Morphological and neuro-behavioral parallels in the rat model of stroke

Middle cerebral artery occlusion (MCAO) is widely used as a rat model of focal brain ischemia. Evaluation of brain damage often includes the morphological analysis of the injury area, MRI, and various scales which depend on functional tests, commonly known as neurological severity score (NSS). We determined the optimal number of NSS tests and assessed their capacity for non-invasive evaluation of brain ischemic injury in the rat MCAO model. 275 male Sprague-Dawley rats were randomly divided into five groups, given either permanent (p) MCAO or transient (t) MCAO using an uncoated 4-0 monofilament catheter or a silicone-coated monofilament. The rats’ neurological status was examined before and at 1 and 24 h following MCAO. The size of brain injury was then measured histologically and the extent of right cerebral hemisphere edema was calculated. We established a correlation between these tests and morphological data for brain injury. Adjusted R² of the prediction of total histology score was 0.7. The Hosmer-Lemeshow p-value of this model was 0.812 for total brain histology. For the brain edema the adjusted R² of the prediction model was 0.48. The Hosmer-Lemeshow p-value of this model was 0.558 for brain edema. Our methods of estimating infarct size produces reliable and well correlated results at 24 h and demonstrates to be an easy and quick way to assess infarct size soon after ischemic injury has occurred. The described method for neurological assessment could ultimately aid in assessing various treatment modalities in the early hours following stroke.     

Intranasal Dexamethasone Reduces Mortality and Brain Damage in a Mouse Experimental Ischemic Stroke Model

Neuroinflammation triggered by the expression of damaged-associated molecular patterns released from dying cells plays a critical role in the pathogenesis of ischemic stroke. However, the benefits from the control of neuroinflammation in the clinical outcome have not been established. In this study, the effectiveness of intranasal, a highly efficient route to reach the central nervous system, and intraperitoneal dexamethasone administration in the treatment of neuroinflammation was evaluated in a 60-min middle cerebral artery occlusion (MCAO) model in C57BL/6 male mice. We performed a side-by-side comparison using intranasal versus intraperitoneal dexamethasone, a timecourse including immediate (0 h) or 4 or 12 h poststroke intranasal administration, as well as 4 intranasal doses of dexamethasone beginning 12 h after the MCAO versus a single dose at 12 h to identify the most effective conditions to treat neuroinflammation in MCAO mice. The best results were obtained 12 h after MCAO and when mice received a single dose of dexamethasone (0.25 mg/kg) intranasally. This treatment significantly reduced mortality, neurological deficits, infarct volume size, blood–brain barrier permeability in the somatosensory cortex, inflammatory cell infiltration, and glial activation. Our results demonstrate that a single low dose of intranasal dexamethasone has neuroprotective therapeutic effects in the MCAO model, showing a better clinical outcome than the intraperitoneal administration. Based on these results, we propose a new therapeutic approach for the treatment of the damage process that accompanies ischemic stroke.Electronic supplementary materialThe online version of this article (10.1007/s13311-020-00884-9) contains supplementary material, which is available to authorized users.     

Treatment with an Angiopoietin-1 mimetic peptide promotes neurological recovery after stroke in diabetic rats

AimVasculotide (VT), an angiopoietin‐1 mimetic peptide, exerts neuroprotective effects in type one diabetic (T1DM) rats subjected to ischemic stroke. In this study, we investigated whether delayed VT treatment improves long‐term neurological outcome after stroke in T1DM rats.MethodsMale Wistar rats were induced with T1DM, subjected to middle cerebral artery occlusion (MCAo) model of stroke, and treated with PBS (control), 2 µg/kg VT, 3 µg/kg VT, or 5.5 µg/kg VT. VT treatment was initiated at 24 h after stroke and administered daily (i.p) for 14 days. We evaluated neurological function, lesion volume, vascular and white matter remodeling, and inflammation in the ischemic brain. In vitro, we evaluated the effects of VT on endothelial cell capillary tube formation and inflammatory responses of primary cortical neurons (PCN) and macrophages.ResultsTreatment of T1DM‐stroke with 3 µg/kg VT but not 2 µg/kg or 5.5 µg/kg significantly improves neurological function and decreases infarct volume and cell death compared to control T1DM‐stroke rats. Thus, 3 µg/kg VT dose was employed in all subsequent in vivo analysis. VT treatment significantly increases axon and myelin density, decreases demyelination, decreases white matter injury, increases number of oligodendrocytes, and increases vascular density in the ischemic border zone of T1DM stroke rats. VT treatment significantly decreases MMP9 expression and decreases the number of M1 macrophages in the ischemic brain of T1DM‐stroke rats. In vitro, VT treatment significantly decreases endothelial cell death and decreases MCP‐1, endothelin‐1, and VEGF expression under high glucose (HG) and ischemic conditions and significantly increases capillary tube formation under HG conditions when compared to non‐treated control group. VT treatment significantly decreases inflammatory factor expression such as MMP9 and MCP‐1 in macrophages subjected to LPS activation and significantly decreases IL‐1β and MMP9 expression in PCN subjected to ischemia under HG conditions.ConclusionDelayed VT treatment (24 h after stroke) significantly improves neurological function, promotes vascular and white matter remodeling, and decreases inflammation in the ischemic brain after stroke in T1DM rats.     

Delayed Decompressive Craniectomy Improves the Long-term Outcomes in Hypertensive Rats with Space-occupying Cerebral Infarction

Background and Purpose

No experimental data has been published on the long-term effects of decompressive craniotomy in hypertensive rats with space-occupying cerebral infarction. The aim of the present study was to investigate the efficacy of decompressive craniectomy in a middle cerebral artery occlusion (MCAO) model of hypertensive rats in a prolonged period.

Methods

Totally 92 stroke-prone renovascular hypertensive rats (RHRSP) were subjected to left MCAO by an endovascular occlusion technique. The decompressive craniectomy was performed on 26 RHRSP at 1 and 24 h after MCAO, respectively. Infarct volume, neurological performance, and mortality were evaluated at 1, 2, 4, and 8 weeks after MCAO.

Results

The mortality was reduced from 52.5% in controls to 7.7% and 23.1% in the rats underwent craniectomy at 1 and 24 h after MCAO, respectively (P < 0.05, respectively). All of the treated rats presented smaller infarct volume from 1 week to 8 weeks and better neurological performance at 4–8 weeks after MCAO compared to the controls (P < 0.05, respectively). The craniectomy at early stage was more effective than that at late stage in reducing infarct volume and improving neurological performances at 1 and 2 weeks (P < 0.05, respectively). However, there was no significant difference in infarct volume and neurological scores between the treated groups of rats at 4 and 8 weeks after MCAO (P > 0.05).

Conclusions

Although the early craniectomy is more effective than delayed craniectomy in improving short-term outcome, the latter has the similar beneficial effects as early craniectomy on long-term outcome in hypertensive rats with space-occupying cerebral infarction.     

头孢曲松钠对大鼠脑缺血损伤的保护作用及其机制

目的 探讨在大鼠局灶性脑缺血模型中应用头孢曲松钠对脑缺血损伤的保护作用及其相关机制.方法 制备Wistar大鼠局灶性脑缺血模型,并按随机数字表法分为单纯缺血组(MCAO组)、头孢曲松钠治疗组(MCAO+CTX组)和盐水对照组,其中MCAO+CTX组为缺血90min时给予头孢曲松钠200 mg/kg.缺血后24 h、48 h、7 d时对各组大鼠进行神经行为学评分和脑水肿程度测定,同时比较各组大鼠皮层和海马谷氨酸转运体功能的差异.结果 随着缺血时间延长,各组大鼠神经行为学评分逐渐提高;脑水肿在缺血后24 h、48 h时逐渐加重,至7 d时已逐渐消退.与MCAO组比较,各时间点MCAO+CTX组大鼠神经行为学评分明显提高,脑水肿程度明显减轻,伤侧皮层及海马谷氨酸转运体功能明显增强,差异均有统计学意义(P＜0.05).结论 头孢曲松钠对大鼠局灶性脑缺血损伤具有保护作用,其机制可能与增强谷氨酸转运体功能从而减轻谷氨酸神经毒性作用有关.

Abstract：

Objective To explore the neuroprotective effect of ceftriaxone on cerebral ischemia injury in rats with focal cerebral ischemia and its possible mechanism. Methods Focal cerebral ischemic models were established in Wistar rats and randomly divided into ischemic group (performed middle cerebral artery occlusion [MCAO]), ceftriaxone (CTX) therapy group (given CTX at a dosage of 200 mg/kg 90 min after MCAO) and control group (given physiological saline only). Twenty-four and 48 h, and 7 d after MCAO, neurological behaviors and cerebral edema level were evaluated in these 3 groups;glutamate transporter function in the cortex and hippocampus of rats was compared between each 2 groups. Results With time extended, neurological behaviors scores were obviously elevated in every group;and cerebral edema became worse at 24 and 48 h and decreased 7 d after MCAO. As compared with that in the ischemic group, glutamate transporter function, level of edema and neurological behaviors scores in cortex and hippocampus of rats in the CTX therapy group were statistically increased at different ischemic time points (P<0.05). Conclusion Ceftriaxone has a neuroprotective effect against focal cerebral ischemia in rats, which may relate to increased glutamate transporter function and reduced glutamate neurotoxicity.     

低氧预处理对大鼠脑缺血再灌注后梗死体积和血脑屏障通透性的影响

目的　探讨低氧预处理对大鼠脑缺血再灌注损伤的保护作用。方法　将SD大鼠分为 3组 ,即假手术组、缺血再灌注组、缺氧预处理 +缺血再灌注组。连续吸入 8%O2 +92 %N2 3h作缺氧预处理 ,12h后再经插线左大脑中动脉栓塞 (MCAO)制作缺血再灌注模型 ,到相应时间点后观察缺氧预处理对MCAO大鼠的行为、脑含水量、血脑屏障通透性和脑梗死体积的影响。结果与缺血再灌注组相比 ,缺氧预处理组大鼠的行为明显改善 ,脑伊文思蓝 (EB)含量、脑含水量 (P <0 0 5 ) ,脑梗死体积缩小。结论　低氧预处理降低缺血再灌注脑组织血脑屏障通透性 ,抑制脑水肿 ,缩小梗死体积 ,对缺血再灌注损伤具有保护作用     

Application of endovascular suture occlusion of middle cerebral artery in gerbils to obtain consistent infarction

Abstract

Middle cerebral artery occlusion (MCAO) by endovascular suture has gained increasing acceptance because it is relatively non-invasive and allows reperfusion. However, Its application in rats has resulted In inconsistent infarction volumes which involve only the subcortex or subcortex plus some cortex. In order to eliminate this drawback, we applied the intraluminal suture occlusion of MCA to gerbils that have an incomplete Circle of Willis. MCAO was induced by inserting an endovascular 5-0 nylon suture with a blunted tip into the Circle of Willis. Animals were divided into two groups: permanent MCAO for 24 h fn = 8) and transient MCAO for 3 h with 21 h reperfusion fn = 8). The corrected infarction volume in the permanent MCAO group was 232 ± 37 mm³ whereas it was 230 ± 45 mm³ in the transient MCAO group. All animals in both groups had infarction in both cortex and subcortex. Results of this study show that endovascular suture occlusion of MCA can be easily applied in gerbils to obtain consistent infarction. This would allow both transient and permanent focal ischemia to be tested in the same model of ischemia. [Neurol Res 1999; 21: 574–578]     

Effects of dexmedetomidine after transient and permanent occlusion of the middle cerebral artery in the rat

Summary. Increased sympathetic tone is a consequence of cerebral ischemia. Although the role of catecholamines in ischemic damage is still unclear, in some experimental ischemia models α₂-adrenergic agonism has proved to be neuroprotective. In the present work we have compared the effects of transient and permanent middle cerebral artery occlusion (MCAO) on the infarct volume, and, also, examined whether a selective α₂-adrenergic receptor agonist, dexmedetomidine (9 μg/kg or 15 μg/kg i.v.), is able to reduce ischemic damage after transient or permanent MCAO in rats. Permanent MCAO led to a significantly larger infarct volume than transient occlusion (p < 0.05). The rats receiving the higher dose of dexmedetomidine were detectected to have smaller (statistically non-significant) infarct volume in the cortex (30.9%) and in the striatum (20.3%) after transient occlusion. Additionally, dexmedetomidine caused significant variations in the physiological parameters. Received December 22, 1999; accepted September 20, 2000     

人参皂甙-Rd预先给药对大鼠脑的保护作用

目的探讨人参皂甙-Rd（Rd）预先给药对大鼠局灶性脑缺血再灌注损伤的保护作用。方法雄性SD大鼠70只,随机分为7组（n=10）,即缺血再灌注组（CON组）、Rd 5 mg组、Rd 10 mg组、Rd 20 mg组、Rd 40 mg组、Rd 80 mg组和丙二醇溶剂组（VEC组）。所有大鼠均采用右侧颈内动脉尼龙线栓法制作大脑中动脉阻塞（MCAO）模型,并于脑缺血前1 h分别经腹腔注射相应剂量Rd及丙二醇。于再灌注后24 h、48 h和72 h进行神经行为学评分（NBS）,并于72 h行2,3,5-氯化三苯基四氮唑（TTC）染色测量脑梗死容积百分比。结果与CON组和VEC组比较,Rd 5 mg组、Rd 10 mg组、Rd 20 mg组、Rd 40 mg组和Rd 80 mg组脑缺血再灌注后24 h、48 h、72 h神经行为学评分均较高,再灌注后72 h梗死容积均较低（P〈0.05）。Rd剂量小于40 mg/kg时,其保护效果随剂量的增加而增加。Rd 80 mg组与Rd 20 mg和Rd 40 mg组相比,NBS显著减小,脑梗死容积百分比明显升高（P〈0.05）;与Rd 5 mg组和Rd 10 mg组相比,NBS和脑梗死容积百分比均无明显差异（P〉0.05）。结论人参皂甙-Rd预先给药对大鼠短暂局灶性脑缺血再灌注损伤有保护作用,并在5-40 mg/kg之间存在剂量依赖性的保护作用。     

Neurovascular and neuronal protection by E64d after focal cerebral ischemia in rats

Calpains and cathepsins are two families of proteases that play an important role in ischemic cell death. In this study, we investigated the effect of E64d, a mu-calpain and cathepsin B inhibitor, in the prevention of neuronal and endothelial apoptotic cell death after focal cerebral ischemia in rats. Rats underwent 2 hr of transient focal ischemia from middle cerebral artery occlusion (MCAO) and were sacrificed 24 hr later. E64d (5 mg/ kg intraperitoneally) was administered 30 min before MCAO. Assessment included neurological function, infarction volume, brain water content, blood-brain barrier permeability, histology, and immunohistochemistry. The E64d-treated rats had significant brain protection against ischemic damage. We observed a reduction of infarction volume, brain edema, and improved neurological scores in E64d-treated rats compared with the nontreated control. Furthermore, there was a remarkable reduction in both proteases and caspase-3 activation and apoptotic changes in both neurons and endothelial cells in E64d-treated rats. These results suggest that E64d protects the brain against ischemic/reperfusion injury by attenuating neuronal and endothelial apoptosis.     

The asparaginyl endopeptidase legumain after experimental stroke

Various proteases in the brain contribute to ischemic brain injury. We investigated the involvement of the asparaginyl endopeptidase legumain after experimental stroke. On the basis of gene array studies and in situ hybridizations, we observed an increase of legumain expression in the peri-infarct area of rats after transient occlusion of the middle cerebral artery (MCAO) for 120 mins with a maximum expression at 24 and 48 h. Immunohistochemical analyses revealed the expression of legumain in Iba1⁺ microglial cells and glial fibrillary acidic protein-positive astrocytes of the peri-infarct area in mice after MCAO. Post-stroke recovery was also studied in aged legumain-deficient mice (45 to 58 weeks old). Legumain-deficient mice did not show any differences in physiologic parameters compared with respective littermates before, during MCAO (45 mins), and the subsequent recovery period of 8 days. Moreover, legumain deficiency had no effect on mortality, infarct volume, and the neurologic deficit determined by the rotating pole test, a standardized grip strength test, and the pole test. However, a reduced number of invading CD74⁺ cells in the ischemic hemisphere indicates an involvement in post-stroke inflammation. We conclude that legumain is not essential for the functional deficit after MCAO but may be involved in mechanisms of immune cell invasion.     

电针预处理对大鼠脑缺血再灌注损伤后EAAT2的表达研究

目的研究电针预处理对脑缺血再灌注损伤后大鼠缺血半暗带兴奋性谷氨酸转运体2(EAAT2)表达的影响,探讨EAAT2在电针预处理诱导脑缺血耐受中的作用。方法 18只SD雄性大鼠随机分为3组(n=6):分别为假手术(Sham)组、右侧大脑中动脉阻闭(MCAO)组、电针预处理(EA)组。假手术组仅分离血管,不进行阻闭,术后24 h检测;MCAO组用MCAO法致缺血120 min后于再灌注24 h检测;EA组大鼠予电针刺激30 min,刺激结束2 h后处理同MCAO组。3组大鼠在观察神经行为学变化后取材,通过2,3,5-氯化三苯四唑(TTC)染色评估梗死面积,并检测EAAT2 mRNA及蛋白表达水平。结果电针预处理能明显降低脑梗死容积百分比(P0.01),提高MCAO大鼠神经行为学评分,诱导脑缺血耐受并抑制脑缺血再灌注损伤后24 h EAAT2表达的下降(P0.01)。结论脑缺血再灌注损伤后,EAAT2表达下降,而电针预处理能显著抑制缺血半暗带EAAT2的表达下调,诱导脑缺血耐受,从而减轻脑缺血再灌注损伤。     

血红素氧合酶-1及血红素氧合酶-2在大鼠局灶性脑缺血中的意义

目的　研究血红素氧合酶 1(HO 1)及血红素氧合酶 2 (HO 2 )在局灶性脑缺血中的作用。方法　采用大鼠大脑中动脉栓塞脑缺血模型 ,对 6 6只大鼠脑缺血后不同时间点进行HO 1、HO 2免疫组化染色及病理学研究 ,并用计算机图像分析技术计算两者表达水平。结果　栓塞后 30min大鼠皮质及海马即有HO 1阳性神经元及胶质细胞的表达 ,且随着时间推移HO 1的表达逐渐增强 ,到栓塞后 12h达峰值 (P <0 0 1) ,以后逐渐下降 ,栓塞后 1周仍有HO 1表达。HO 2在正常大鼠及梗死大鼠脑组织内均有表达。栓塞后不同时间段 ,HO 2阳性神经元的数量无明显变化 (P >0 0 5 ) ,但HO 2表达呈动态变化 ,2 4h时最高 (P <0 0 1) ,以后逐渐下降。结论　脑缺血时脑内HO 1、HO 2表达的不同变化 ,是脑组织对损伤恢复重要的机制之一。HO 1修复受损的神经元和胶质细胞 ,而HO 2在于维护正常细胞的稳定     

Neuroprotective Effects by Nimodipine Treatment in the Experimental Global Ischemic Rat Model : Real Time Estimation of Glutamate

Objective

Glutamate is a key excitatory neurotransmitter in the brain, and its excessive release plays a key role in the development of neuronal injury. In order to define the effect of nimodipine on glutamate release, we monitored extracellular glutamate release in real-time in a global ischemia rat model with eleven vessel occlusion.

Methods

Twelve rats were randomly divided into two groups: the ischemia group and the nimodipine treatment group. The changes of extracellular glutamate level were measured using microdialysis amperometric biosensor, in coincident with cerebral blood flow (CBF) and electroencephalogram. Nimodipine (0.025 µg/100 gm/min) was infused into lateral to the CBF probe, during the ischemic period. Also, we performed Nissl staining method to assess the neuroprotective effect of nimodipine.

Results

During the ischemic period, the mean maximum change in glutamate concentration was 133.22±2.57 µM in the ischemia group and 75.42±4.22 µM (p<0.001) in the group treated with nimodipine. The total amount of glutamate released was significantly different (p<0.001) between groups during the ischemic period. The %cell viability in hippocampus was 47.50±5.64 (p<0.005) in ischemia group, compared with sham group. But, the %cell viability in nimodipine treatment group was 95.46±6.60 in hippocampus (p<0.005).

Conclusion

From the real-time monitoring and Nissl staining results, we suggest that the nimodipine treatment is responsible for the protection of the neuronal cell death through the suppression of extracellular glutamate release in the 11-VO global ischemia model of rat.     

Neuroprotection in ischemic stroke--combination drug therapy and mild hypothermia in a rat model of permanent focal cerebral ischemia

We have recently demonstrated marked neuroprotective efficacy of a combination therapy with magnesium (calcium- and glutamate-antagonist), tirilazad (antioxidant) and mild hypothermia (MTH) in a rat model of transient focal cerebral ischemia. In the present study, we investigated MTH under conditions of permanent focal cerebral ischemia. In part I, 20 Sprague-Dawley rats were subjected to 6 h of permanent, laser-Doppler flowmetry (LDF) controlled middle cerebral artery occlusion (MCAO). Drugs were administered 30 min before and 1 h after MCAO. Hypothermia (33 degrees C) was maintained for 2 h. Infarct size was planimetrically determined after 6 h. In part II, 29 rats were assigned to the same treatment arms and subjected to 7 days of permanent MCAO. Neurological deficits and body weight were assessed daily. Infarct size was determined on day 7. In part I, MTH significantly reduced infarct formation by 52% after 6 h. In part II, high mortality within the first 3 days was observed in both groups. Treated animals showed a significantly better postoperative weight gain on day 7 and neurological recovery on days 6 and 7 compared to controls without significant differences in infarct volume. MTH seems to exert its neuroprotective properties even in a setting of permanent cerebral ischemia. High mortality and absence of infarct reduction after 7 days might be due to model limitations. Neurological recovery, the most important clinical outcome parameter, is significantly improved in 7-day survivors. Significant neuroprotection under conditions of permanent ischemia and former promising results in transient ischemia justify further investigations of MTH.     

Protective role for type 4 metabotropic glutamate receptors against ischemic brain damage

We examined the influence of type 4 metabotropic glutamate (mGlu4) receptors on ischemic brain damage using the permanent middle cerebral artery occlusion (MCAO) model in mice and the endothelin-1 (Et-1) model of transient focal ischemia in rats. Mice lacking mGlu4 receptors showed a 25% to 30% increase in infarct volume after MCAO as compared with wild-type littermates. In normal mice, systemic injection of the selective mGlu4 receptor enhancer, N-phenyl-7-(hydroxyimino)cyclopropa[b]chromen-1a-caboxamide (PHCCC; 10 mg/kg, subcutaneous, administered once 30 minutes before MCAO), reduced the extent of ischemic brain damage by 35% to 45%. The drug was inactive in mGlu4 receptor knockout mice. In the Et-1 model, PHCCC administered only once 20 minutes after ischemia reduced the infarct volume to a larger extent in the caudate/putamen than in the cerebral cortex. Ischemic rats treated with PHCCC showed a faster recovery of neuronal function, as shown by electrocorticographic recording and by a battery of specific tests, which assess sensorimotor deficits. These data indicate that activation of mGlu4 receptors limit the development of brain damage after permanent or transient focal ischemia. These findings are promising because selective mGlu4 receptor enhancers are under clinical development for the treatment of Parkinson''s disease and other central nervous system disorders.     

硫酸镁在大鼠局灶脑缺血中的保护作用

目的 研究非竞争性谷氨酸受体拮抗剂－－硫酸镁在大鼠局灶脑缺血中的作用。方法 采用线栓法建立大鼠右侧大脑中动脉区永久脑缺血模型,分别于缺血前半小时,、缺血后第１、３、６、１２小时静滴１０％硫酸镁溶液,滴速１．５ｍｌ／ｈ,通过神经功能评分、梗死体积及含水量的改变、病理学检查,探讨硫酸镁对脑缺血的保护作用及治疗时间窗。结果 缺血６小时内应用硫酸镁能改善运动功能,减轻脑水肿,缩经体积。结论 硫酸镁具有明显     

Application of endovascular suture occlusion of middle cerebral artery in gerbils to obtain consistent infarction.

Middle cerebral artery occlusion (MCAO) by endovascular suture has gained increasing acceptance because it is relatively non-invasive and allows reperfusion. However, its application in rats has resulted in inconsistent infarction volumes which involve only the subcortex or subcortex plus some cortex. In order to eliminate this drawback, we applied the intraluminal suture occlusion of MCA to gerbils that have an incomplete Circle of Willis. MCAO was induced by inserting an endovascular 5-0 nylon suture with a blunted tip into the Circle of Willis. Animals were divided into two groups: permanent MCAO for 24 h (n = 8) and transient MCAO for 3 h with 21 h reperfusion (n = 8). The corrected infarction volume in the permanent MCAO group was 232 +/- 37 mm3 whereas it was 230 +/- 45 mm3 in the transient MCAO group. All animals in both groups had infarction in both cortex and subcortex. Results of this study show that endovascular suture occlusion of MCA can be easily applied in gerbils to obtain consistent infarction. This would allow both transient and permanent focal ischemia to be tested in the same model of ischemia.     

Anemonin Alleviates Nerve Injury After Cerebral Ischemia and Reperfusion (I/R) in Rats by Improving Antioxidant Activities and Inhibiting Apoptosis Pathway

In the present study, we aimed at evaluating the potential neuroprotective effect and the underlying mechanism of anemonin against cerebral ischemia and reperfusion (I/R) injury. Anemonin was administered to rats by the intraperitoneally (i.p.) route once daily for 7 days before middle cerebral artery occlusion (MCAO). Focal cerebral ischemia was induced by 90 min of MCAO followed by 24 h of reperfusion. After that, animals were sacrificed by decapitation, brain was removed, and various biochemical estimations, neurological status, and assessment of cerebral infarct size were carried out. MCAO followed by 24 h of reperfusion caused a significant increase in infarct size, neurological deficit score, malondialdehyde (MDA) content, reactive oxygen species (ROS) level, and DNA fragmentation, as well as a decrease in the activities of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), and Na⁺, K⁺-ATPase in the brain. Furthermore, elevated Bax expression, increased caspase-3 cleavage, and decreased Bcl-2 expression were observed in nontreated rats in response to focal cerebral I/R injury. However, pretreatment with anemonin significantly reversed these levels of biochemical parameters, reduced cerebral infarct size, and improved the neurologic score in cerebral ischemic animals. Additionally, a wide distribution of anemonin in plasma and brain tissues and the brain-to-plasma partition coefficient (Ri) ratio of 0.7 at 90 min indicated that this compound could penetrate the blood-brain barrier (BBB). These results showed that pretreatment with anemonin provided a significant protection against cerebral I/R injury in rats by, at least in part, its antioxidant action and consequent inhibition of apoptosis.     

脑缺血预处理及HSP70表达对大鼠脑梗死的保护作用

目的建立局灶性可重复性大鼠脑缺血动物模型,探讨蛋白合成在脑缺血预处理(PC)诱导脑缺血耐受(IT)中的作用。方法应用改进的Longa’s法建立局灶脑缺血(MCAO)模型,短暂性脑缺血20min作为PC,PC 后24h给予永久性MCAO(PMCAO),并与未进行PC者比较。免疫印记法测量PC后24h及给予蛋白合成抑制剂放线菌酮后HSP70的变化,PMCAO24h后观察脑梗死的大小,神经功能评分;同时观察在PC前或PC后PMCAO 前给予蛋白合成抑制剂放线菌酮对上述指标的影响。结果 PC后24h行PMCAO,脑梗死体积明显减小(P<0．01), 神经功能评分减低(P<0．05);PC前给予放线菌酮消除了以上影响,但在PC后较长时间而在PMCAO之前给予则没有以上影响;HSP70在PC后24h明显表达,而在PC前30min给予防线菌酮抑制了HSP70的表达。结论 PC能够通过减少脑组织损伤和神经功能缺损对之后发生的脑缺血产生脑保护作用。PC诱导脑缺血耐受有赖于新蛋白的合成。