左旋丁苯酞抗脑缺血缺氧作用研究

目的考察左旋丁苯酞注射液(l-butylphthalide,l-NBP)抗脑缺血缺氧作用。方法采用小鼠断头全脑缺血、密闭缺氧、颈总动脉及迷走神经结扎和大鼠中动脉阻塞等实验方法。结果 l-NBP 20、10和5 mg.kg-1剂量组可以明显延长小鼠断头后喘气时间和小鼠密闭缺氧的存活时间,可以降低大鼠中动脉阻塞后的脑梗死百分率;l-NBP 20、10 mg.kg-1剂量组可以明显延长小鼠颈总动脉及迷走神经结扎后的存活时间。结论 l-NBP具有一定的抗脑缺血缺氧作用。     

Effects of amelioration of total flavonoids from stems and leaves of Scutellaria baicalensis Georgi on cognitive deficits, neuronal damage and free radicals disorder induced by cerebral ischemia in rats

Previous studies reported that the total flavonoids from the stems and leaves of Scutellaria baicalensis Georgi (TFSS) could enhance and improve learning and memory abilities in experimental animals, and reduce the neuronal pathologic alterations induced by some reagents in mice. The present study examined whether TFSS can improve memory dysfunction, neuronal damage, and abnormal free radicals induced by permanent cerebral ischemia in rats. The permanent cerebral ischemic model in rats was produced by bilateral ligation of the common carotid arteries. The influence of permanent cerebral ischemia on learning and memory was determined in the Morris water maze. The neuronal damage in the hippocampus and cerebral cortex was assessed by the neuronal morphologic observations. The contents of malondialdehyde (MDA) and nitric oxide (NO), and the activities of superoxide dismutase (SOD) and catalase (CAT) in the hippocampus and cerebral cortex were measured using thiobarbituric acid, nitrate reductase, xanthine-xanthine oxidase, and ammonium molybdate spectrophotometric methods, respectively. In learning and memory performance tests, cerebral ischemic rats always required a longer latency time to find the hidden platform and spent a shorter time in the target quadrant in the Morris water maze. TFSS 17.5-70 mg.kg(-1) daily orally administered to ischemic rats for 20 d, from day 16-35 after operation differently reduced the prolonged latency and increased swimming time spent in the target quadrant. In neuronal morphologic observations, daily oral TFSS 17.5-70 mg.kg(-1) for 21 d, from day 16-36 after operation markedly inhibited the ischemia-induced neuronal damage. In addition, the increased contents of MDA and NO, and SOD activity, and the decreased activity of CAT in the hippocampus and cerebral cortex induced by cerebral ischemia were differently reversed. The reference drug piracetam (140 mg.kg(-1) per day for 20-21 d) similarly improved impaired memory and neuronal damage but had no significant effects on free radicals in ligated rats. TFSS can improve memory deficits and neuronal damage in rats after permanent cerebral ischemia, which may be beneficial in the treatment of cerebrovascular dementia.     

Caffeic acid ameliorates early and delayed brain injuries after focal cerebral ischemia in rats

AIM:To investigate the effects of caffeic acid on early and delayed injuries after focal cerebral ischemia in rats, and the possible relation to 5-lipoxygenase inhibition. METHODS: Transient focal cerebral ischemia was induced by middle cerebral artery occlusion in Sprague-Dawley rats. Caffeic acid (10 and 50 mg/kg) was ip injected for 5 d after ischemia. The brain injuries were observed, and the levels of cysteinyl leukotrienes and leukotriene B4 in the brain tissue were measured. RESULTS: Caffeic acid (50 mg/kg) ameliorated neurological dysfunction and neuron loss, and decreased infarct volume 24 h after ischemia; it attenuated brain atrophy, infarct volume, and particularly astrocyte proliferation 14 d after ischemia. In addition, it reduced the production of leukotrienes (5-lipoxygenase metabolites) in the ischemic hemispheres 3 h and 7 d after ischemia. CONCLUSION: Caffeic acid has protective effect on both early and delayed injuries after focal cerebral ischemia in rats; and this effect may partly relate to 5-lipoxygenase inhibition.     

Cilostazol, a phosphodiesterase 3 inhibitor, protects mice against acute and late ischemic brain injuries

Cilostazol, a selective inhibitor of phosphodiesterase 3, exerts neuroprotective effects on acute brain injury after cerebral ischemia in rats. However, it is unknown whether cilostazol affects the subacute or chronic ischemic injury. In the present study, we evaluated the dose- and time-dependent effects of cilostazol on acute ischemic brain injury and the long-lasting effect on the late (subacute/chronic) injury in mice with focal cerebral ischemia induced by transient middle cerebral artery occlusion. We found that pre-treatment of cilostazol (injected i.p. at 30 min before ischemia) significantly ameliorated the acute injury 24 h after ischemia, and the effective doses were 3-10 mg/kg. The post-treatment of cilostazol (10 mg/kg) was effective on the acute injury when it was injected 1 and 2 h after ischemia. In addition, for the late injury, post-treatment of cilostazol (10 mg/kg, i.p., for 7 consecutive days after ischemia) attenuated neurological dysfunctions, brain atrophy and infarct volume. It also inhibited astrocyte proliferation/glial scar formation and accelerated the angiogenesis in the ischemic boundary zone 7 and 28 days after ischemia. Thus, we conclude that cilostazol protects against not only the acute injury, but also the late injury in mice with focal cerebral ischemia; especially it can modify brain remodeling, astrogliosis and angiogenesis.     

黄芪提取物对大鼠全脑缺血再灌注和小鼠缺氧性损伤的保护作用

目的　研究黄芪提取物 (EA)对大鼠全脑缺血再灌注和小鼠缺氧性损伤的保护作用。方法　采用小鼠常压耐缺氧实验和小鼠断头实验 ,观察EA对小鼠耐缺氧能力的影响 ;采用大鼠四动脉结扎模型 ,观察EA对缺血再灌注大鼠脑水肿 ,脑组织中超氧化物歧化酶 (SOD)活性、丙二醛(MDA)含量 ,血浆和海马内皮素 (ET)及病理性改变的影响。结果　EA能延长常压耐缺氧实验小鼠的存活时间及快速断头后小鼠的张口喘气时间 ;EA能减轻缺血再灌注大鼠脑组织的水肿程度 ,提高SOD活性、降低MDA含量 ,降低血浆和海马ET的含量 ,减轻病理性损伤。结论　EA对脑缺血再灌注和缺氧性损伤有明显的保护作用 ,减轻全脑缺血模型大鼠的脑水肿和病理性损伤 ,其作用机制可能与EA抗氧化、降低ET含量有关     

Dehydroepiandrosterone sulfate prevents ischemia-induced impairment of long-term potentiation in rat hippocampal CA1 by up-regulating tyrosine phosphorylation of NMDA receptor

We have reported that dehydroepiandrosterone sulfate (DHEAS) reduces the threshold for long-term potentiation (LTP) in Shaffer collateral-CA1 synapses through the amplification of Src-dependent NMDA receptor signaling. The present study is a follow-up of the above reports, aiming at evaluating the effects of DHEAS on the impaired LTP in reversible forebrain ischemic rats. Transient (20 min) incomplete forebrain ischemia led to an impaired LTP in the hippocampal CA1 region without damages to the basal synaptic transmission between the Shaffer collaterals and pyramidal neurons. Repetitive administrations of DHEAS (20 mg/kg for 3 days) from the first 3 h of reperfusion, but not acute DHEAS application (50 microM), prevent the impairment of LTP produced by ischemia. Co-administration of the specific sigma(1) receptor antagonist NE100 with DHEAS completely prevented the protective effect of DHEAS. In contrast, progesterone (PRGO) not only had no protective effect against the ischemic LTP impairment, but also attenuated the protective effect of DHEAS on the impaired LTP. Tyrosine phosphorylation of NMDA receptor subunit 2B (NR2B) significantly decreased after ischemia, whereas that of NR1 had no obvious change. Furthermore, the repetitive administration of DHEAS improved the reduction in tyrosine phosphorylation of NR2B. These findings suggest that the repetitive activation of sigma(1) receptor induced by DHEAS might prevent the ischemic LTP impairment through regulating the tyrosine phosphorylation of NR2B.     

延胡索乙素对大鼠实验性心肌缺血的保护作用

目的 研究延胡乙素（dl-THP)对大鼠实验性心肌缺血的保护作用。方法 观察dl-THP对垂体后叶素（pit)所致大鼠心电图急性缺血性改变的预防作用以及对异丙肾上腺素（Iso)引起心肌损伤大鼠的保护作用。结果 dl-THP对垂体后叶素所致心电图改变有明显预防作用。能对抗Iso所致ECG的ST段升高。显著抑制心肌组织中磷酸肌激酶（CPK）、乳酸脱氢酶（LDH）的释放,降低血清CPK和LDH水平,保护心肌组织超氧化物歧化酶（SOD）活性,减少丙二醛（MDA）生成。结论 dl-THP对实验性心肌缺血有明显的保护作用。     

重组人促红细胞生成素鼻腔给药对大鼠慢性脑缺血的保护作用

目的：观察重组人促红细胞生成素（rhE-PO）鼻腔给药对大鼠慢性缺血性脑损伤的保护作用。方法：以大脑中动脉栓塞诱导大鼠局灶性脑缺血,手术当日术前30 min和术后2 h各给药一次,第2天起隔天一次,持续到术后14 d。缺血后1、3、7、14、21、283、5 d进行神经症状评分和斜板试验,缺血后35 d计算脑梗死体积和缺血周边区神经元密度。结果：rhEPO鼻腔给药（24、48 U）、依达拉奉和rhEPO腹腔给药（5000 U/kg）能改善缺血后神经症状评分,提高斜板角度,降低脑梗死体积,增加缺血侧周边区存活神经元密度。结论：rhEPO鼻腔给药对大鼠慢性缺血性脑损伤具有保护作用,其有效剂量范围较腹腔给药低。     

Chronic oleoylethanolamide treatment improves spatial cognitive deficits through enhancing hippocampal neurogenesis after transient focal cerebral ischemia

Oleoylethanolamide (OEA) has been shown to have neuroprotective effects after acute cerebral ischemic injury. The aim of this study was to investigate the effects of chronic OEA treatment on ischemia-induced spatial cognitive impairments, electrophysiology behavior and hippocampal neurogenesis. Daily treatments of 30 mg/kg OEA significantly ameliorated spatial cognitive deficits and attenuated the inhibition of long-term potentiation (LTP) in the middle cerebral artery occlusion (MCAO) rat model. Moreover, OEA administration improved cognitive function in a manner associated with enhanced neurogenesis in the hippocampus. Further study demonstrated that treatment with OEA markedly increased the expressions of brain-derived neurotrophic factor (BDNF) and peroxisome proliferator-activated receptors α (PPARα). Our data suggest that chronic OEA treatment can exert functional recovery of cognitive impairments and neuroprotective effects against cerebral ischemic insult in rats via triggering of neurogenesis in the hippocampus, which supports the therapeutic use of OEA for cerebral ischemia.     

Protective effects of acetyl-L-carnitine on neurodegenarative changes in chronic cerebral ischemia models and learning-memory impairment in aged rats

This study investigated the effects of acetyl-L-carnitine (ALC) in secondarily-induced cerebral chronic ischemia models using rats with permanent ligation of bilateral common carotid arteries (BCCL) and spontaneously hypertensive rats (SHR). Additionally, we used normal aged rats as a primary dementia model. Chronic ALC administration at 100 mg/kg (p.o.) for 4 weeks significantly attenuated neurodegenerative changes. In groups receiving 50 mg/kg or 100 mg/kg, ALC inhibited the active astrocyte increase in cerebral tissues of both BCCL and SHR models. In BCCL rats, ALC administration (50 mg/kg or 100 mg/kg, p.o.) resulted in significant promotion of glutathione levels in brain tissues. We also confirmed behavioral improvement after ALC treatment (100 mg/kg for 8 weeks, p.o.) on learning-memory function using aged rats (18 months old) in a passive avoidance task and preservation of CA1 pyramidal neurons was coincided on histopathological observation. In conclusion, chronic ALC administration may ameliorate cerebral ischemia progress after a cerebrovascular disorder as well as spontaneous ageing-related cerebral dysfunction via hippocampal protection.     

白芍总苷对全脑缺血再灌损伤的保护作用

目的　研究白芍总苷 (TGP)对全脑缺血再灌损伤的保护作用及其作用机制。方法　采用大鼠三血管阻断全脑缺血再灌损伤模型 ,观察大鼠眼球颜色、脑组织SOD活性、MDA含量及病理组织学变化。结果　TGP(10、2 0、4 0mg·kg-1)可以明显改善大鼠眼球颜色的变化 ;TGP(2 0mg·kg-1)能提高脑缺血再灌大鼠大脑皮层、海马、纹状体中降低的SOD活性 ,并且降低升高的MDA含量 ;TGP(2 0mg·kg-1)对大鼠缺血性脑组织的病理组织学改变具有较好的保护作用。结论　TGP对缺血再灌注脑损伤具有明显的保护作用 ,此作用可能与其抗氧化有关。     

Effects of ibudilast on hippocampal long-term potentiation and passive avoidance responses in rats with transient cerebral ischemia.

The present study evaluated the effects of ibudilast on impaired passive avoidance responses and hippocampal long-term potentiation (LTP) caused by transient cerebral ischemia in rats. The hippocampal nerve cell density was also measured. The latency determined in retention trials of passive avoidance shortened significantly in the 4-vessel occlusion (4VO) group (in which four blood vessels were occluded for 20 min to cause cerebral ischemia). A significant recovery in the latency was observed by administration of ibudilast (10 mg kg (-1)). The population spike amplitude in both the hippocampal CA1 region and perforant path-dentate gyrus synapses was potentiated by tetanus stimulation in the sham-operated group, while in the 4VO group, LTP was significantly inhibited. This inhibition was reversed by administration of ibudilast (10 mg kg (-1)). A marked reduction of cell densities in the CA1 region was observed in the 4VO group compared with the normal group. The nerve cell density in the hippocampal CA1 region was decreased by 20 min of cerebral ischemia. Ibudilast significantly inhibited the reduction of cell densities in a dose-dependent manner. In contrast, the cell density in the dentate gyrus was comparable in the 4VO and normal groups, and no significant changes were observed in the ibudilast groups. These findings suggest that ibudilast might possess neuronally protective properties, i.e. protecting neurons not only from deaths but also from functional damage due to certain cerebral ischemia.     

Enalapril and moexipril protect from free radical-induced neuronal damage in vitro and reduce ischemic brain injury in mice and rats.

Angiotensin-converting enzyme inhibitors have been demonstrated to protect spontaneously hypertensive rats from cerebral ischemia. The present study investigated the protective effect of enalapril and moexipril in models of permanent focal cerebral ischemia in normotensive mice and rats. To elucidate the mechanism of neuroprotection the influence of these angiotensin-converting enzyme inhibitors on glutamate-, staurosporine- or Fe2+/3+-induced generation of reactive oxygen species and neuronal cell death in primary cultures from chick embryo telencephalons was studied. Treatment with moexipril or enalapril dose-dependently reduced the percentage of damaged neurons, as well as mitochondrial reactive oxygen species generation induced by glutamate, staurosporine or Fe2+/3+. Furthermore, moexipril and enalapril attenuated staurosporine-induced neuronal apoptosis as determined by nuclear staining with Hoechst 33258. In mice, 1 h pretreatment with enalapril (0.03 mg/kg) or moexipril (0.3 mg/kg) significantly reduced brain damage after focal ischemia as compared to control animals. Additionally, moexipril (0.01 mg/kg) was able to reduce the infarct volume in the rat model after focal cerebral ischemia. The results of the present study indicate that the angiotensin-converting enzyme inhibitors enalapril and moexipril promote neuronal survival due to radical scavenging properties.     

注射用刺五加对脑缺血的保护作用

目的研究注射用刺五加对小鼠全脑缺血及对大鼠不完全脑缺血的保护作用。方法小鼠尾静脉给予饱和氯化镁溶液 0 1mL ,形成全脑缺血模型 ,观察注射用刺五加对小鼠张口喘气维持时间的影响 ;结扎大鼠双侧颈总动脉及迷走神经形成急性实验性不完全脑缺血模型 ,观察药物对大鼠缺血后脑含水量、脑指数及乳酸脱氢酶增加的抑制影响。结果注射用刺五加 ( 1 4 8mg/kg)能显著延长小鼠张口喘气时间 ,对小鼠全脑缺血有保护作用 ;注射用刺五加 ( 80mg/kg)能显著抑制大鼠脑含水量、脑指数及乳酸脱氢酶的增加。结论注射用刺五加具有抗脑缺血作用     

Different neuroprotective responses of Ginkgolide B and bilobalide, the two Ginkgo components, in ischemic rats with hyperglycemia

Ginkgo biloba extracts show neuroprotective effects during cerebral ischemia, but with various components, the mechanisms of action remain unclear. In this study, we tested the effects of Ginkgolide B (GB) and bilobalide (BB) on normoglycemic and hyperglycemic rats subjected to transient cerebral ischemia. Rats were administered p.o. with different Ginkgo components GB (6 mg/kg) or BB (6 mg/kg) once daily for 7 days. Hyperglycemia was made by jugular vein infusion of glucose and transient middle cerebral artery occlusion/reperfusion was induced by a suture insertion technique. Results showed that both GB and BB exerted neuroprotection under normoglycemia, as determined by infarct volume and neurological deficit scores. Yet, BB showed less protective effects during hyperglycemic cerebral ischemia. Cerebral blood flow (CBF) was evaluated during occlusion and the first hour of reperfusion. BB but not GB caused acute increase in CBF after reperfusion, especially in hyperglycemia. Reactive oxygen species and malondialdehyde levels were reduced by GB in both models but BB were not effective in reactive oxygen species or malondialdehyde control in hyperglycemia ischemic rats. These results suggested that CBF plays crucial roles during early stage of reperfusion in the presence of hyperglycemia. Administration of compound that improves CBF may have little effect in hyperglycemic stroke.     

Antiplatelet and antithrombotic activity of L-3-n-butylphthalide in rats

3-n-butylphthalide (NBP) is a potentially beneficial drug for the treatment of ischemic stroke with multiple actions on different pathophysiological processes. In the present study, the effect of l-, d-, and dl-NBP was investigated on ADP-, collagen-, and AA-induced platelet aggregation. l-NBP was the most potent among l-, d-, and dl-NBP. At higher concentration the effect of dl-NBP on platelet aggregation was greater than that of l- or d-NBP alone. The ex vivo antiaggregatory activity of l-NBP 100mg/kg declined gradually after 2 hours, but a considerable antiplatelet activity was still observed 4h after l-NBP administration. NBP was given orally and resulted in a dose-dependent inhibition of thrombus formation. Of the two isomers, l-NBP was the most potent. It significantly protected mice from a mixture of collagen and epinephrine induced thromboembolic death. When 100 mg/kg of l-NBP were administered orally to rats, the bleeding time increased 2.1-fold compared with the control group. At the same dose, ex vivo platelet aggregation induced by ADP, collagen, and AA was inhibited by l-NBP and the antithrombotic effects of the compound were also observed. Thus, NBP exerts oral anti-platelet and anti-thrombotic efficacy without perturbing systemic hemostasis in rats. l-NBP is more potent than d- and dl-NBP as antiplatelet agent.     

苯妥英钠对大鼠脑缺血再灌注后脑内Fas表达的抑制作用

目的观察脑缺血再灌注后Fas基因在脑内的表达及苯妥英钠对其的影响。方法采用夹闭大鼠双侧颈总动脉的急性前脑缺血再灌注模型和免疫组织化学染色法。结果脑缺血再灌注后神经细胞过度地表达Fas,尤以缺血半暗带明显,且Fas表达分布广泛;苯妥英钠给药组(30、60mg/kg)Fas阳性细胞的表达数显著低于不给药的生理盐水对照组(P<0.01),且两剂量组之间差异无统计学意义。结论①苯妥英钠对缺血再灌注脑损伤有保护作用;②苯妥英钠拮抗缺血再灌注脑损伤的机制与其抑制Fas表达从而减少缺血诱导的神经细胞凋亡有关。     

Protective effect of DM-9384, a novel pyrrolidone derivative, against experimental cerebral anoxia

The protective effects of DM-9384 [N-(2,6-dimethylphenyl)-2-(2-oxo- 1-pyrrolidinyl) acetamide] against cerebral anoxia were investigated using various animal models. Oral administration of DM-9384 resulted in a significant prolongation of survival time in mice and rats subjected to the normobaric hypoxia; its minimal effective doses were 30 and 10 mg/kg, respectively. A significant protection by this drug against hypobaric hypoxia, histotoxic anoxia and cerebral ischemia also occurred in mice at a dose of 100 mg/kg, p.o. Bifemelane (100-300 mg/kg, p.o.) was protective against these models except for hypobaric hypoxia, and the effects of piracetam, aniracetam and pramiracetam (1000 mg/kg, p.o.) were variable depending on the type of anoxia model used. DM-9384 (100 mg/kg and lower) attenuated the hypolocomotion and the disturbance of cerebral energy metabolism such as a decrease in ATP, an increase in lactate and lactate/pyruvate ratio induced by hypoxia in rats. The spontaneous motor activity, uptake and utilization of brain glucose in normal animals, however, were not influenced by this drug. Based on these results, DM-9384 is characterized as a broad spectrum anti-anoxic drug with negligible CNS depression, and the cerebral protective effect of this drug may be, at least in part, attributable to its ability to improve the cerebral energy metabolic disturbance.     

Lithium regulates hippocampal neurogenesis by ERK pathway and facilitates recovery of spatial learning and memory in rats after transient global cerebral ischemia

Recent studies have demonstrated that lithium has a neuroprotective effect against brain ischemia. Whether this effect is mediated by hippocampal neurogenesis remains unknown. The ERK (extracellular signal-regulated kinase) pathway plays an essential role in regulating neurogenesis. The present study was undertaken to investigate whether lithium regulates hippocampal neurogenesis by the ERK pathway and improves spatial learning and memory deficits in rats after ischemia. Rats were daily injected with lithium (1 mmol/kg) and 2 weeks later subjected to 15-min ischemia induced by four-vessel occlusion method. 5-bromo-2'-deoxyuridine (Brdu; 50mg/kg) was administrated twice daily at postischemic day 6, or for 3 days from postischemic day 6 to 8. We found that lithium increased the ERK1/2 activation after ischemia by western blotting analysis. There was a significant increase in Brdu-positive cells in the hippocampal dentate gyrus after lithium treatment, compared with ischemia group at postischemic days 7 and 21; furthermore, the survival rate of Brdu-positive cells was elevated by lithium. Inhibition of the ERK1/2 activation by U0126 diminished these effects of lithium. The percentages of Brdu-positive cells that expressed a neuronal marker or an astrocytic marker were not significantly influenced by lithium. Moreover, lithium improved the impaired spatial learning and memory ability in Morris water maze, and U0126 attenuated the behavioral improvement by lithium. These results suggest that lithium up-regulates the generation and survival of new-born cells in the hippocampus by the ERK pathway and improves the behavioral disorder in rats after transient global cerebral ischemia.     

丁基苯酞对大脑中动脉阻断后皮层组织中花生四烯酸释放及磷脂酶A2基因表达的影响

目的　研究丁基苯酞 (dl NBP) ,d NBP和l NBP对大脑中动脉阻断 (MCAO) 6h后缺血区皮层中花生四烯酸 (AA)释放及磷脂酶A2 (PLA2 )基因表达的影响。方法　阻断大脑中动脉起始部造成局灶性脑缺血模型。HPLC检测AA。Northernblot检测皮层中PLA2 基因表达。结果　MCAO后 6h ,皮层中AA释放明显增加。于脑缺血后 5min和 12 0min ,给dl NBP(10或 2 0mg·kg- 1)和尼莫地平 (0 5mg·kg- 1)可显著抑制AA的释放。d NBP和l NBP作用比较 ,显示d NBP有与dl NBP相似的作用 ,而l NBP则无明显影响。Northern印迹结果表明 ,脑缺血 6h ,皮层中PLA2 的基因表达增强。dl NBP和d NBP(10 ,2 0mg·kg- 1,ip)皆可使表达降低 ,而l NBP对缺血脑组织中PLA2 的基因表达的升高无明显影响。结论　dl NBP和d NBP可抑制MCAO后脑组织中AA释放和PLA2 的基因表达。