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

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

Expression profiles of microRNAs after focal cerebral ischemia/reperfusion injury in rats

Rat models of focal cerebral ischemia/reperfusion injury were established by occlusion of the middle cerebral artery. Microarray analysis showed that 24 hours after cerebral ischemia, there were nine up-regulated and 27 down-regulated microRNA genes in cortical tissue. Bioinformatic analysis showed that bcl-2 was the target gene of microRNA-384-5p and microRNA-494, and caspase-3 was the target gene of microRNA-129, microRNA-320 and microRNA-326. Real-time PCR and western blot analyses showed that 24 hours after cerebral ischemia, bcl-2 mRNA and protein levels in brain tissue were significantly decreased, while caspase-3 mRNA and protein levels were significantly increased. This suggests that following cerebral ischemia, differentially expressed microRNA-384-5p, microRNA-494, microRNA-320, microRNA-129 and microRNA-326 can regulate bcl-2 and caspase-3 expression in brain tissue.

A feasible strategy for focal cerebral ischemiareperfusion injury: remote ischemic postconditioning

It is difficult to control the degree of ischemic postconditioning in the brain and other isch- emia-sensitive organs. Remote ischemic postconditioning could protect some ischemia-sensitive organs through measures on terminal organs. In this study, a focal cerebral ischemia-reperftlsion injury model was established using three cycles of remote ischernic postconditioning, each cycle consisted of 10-minute occlusion of the femoral artery and 10-minute opening. The results showed that, remote ischemic postconditioning significantly decreased the percentage of the in- farct area and attenuated brain edema. In addition, inflammatory nuclear factor-KB expression was significantly lower, while anti-apoptotic Bcl-2 expression was significantly elevated in the ce- rebral cortex on the ischemic side. Our findings indicate that remote ischemic postconditioning attenuates focal cerebral ischemia/reperfusion injury, and that the neuroprotective mechanism is mediated by an anti-apoptotic effect and reduction of the inflammatory response.

Electroacupuncture preconditioning protects against focal cerebral ischemia/reperfusion injury via suppression of dynamin-related protein 1

Electroacupuncture preconditioning at acupoint Baihui （GV20） can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1 （Drp1） can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20 （depth 2 mm, intensity 1 mA, frequency 2/15 Hz, for 30 minutes, once a day）. Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.

Neuroprotective effect of ischemic preconditioning in focal cerebral infarction: relationship with upregulation of vascular endothelial growth factor

Neuroprotection by ischemic preconditioning has been confirmed by many studies, but the precise mechanism remains unclear. In the present study, we performed cerebral ischemic pre- conditioning in rats by simulating a transient ischemic attack twice （each a 20-minute occlusion of the middle cerebral artery） before inducing focal cerebral infarction （2 hour occlusion-reper- fusion in the same artery）. We also explored the mechanism underlying the neuroprotective effect of ischemic preconditioning. Seven days after ocdusion-reperfusion, tetrazolium chloride staining and immunohistochemistry revealed that the infarct volume was significantly smaller in the group that underwent preconditioning than in the model group. Furthermore, vascular endothelial growth factor immunoreactivity was considerably greater in the hippocampal CA3 region of preconditioned rats than model rats. Our results suggest that the protective effects of ischemic preconditioning on focal cerebral infarction are associated with upregulation of vascu- lar endothelial growth factor.

Effects of Fujian tablet on Nogo-A mRNA expression and plasticity of the corticospinal tract in a rat model of focal cerebral ischemia

The present study investigated the effects of Fujian tablet, a Chinese medicine compound that can nourish liver and kidney, on corticospinal tract plasticity and cervical cord microenvironment in rats with focal cerebral ischemia. Results showed that motor function of rats with right proximal middle cerebral artery occlusion was significantly improved following treatment with Fujian tablet, 9 g crude drug/kg. Anterograde tracing revealed significantly increased biotinylated dextran amine expression in the denervated （left） side of the cervical cord （C4-6） following Fujian tablet treatment, and significantly decreased Nogo-A mRNA expression was detected in the denervated side of the cervical cord （C4-6） using in situ hybridization. Pearson＇s correlation analysis showed a negative correlation between biotinylated dextran amine and Nogo-A mRNA expression （r = -0.943, P 〈 0.01）. Results demonstrated that Fujian tablet can promote corticospinal tract plasticity possibly through the inhibitory effect on Nogo-A mRNA expression in the cervical spinal cord, thereby improving motor dysfunction.

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

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

Effect of ephrin-B2 on the expressions of angiopoietin-1 and-2 after focal cerebral ischemia/reperfusion

Ephrin-B2 has been shown to participate in angiogenesis, but the underlying mechanisms involved remain unclear. In this study, a rat model of local cerebral ischemia was prepared by focal middle cerebral artery occlusion, followed by 24-hour reperfusion. Then, ephrin-B2 protein was administered intracerebroventricularly for 3 consecutive days via a micro-osmotic pump. Western blot assay and quantitative real-time reverse transcription PCR demonstrated the expression levels of angiopoietin-1 （Ang-1） mRNA and protein in the penumbra cortex of the ephrin-B2 treated group were decreased at day 4 after reperfusion, and increased at day 28, while the expression levels of angiopoietin-2 （Ang-2） were highly up-regulated at all time points tested. Double immunofluorescent staining indicated that Ang-1 and Ang-2 were both expressed in vascular endothelial cells positive for CD31. These findings indicate that ephrin-B2 influences the expressions of Ang-1 and Ang-2 during angiogenesis following transient focal cerebral ischemia.

Effect of Xingnaojing Injection(醒脑静注射液)on Hippocampal N-methyl-D-aspartic Acid Receptors of Focal Cerebral Ischemia in Rats

Objective: To observe and elucidate the neuroprotective effect of Xingnaojing (XNJ) injection on hippocampal N-methyl-D-aspartic acid (NMDA) receptors of focal cerebral ischemia in rats. Methods: Cerebral ischemia was established by occluding the middle cerebral artery with an intraluminal suture technique in rats. Neurological deficit score, infarct volume and quantity of NMDA receptors were estimated in all groups and compared. Results: After being treated with XNJ, the score decreased in the initial 6 hours and infarct volume decreased in 24 hours. And within 24 hours, the quantity of NMDA receptors obviously decreased compared with the model group (P<0. 01) It indicated that XNJ could ameliorate neurological behavior of middle cerebral artery occlusion rats and down-regulate the expression of hippocampal NMDA receptors. Conclusion: The neuroprotective effect of XNJ on focal cerebral ischemia is possibly related to down-regulating the expression of NMDA receptors in rats.

Therapeutic window of Qingkailing injection for focal cerebral ischemia/reperfusion injury

The time window in which a drug is effective varies between drugs. The present study investigated the therapeutic window of Qingkailing injection for focal cerebral ischemia/reperfusion in mice. Animals underwent middle cerebral artery occlusion and were injected with Qingkailing （1.5, 3, 6 mL/kg）. Infarct volume and neurological function were assessed after 24 hours of ischemia. In addition, to establish the therapeutic time window, mice were injected with 3 mL/kg Qingkailing at 0, 1, 3, 4, 6, 9 and 12 hours after occlusion. Results revealed that Qingkailing injection significantly reduced infarct volume and improved neurological function in model mice after cerebral infarction for up to 9 hours, demonstrating that the therapeutic window of Qingkailing injection can extend to 9 hours for cerebral ischemia/reperfusion in mice.

Baicalin and jasminoidin effects on gene expression and compatibility in the hippocampus following focal cerebral ischemia

The compound traditional Chinese medicine Qingkailing, which is an ingredient used to treat cerebral ischemia, has been limited to studies concerning single genes or single pathways. Interactions and pharmacological mechanisms of the compound ingredients （baicalin and jasminoidin） remain poorly understood. In the present study, baicalin and jasminoidin, as well as the combination, were used to separately treat mouse models of cerebral ischemia, cDNA microarray analyses of 374 cerebral ischemia-related genes were utilized to determine changes in gene-expression profiles. Arraytrack 3.40 and Ingenuity Pathway Analysis （IPA） databases were utilized to analyze changes in gene molecular functions and network path functions. Baicalin or jasminoidin alone effectively reduced infarct area, and the combination resulted in significantly better outcomes. IPA showed inhibited cell apoptosis in the baicalin group and Ca^2＋ channel regulation in the jasminoidin group. The combination of baicalin and jasminoidin activated HTR3A and F5 expression, regulated Ca^2＋ channels, activated kappa light polypeptide gene enhancer inhibitor IKBKG in B cells to control IkB kinase/nuclear factor-kB cascade, suppressed activation of inflammatory cytokine interleukin-6 receptors and activated transduction of guanine-nucleotide- binding protein （G protein） signal. Results suggested that the combination of baicalin and jasminoidin resulted in similar molecular mechanisms to baicalin and jasminoidin alone. However, novel pharmacological actions of compatibility were detected, demonstrating significant protection against cerebral ischemia.

Effect of restraint stress on depression-like behaviors in rats after transient focal cerebral ischemic injury

BACKGROUND： Restraint stress is a typical psychophysiological stressor. Simulating the early passion and difficulty in walking of patients after attack of stroke meets onset features.OBJECTIVE： To evaluate the effect of restraint stress on depression-like behaviors in rats after transient focal cerebral ischemic injury, and to investigate the feasibility for its being as modeling method of depression model after stroke.DESIGN： A randomized controlled animal experiment.SETTING： Department of Clinical Medicine, Faculty of Aerospace Medicine of the Fourth Military Medical University of Chinese PLA.MATERIALS： Forty-eight male Sprague-Dawley rats, weighing 240 - 270 g, provided by the Experimental Animal Center of the Fourth Military Medical University of Chinese PLA were used in the current study.METHODS： The experiments were carried out in the Faculty of Aerospace Medicine of the Fourth Military Medical University of Chinese PLA between August 2005 and August 2006. ①Experiment intervention： The rats were randomized into middle cerebral artery occlusion-reperfusion （MCAO） ＋stress group, simple MCAO group, sham-operation ＋ stress group and simple sham-operation group, with 12 rats in each group.Rats in the first two groups were developed into cerebral ischemia/reperfusion models by suture-occluded method. Rats in the MCAO＋stress group were modeled and restraint stress scheme was performed. At week 5 after modeling, the rats were placed in self-made restraining tubes, 2 hours/time, once a day, for 2 successive weeks. The common carotid artery, external and internal carotid arteries of rats in the latter two groups were exposed. The stress way of sham-operation＋ stress group was the same as that of MCAO＋ stress group. ②The neurological status grading and motor performance evaluation （screen test, rota-rod test and balance beam test） were conducted in rats with simple sham-operation group and MCAO group before, 1st and 28^th days after modeling. Depression-like behavior test was performed in the rats of each group by sucrose preference test and open field test at the end of the experiment.MAIN OUTCOME MEASURES： Changes of depression-like behaviors of rats in each group.RESULTS： Forty-eight rats were involved in the experiment. Two rats with meningeal irritation sign were excluded from simple MCAO group, and one rat in the MCAO＋stress group died of some unclear causes during the experiments. The other 45 rats entered the stage of finial analysis. ① Depression-like behavior assessment results： The rats in the MCAO＋ stress group had a significantly decreased preference for sucrose solution, crossing and rearing scores, and increased immobility duration after the 14-day restraint stress,compared with those in other three groups （all P〈0.05）. ②The neurological status grading and motor performance evaluation： There were significant differences in the two indexes of rats in the simple MCAO group before, 1^st and 28^th days after modeling （P〈0.01）, while there was no significant difference before and 28^th days after modeling （P〉0.05）. There were no significant changes in sham-operation group at each time point （P〉0.05）.CONCLUSION： After being exerted restraint stress, the rats with transient focal ischemic injury may show obvious depression-like behaviors. Therefore, restraint stress can be used as a novel animal modeling method for further studying biological mechanism in central nervous system of post-stroke depression animals.

Changes in secretory pathway Ca^(2+)-ATPase 2 following focal cerebral ischemia/reperfusion injury

This study aimed to investigate changes in secretory pathway Ca2＋-ATPase 2 expression following cerebral ischemia/reperfusion injury, and to define the role of Ca2＋-ATPases in oxidative stress. A rat model of cerebral ischemia/reperfusion injury was established using the unilateral middle cerebral artery occlusion method. Immunohistochemistry and reverse transcription-PCR assay results showed that compared with the control group, the expression of secretory pathway Ca2＋-ATPase 2 protein and mRNA in the cerebral cortex and hippocampus of male rats did not significantly change during the ischemic period. However, secretory pathway Ca2＋-ATPase 2 protein and mRNA expression reduced gradually at 1, 3, and 24 hours during the reperfusion period. Our experimental findings indicate that levels of secretory pathway Ca2＋-ATPase 2 protein and mRNA expression in brain tissue change in response to cerebral ischemia/reperfusion injury.

An Early Continuous Experimental Study on Magnetic Resonance Diffusion-weighted Image of Focal Cerebral Ischemia and Reperfusion in Rats

Summary： The chronological and spatial rules of changes during focal cerebral ischemia and reperfusion in different brain regions with magnetic resonance diffusion-weighted imaging （DWI） in a model of occlusion of middle cerebral artery （MCAO） and the development of cytotoxic edema in acute phase were explored. Fifteen healthy S-D rats with MCA occluded by thread-emboli were randomly divided into three groups. 15 min after the operation, the serial imaging was scanned on DWI for the three groups. The relative mean signal intensity （RMSI） of the frontal lobe, parietal lobe, lateral cauda-putamen, medial cauda-putamen and the volume of regions of hyperintense signal on DWI were calculated. After the last DWI scanning, T2WI was performed for the three groups. After 15 rain ischemia, the rats was presented hyperintense signals on DWI. The regions of hyperintense signal were enlarged with prolonging ischemia time. The regions of hyperintense signal were back to normal after 60 min reperfusion with a small part remaining to show hyperintense signal. The RMSIs of parietal lobe and lateral cauda-putamen were higher than that of the frontal lobe and medial cauda-putamen both in ischemia phase and recanalization phase. The three groups were normal on T2WI imaging. DWI had good sensitivity to acute cerebral ischemia, which was used to study the chronological and spatial rules of development of early cell edema in ischemia regions.

Hyperlipidemia affects neuronal nitric oxide synthase expression in brains of focal cerebral ischemia rat model

BACKGROUND： Hyperlipidemia, a risk factor for ischemic cerebrovascular disease, may mediate production of neuronal nitric oxide synthase （nNOS） to induce increased nitric oxide levels, resulting in brain neuronal injury. OBJECTIVE： To investigate effects of hyperlipidemia on brain nNOS expression, and to verify changes in infarct volume and pathology during reperfusion, as well as neuronal injury following ischemia/reperfusion in a rat model of focal cerebral ischemia. DESIGN, TIME AND SETTING： Complete, randomized grouping experiment was performed at the Laboratory of Physiology, Shanxi Medical University from March 2005 to March 2006. MATERIALS： A total of 144 eight-week-old, male, Wistar rats, weighing 160-180 g, were selected. A rat model of middle cerebral artery occlusion was established by suture method after 4 weeks of formulated diet. Nitric oxide kit and rabbit anti-rat nNOS kit were respectively purchased from Nanjing Jiancheng Bioengineering Institute, China and Wuhan Boster Biological Technology, Ltd., China. METHODS： The rats were equally and randomly divided into high-fat diet and a normal diet groups. Rats in the high-fat diet group were fed a high-fat diet, consisting of 10% egg yolk powder, 5% pork fat, and 0.5% pig bile salt combined with standard chow to create hyperlipidemia. Rats in the normal diet group were fed a standard rat chow. A total of 72 rats in both groups were randomly divided into 6 subgroups： sham-operated, 4-hour ischemia, 4-hour ischemia/2-hour reperfusion, 4-hour ischemia/4-hour reperfusion, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion, with 12 rats in each subgroup. MAIN OUTCOME MEASURES： nNOS expression was measured by immunohistochemistry, and pathomorphology changes were detected by hematoxylin-eosin staining. Infarct volume and nitric oxide levels were respectively measured using 2, 3, 5-triphenyltetrazolium chloride （TTC） and immunohistochemistry. RESULTS： In the ischemic region, pathology changes were significant in the 4-hour ischemia/4-hour, 4-hour ischemia/6-hour reperfusion, and 4-hour ischemia/12-hour reperfusion subgroups fed on a high-fat diet compared to the same groups fed on a normal diet. In each ischemia subgroup, nNOS expression in brain tissues was higher than in the sham-operated subgroups fed on either the high-fat diet or normal diet （P 〈 0.01）. At each ischemia/reperfusion time point, rats fed on a high-fat diet expressed higher levels of nNOS compared to rats fed on the normal diet （P 〈 0.05）. When tissue was stained with TTC, a white infarction area was detected in the ischemic hemisphere, demonstrating that the infarct volume gradually increased with prolonged reperfusion time in each ischemia subgroup. At each ischemia/reperfusion time point, the infarct volume was larger in rats fed on a high-fat diet compared to those fed on a normal diet. CONCLUSION： nNOS expression was greater in hyperlipidemia rats following ischemia/reperfusion. Cerebral ischemia/reperfusion injury is aggravated with prolonged reperfusion time.

Effect of tetramethylpyrazine on the spatial learning and memory function of rats after focal cerebral ischemia

BACKGROUND： Tetramethylpyrazine （TMP） presents the effect of anti-platelet aggregation, reduces arteria resistance, increases cerebral blood flow, and improves microcirculation. OBJECTIVE： To observe the effects of TMP on the learning and memory abilities and the number of neurons in cortex and hippocampus after focal cerebral ischemia in rats DESIGN： A randomized controlled tria SETTING： Department of Human Anatomy and Histological Embryology, School of Medicine, Xi＇an Jiaotong University. MATERIALS： Fifty adult male Sprague-Dawley rats, weighing 250-300 g were supplied by the Experimental Animal Center, School of Medicine, Xi＇an Jiaotong University. TMP was purchased from Wuxi Seventh Pharmaceutical Co.Ltd （Lot Number： 2004051106, Specification： 2 mL/piece）. METHODS ： The experiments were carried out in School of Medicine of Xi＇an Jiaotong University from June 2004 to May 2005. The 50 rats were randomly divided into five groups according to the random number table method： sham-operated group, cerebral ischemia control group, low-dose TMP group, middle-dose TMP group and high-dose TMP group, 10 rats in each group. Rats in the TMP groups were immediately treated with intraperitoneal injection of TMP of 40, 80 and 120 mg/kg respectively, and those in the sham-operated group and cerebral ischemia control group were injected intraperitoneally by isovolume saline, once a day for 14 days successively. On the 15^th day, the spatial learning and memory abilities of the rats were assessed with the Morris water maze test, and then the changes of neuron numbers in cortex and hippocampus were observed by Nissl staining of brain sections. MAIN OUTCOME MEASURES ： The results of Morris water maze test and the changes of neuron numbers in cortex and hippocampus by Nissl staining of brain sections were observed. RESULTS： Finally 39 rats were involved in the analysis of results, and the other 11 died of excessive anesthesia or failure in model establishment. ① The rats in the cerebral ischemia control group manifested obvious spatial cognitive deficits in the place navigation trial and spatial probe trial. The mean values of escape latency in the sham-operated group, low, middle and high-dose TMP groups were obviously shorter than that in the cerebral ischemia control group [（23.92±2.21）, （41.84±3.74）, （39.50 ±3.80）, （31.38_±3.72）, （61.60±3.61） s, P 〈 0.05-0.01]. In the spatial probe trial, significant differences in the percentage of time spending in the former platform quadrant and frequency of crossing the former platform site in the sham-operated group, lose, middle and high-dose TMP groups were obviously higher or more than those in the cerebral ischemia control group [（36.27±3.42） %, （35.84±2.54）%, （38.43±3.08）%, （36.51±1.96）%, （22.24±3.46）%; （11 ±1 ）, （10±1）, （8_±1）, （8±1）, （4±1） times, P 〈 0.01]. ② In the morphological observation, the numbers of neurons in ipsilateral （left） parietal cortex in the sham-operated group, low, middle and high-dose TMP groups were obviously more than that in the cerebral ischemia control group [（98±8）, （65±5）, （53±6）, （57±6）, （37±6）/0.625 mm^2, P 〈 0.01], but the number of neurons in left hippocampus had no obvious differences among the groups （P 〉 0.05）. CONCLUSION ： TMP can improve obviously the spatial learning and memory function after permanent focal cerebral ischemia in rats, and the neuroprotective role of the drug in cortex may be involved in its mechanism.

Spatiotemporal expression of Nogo-66 receptor after focal cerebral ischemia

Ng R, the receptor for the neurite outgrowth inhibitor Nogo-66, plays a critical role in the plasticity and regeneration of the nervous system after injury such as ischemic stroke. In the present study, we used immunohistochemistry to investigate the regional expression of Ng R in rat brain following middle cerebral artery occlusion（MCAO）. Ng R protein expression was not observed in the center of the lesion, but was elevated in the marginal zone compared with control and sham-operated rats. The cerebral cortex and hippocampus（CA1, CA2, and CA3） showed the greatest expression of Ng R. Furthermore, Ng R expression was higher in the ipsilesional hemisphere than on the control side in the same coronal section. Although time-dependent changes in Ng R expression across brain regions had their own characteristics, the overall trend complied with the following rules： Ng R expression changes with time showed two peaks and one trough; the first peak in expression appeared between 1 and 3 days after MCAO; expression declined at 5 days; and the second peak occurred at 28 days.

An Experimental Proton Magnetic Resonance Spectroscopy Analysis on Early Stage of Acute Focal Cerebral Ischemia

U sing different m odels of focal cerebral ischemia,the temporal and spatial rules of m etabolism and energy changes in the post- ischem ia brain tissue were measured by proton m agnet- ic resonance spectroscopy(1 HMRS) to provide valuable inform ation for judging the prognosis of a- cute focal cerebral ischemia and carrying out effective therapy.Nine healthy Sprague- Dawly rats (both sexes) were randomly divided into two groups:The rats in the group A(n=4 ) were occlud- ed with self- thrombus for1h;The rats in the group B(n=5 ) were occluded with thread- em boli for1h.The 1 H MRS at30 ,4 0 ,5 0 ,6 0 min respectively was examined and the m etabolic changes of NAA,Cho and L ac in the regions of interest were sem iquantitatively analyzed. The spectrum intregral calculus area ratio of NAA,Cho,L ac to Pcr+Cr was setas the criterion.The values of NAA· Cho in the regions of interest were declined gradually within 1h after ischem ia, especially,the ratio of Cho/ (Pcr+Cr) ,NAA/ (Pcr+Cr) at6 0 m in had significant difference with that at5 0 min(P<0 .0 5 ) .The ratio of L ac/ (Pcr+Cr) began to decrease at4 0 min from initial in- crease of L ac in both A and B groups.MR proton spectrum analysis was a non- invasive,directand com prehensive tool for the study of cellular metabolism and the status of the biochemical energy in acute ischem ia stroke.

REAL-TIME MONITORING OF MITOCHONDRIAL FUNCTION AND CEREBRAL BLOOD FLOW FOLLOWING FOCAL ISCHEMIA IN RATS

Focal ischemia due to reduction of cerebral blood flow(CBF),creates 2 zones of damage:the core area,which suffers severe damage,and penumbra area,which surrounds the core and suffers intermediate levels of injury.Objectives:A novel method is introduced,which evaluates mitochondrial function in the core and in the penumbra,during focal cerebral ischemia.Methods:Wistar rats underwent focal cerebral ischemia by middle cerebral artery occlusion(MCAO)for 60 minutes,followed by 60 minutes of reperfusion.Mitochondrial function was assessed by a unique Multi-Site—Multi-Parametric(MSMP)monitoring system,which measures mitochondrial NADH using fluorometric technique,and CBF using Laser Doppler Flowmetry(LDF).Results:At the onset of occlusion,CBF dropped and NADH increased significantly only in the right hemisphere.CBF levels were significantly lower and NADH significantly higher in the core than in the penumbra.After reperfusion,CBF and NADH recovered correspondingly to the intensity of ischemia.Conclusion:Application of the MSMP system can add significant information for the understanding of the cerebral metabolic state under ischemic conditions,with an emphasis on mitochondrial function.

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.