

Hispidulin Protects Against Focal Cerebral Ischemia Reperfusion Injury in Rats

Focal cerebral ischemia is associated with ischemia/reperfusion (I/R) injury. Hispidulin is a flavonoid compound with a variety of pharmacological properties. The neuroprotective effects of hispidulin have not been fully elucidated. Herein, we demonstrated that pretreatment of animals with hispidulin improved the neurological outcomes and decreased the infarct size and brain edema in the cerebral focal I/R model. Mechanistically, we showed in vivo and in vitro that hispidulin exerted a protective effect against I/R injury by inducing the Nrf2 antioxidant pathway through modulation of AMPK/GSK3β signaling. Taken together, our results suggest that hispidulin may be a useful neuroprotective agent against ischemia/reperfusion (I/R) injury.     

Neuroprotective effect of Cerebralcare Granule after cerebral ischemia/reperfusion injury

Cerebralcare Granule(CG) improves cerebral microcirculation and relieves vasospasm,but studies investigating its therapeutic effect on cerebral ischemia/reperfusion injury are lacking.In the present study,we administered CG(0.3,0.1 and 0.03 g/m L intragastrically) to rats for 7 consecutive days.We then performed transient occlusion of the middle cerebral artery,followed by reperfusion,and administered CG daily for a further 3 or 7 days.Compared with no treatment,high-dose CG markedly improved neurological function assessed using the Bederson and Garcia scales.At 3 days,animals in the high-dose CG group had smaller infarct volumes,greater interleukin-10 expression,and fewer interleukin-1β-immunoreactive cells than those in the untreated model group.Furthermore,at 7 days,high-dose CG-treated rats had more vascular endothelial growth factor-immunoreactive cells,elevated angiopoietin-1 and vascular endothelial growth factor expression,and improved blood coagulation and flow indices compared with untreated model animals.These results suggest that CG exerts specific neuroprotective effects against cerebral ischemia/reperfusion injury.     

Neuroprotective effects of rutaecarpine on cerebral ischemia reperfusion injury**

Rutaecarpine,an active component of the traditional Chinese medicine Tetradium ruticarpum,has been shown to improve myocardial ischemia reperfusion injury.Because both cardiovascular and cerebrovascular diseases are forms of ischemic vascular disease,they are closely related.We hypothesized that rutaecarpine also has neuroprotective effects on cerebral ischemia reperfusion injury.A cerebral ischemia reperfusion model was established after 84,252 and 504 μg/kg rutaecarpine were given to mice via intraperitoneal injection,daily for 7 days.Results of the step through test,2,3,5-triphenyl tetrazolium chloride dyeing and oxidative stress indicators showed that rutaecarpine could improve learning and memory ability,neurological symptoms and reduce infarction volume and cerebral water content in mice with cerebral ischemia reperfusion injury.Rutaecarpine could significantly decrease the malondialdehyde content and increase the activities of superoxide dismutase and glutathione peroxidase in mouse brain.Therefore,rutaecarpine could improve neurological function following injury induced by cerebral ischemia reperfusion,and the mechanism of this improvement may be associated with oxidative stress.These results verify that rutaecarpine has neuroprotective effects on cerebral ischemia reperfusion in mice.     

Apelin-13 inhibits apoptosis and excessive autophagy in cerebral ischemia/reperfusion injury

Apelin-13 is a novel endogenous ligand for an angiotensin-like orphan G-protein coupled receptor, and it may be neuroprotective against cerebral ischemia injury. However, the precise mechanisms of the effects of apelin-13 remain to be elucidated. To investigate the effects of apelin-13 on apoptosis and autophagy in models of cerebral ischemia/reperfusion injury, a rat model was established by middle cerebral artery occlusion. Apelin-13(50 μg/kg) was injected into the right ventricle as a treatment. In addition, an SH-SY5 Y cell model was established by oxygen-glucose deprivation/reperfusion, with cells first cultured in sugar-free medium with 95% N2 and 5% CO2 for 4 hours and then cultured in a normal environment with sugar-containing medium for 5 hours. This SH-SY5 Y cell model was treated with 10–7 M apelin-13 for 5 hours. Results showed that apelin-13 protected against cerebral ischemia/reperfusion injury. Apelin-13 treatment alleviated neuronal apoptosis by increasing the ratio of Bcl-2/Bax and significantly decreasing cleaved caspase-3 expression. In addition, apelin-13 significantly inhibited excessive autophagy by regulating the expression of LC3 B, p62, and Beclin1. Furthermore, the expression of Bcl-2 and the phosphatidylinositol-3-kinase(PI3 K)/Akt/mammalian target of rapamycin(mTOR) pathway was markedly increased. Both LY294002(20 μM) and rapamycin(500 nM), which are inhibitors of the PI3 K/Akt/mTOR pathway, significantly attenuated the inhibition of autophagy and apoptosis caused by apelin-13. In conclusion, the findings of the present study suggest that Bcl-2 upregulation and mTOR signaling pathway activation lead to the inhibition of apoptosis and excessive autophagy. These effects are involved in apelin-13-induced neuroprotection against cerebral ischemia/reperfusion injury, both in vivo and in vitro. The study was approved by the Animal Ethical and Welfare Committee of Jining Medical University, China(approval No. 2018-JS-001) in February 2018.