Neuroprotective effects of Ginkgo biloba extract and Ginkgolide B against oxygen-glucose deprivation/reoxygenation and glucose injury in a new in vitro multicellular network model / 医学前沿

Acute ischemic stroke (AIS), as the third leading cause of death worldwide, is characterized by its high incidence, mortality rate, high incurred disability rate, and frequent reoccurrence. The neuroprotective effects of Ginkgo biloba extract (GBE) against several cerebral diseases have been reported in previous studies, but the underlying mechanisms of action are still unclear. Using a novel in vitro rat cortical capillary endothelial cell-astrocyte-neuron network model, we investigated the neuroprotective effects of GBE and one of its important constituents, Ginkgolide B (GB), against oxygen-glucose deprivation/reoxygenation and glucose (OGD/R) injury. In this model, rat cortical capillary endothelial cells, astrocytes, and neurons were cocultured so that they could be synchronously observed in the same system. Pretreatment with GBE or GB increased the neuron cell viability, ameliorated cell injury, and inhibited the cell apoptotic rate through Bax and Bcl-2 expression regulation after OGD/R injury. Furthermore, GBE or GB pretreatment enhanced the transendothelial electrical resistance of capillary endothelial monolayers, reduced the endothelial permeability coefficients for sodium fluorescein (Na-F), and increased the expression levels of tight junction proteins, namely, ZO-1 and occludin, in endothelial cells. Results demonstrated the preventive effects of GBE on neuronal cell death and enhancement of the function of brain capillary endothelial monolayers after OGD/R injury in vitro; thus, GBE could be used as an effective neuroprotective agent for AIS/reperfusion, with GB as one of its significant constituents.

Pharmacological functional MRI on regional cerebral responses to central analgesics / 中国医学影像技术

Objective To investigate the regional cerebral stimulation after central analgesics nasal spray and its mechanism with pharmacological functional magnetic resonance imaging (phfMRI). Methods Eighteen healthy right-handed volunteers participated. Butorphanol tartrate nasal spray was used as the experiment agent. Ethological experiment was carried out to record the participants' subjective feeling and the onset time of the analgesics, followed by the functional MRI (fMRI) scan two weeks later. Block design was adopted. Two phases of fMRI scan were performed at 7 min and 25 min after the nasal spray, respectively. Participants were also given pain stimulation in the dorsum of hand during the fMRI scanning. The data were post-processed with Matlab 6.5 and SPM 2. Results ①Onset time of butorphanol tartrate was 15-35 min after nasal spray administration, which was consistent with its concentration-time curve. ②After nasal spray, activations were observed in the cerebral cortex, including frontal lobe (orbitofrontal gyrus, medial frontal gyrus, superior frontal gyrus), temporal lobe (insula, middle temporal gyrus, inferior temporal gyrus), parietal lobe (precuneal gyrus), limbic system (anterior cingulate gyrus, middle cingulate gyrus, hippocampus, parahippocampal gyrus);subcortical region (globus pallidus) and cerebellum (6-9 of cerebellar cortex, cerebellar peduncle, vermis). ③The number and activation intensity of the second phase were more obvious than those of the first phase (P<0.01). Conclusion The feasibility of phfMRI study on cerebral stimulation and the mechanism of nasal spray is demonstrated. The study of butorphanol tartrate further validates the main distribution of opioid receptors in the central nervous system and the possible mechanism of central analgesia.

Neuroprotective effect of extract of Ginkgo biloba against excitotoxicty compared with ginkgolide B in neuron cell of rat / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effect of the extract of Ginkgo biloba (EGb761) and the components isolated from the extract named ginkgolide B (GB) against damage of glutamate in pretreatment modes so that determine their application value and approach.</p><p><b>METHOD</b>Based on glutamate-induced excitotoxicity to primary cultures from neonatal Sprague-Dawley (SD) rat hippocampal neuron, our experiment utilized trypan blue, TUNEL and LDH to study the effect of EGb761 and GB on neuron in different doses pretreatment modes, as well as to compare with the NMDA receptor uncompetitive antagonist-MK-801.</p><p><b>RESULT</b>EGb761 and GB can recrease cell viability, reduce apoptosis rate and decrease LDH leakage in different degree and depended on dose in certain range. The maximal protection was achieved at a concentration of 100 mg x L(-1), 100 micromol x L(-1), but inferior to MK-801 (10 micromol x L(-1)). The protective effect of GB is superior to EGb761.</p><p><b>CONCLUSION</b>Treatment with EGb761 and GB could protect the neurons against glutamate-induced injury. The maximal protection of GB was achieved by pretreatment is superior to EGb761, so its precautionanary intervention to high-risk population could have more value.</p>

Evaluation of the protective function of NO precursor/donator on cerebral ischemia injury with DWI and PWI / 中国医师杂志

Objective To establish a rat model of middle cerebral artery occlusion (MCAO)by blockage or obstruction of middle cerebral artery. NO precursor L-Arginine (L-ARG) and NO donator Nitroglycerine (NG)are administrated from intraearotid arteries. DWI and PWI are applied to evaluate blood circulation and brain damage of the effected region to elucidate the piotective function of L-ARG and NG in the early stage of brain ischemia. Methods The middle cerebral artery was occluded by insertion of a suture through the internal carotid artery of SD male rats to duplicate ischemia-reperfusion model. Reperfusion was established by suture withdrawal. After 2 hours of blockage, reperfusion and administrate L-ARG,NG by interventional therapy through the internal carotid artery simultaneously. Image indexes such as T1WI, T2WI, DWI and PWI are utilized to assess the changes in different time points. These indexes, Longa score and TTC stain were compared. Results There were obvious decrease in DWI high signal region and Trc pale region in drugs groups, compared with MCAO group(P＜0.01).ADC and rADC values in DWI high signal region increased gradually from 2 hours after ischemia to 24 hours after reperfusion in each group. ADC and rADC values in DWI high signal region of the drugs groups increased obviously(P＜0.01).Conclusion Interventional therapy with NO precursor/donator showed significant protective function in the early stage of brain ischemia.

The effects of early exercises intervention for nervous movement functional recovery on neonate hypoxic ischemic encephalopathy / 中国医师进修杂志

Objective To investigate the assistant method for improving and promoting nervous movement functional recovery on neonate hypoxie ischemic encephalopathy. Methods Eighty-five patients with neonate hypoxic ischemic encephalopathy were divided into two groups: observed group (45 cases) and control group(40 cases). Observed group added early exercises intervention on basis of routine synthetic drug treatment, compared to control group which just purely synthetic drug treatment with neonatal behavior neurological assessment (NBNA), mental development index (MDI) and psychomotor development index (PDI). Results NBNA at 14 days [(38.84±1.56)scores] in observed group was significantly higher than that in control group [(36.12±2.23)scores]. PDI at 6, 12 months and MDI at 12 months in observed group were significantly higher than those in control group. Conclusion Early exercises intervention can promote nervous movement functional recovery on neonate hypoxic ischemic encephalopathy, prevent or lessen brain injury sequels, elevate life quality for patients with neonate hypoxic ischemic encephalopathy.

MODULATORY EFFECT OF CAFFEINE ON GABA-ACTIVATED CURRENT FROM ACUTELY ISOLATED RAT DORSAL ROOT GANGLION NEURONS / 神经解剖学杂志

Whole-cell patch clamp technique was performed on acutely isolated rat dorsal root ganglion (DRG) neurons to investigate the modulatory effect of caffeine on γ-aminobutyric acid (GABA)-activated currents (IGABA). The results showed that the majority of the neurons examined (97.4%, 113/116) were sensitive to GABA. 1-1000 μmol/L GABA activated a concentration-dependent inward current which manifested obvious desensitization. After the neurons were treated with caffeine (0.01-100 μmol/L) prior to the application of GABA (100 μmol/L) for 30 s, GABA-activated membrane currents were obviously inhibited. Caffeine shifted the GABA dose-response curve downward and decreased the maximum response to 57% without changing Kd value. These results indicate that the inhibitory effect is non-competitive. Theophylline showed a similar and stronger inhibitory effect on IGABA. The pretreatment with caffeine (10 μmol/L) inhibited IGABA, which was potentized by diazepam (1 μmol/L). Intracellular application of H-8 almost completely abolished the inhibitory effect of caffeine on IGABA. The present results suggest that caffeine may be able to antagonize the effect of presynaptic inhibition of GABA in primary afferent.

Effects of interventional administration of L-Arginine or nitroglycerin on acute local cerebral ischemia in rats / 基础医学与临床

Objective To observe the effects of treating acute ischemic stroke in rats with interventional administration of nitric oxide precurcer L-Arginine or nitric oxide donor nitroglycerin.Methods The right middle cerebral arteries of rats were occluded by insertion of a suture to duplicate ischemia-reperfusion models.Forty-two male SD rats were randomly divided into four groups: MCAO group(n=12);sham operation group(n=6);NG group(n=12) and L-ARG group(n=12),intracarotid arteries administrated respectively by NS、NS、NG and ARG.Each of the four groups were subdivided into 2 groups according to the reperfusion time(3 h and 24 h),measurement of Longa scores,NO2-/NO3-in serum,HE staining and immunohistochemical(SABC)method were utilized to assess the changes of ischemic brain tissues in different groups.Results OX-42 positive cells of cortex and CA3 area of hippocampal: OX-42 positive cells were found,their features identified at 3 h after reperfusion.24 h the response of microglias was obvious,the number of the cells increased(P

Anti-NR_1 monoclonal antibody inhibits the glutamate-induced intracellular free calcium increase in rat hippocampal neurons / 基础医学与临床

Objective To study the effect of mAbN1,a monoclonal antibody against N-methyl-D-aspartate receptor subunit 1(NR1)on Ca2+ influx after glutamate stimulation in cultured rat hippocampal neurons.Methods Excitotoxicity was induced by glutamate in cultured hippocampal neurons.Confocal laser scanning microscopy was used to observe the changes in intracellular free calcium concentration([Ca2+]i)at the level of cultured hippocampal neurons following pretreatment with mAbN1 and MK-801.Intracellular free calcium was imaged after loading cells with the fluorescent dye indicator fluo-3/AM.Results Our findings indicate that as compared with MK-801,mAbN1 can more significantly attenuate the glutamate-induced [Ca2+]i increase,and it has no effect on [Ca2+]i in physiological condition.Conclusion mAbN1 may alter the secondary structure of NR,consequently influence Ca2+ influx in excitotoxicity process.

Development of excitotoxicity model with primary hippocampal neurons and implications of viability essay / 中华检验医学杂志

Objective To study the injury and protective action of drugs on neurons, the model of glutamate excitotoxicity on primary cultured hippocampual neurons from new born rats were( set up. Methods)By use of trypan blue dye staning and testing the lactate dehydrogenase leakage from cultured neurons, to investigate the neuron survival rate. Results We found the injury of neurons was related with the concentration of glutamate. NMDAR non-competitive antagonist —MK-801 could protect the glutamate excitotoxic damage on neurons. Conclusion The glutamate results in neuron injury through NMDAR; the model of neuron culture was sufficient for glutamate-induced excitotoxicity.

Effect of L-arginine or L-nitroarginine on kainic acid induced seizure and expression of iNOS mRNA in the rats' hippocampus / 中国药理学通报

AIM To observe the expression of inducible nitric ox ide synthase (iNOS) in the rats' hippocampus of kainic acid (KA) induced-seizur es and the effect of L-arginine(L-Arg) or L-nitroarginine(L- NNA) chronic intervention before KA. METHODS The expression of iN OS mRNA by RT-PCR and behaviour were observed after administration of convulsan t dose of KA (10 mg?kg -1 ) and pretreatment with NO predecessor (L-Ar g, 40 mg?kg -1 ) or a inhibitor of NOS(L-NNA, 50 mg?kg -1 ) befo re KA. RESULTS The time-dependent seizures were induced on rats after giving KA, and were improved and serious in the animals with L-NNA pr etreatment, but they were alleviated by L-Arg pretreatment before KA. Compa red with control, iNOS mRNA expression was feebly at KA 3 h, continuative improv ement accompanying KA time prolonged, and it was markedly enhanced at KA 24 h. I t couldn't be examined at KA 2 d or 3 d, and was obviously improved at KA 7 d a gain. iNOS mRNA appeared weak in the rats hippocampus with L-Arg pretreatme nt after KA 1 h, whereas it wasn't found in L-NNA pretreatment animals. CONCLUSION iNOS mRNA expression appeared in the hippocampus of seizu re rats at a few time after KA, and L-Arg chronic intervention before KA ha s a little effect on it.

Neuroprotective effects of nGBE against glutamate excitotoxicity / 中国临床药理学与治疗学

AIM:To investigate protective effects of novel extract of Ginkgo biloba(nGBE) in different administration modes on glutamate-induced neuronal damage.METHODS: The values of Essential nGBE were obtained by supercritical CO_2 fluid extraction.Based on glutamate excitotoxicity of primary cultures from neonatal Wistar rats hippocampal,by use of Trypan blue dye staining,testing the lactate dehydrogenase leakage from cultured neurons and terminal deoxynucleotidyl transferase-mediated nick end labeling(TUNEL) method,we examined glutamate-induced necrosis and apoptosis.The protective effects of nGBE in different administration modes(pre-treatment and post-treatment) were adopted and compared with the NMDA receptor uncompetitive antagonist MK-801 in acute-treatment.RESULTS:Treatment with nGBE in two administration modes all could increase ratio of surviving neuron,decrease LDH efflux and reduce ratio of neuron apoptosis in different degree,and the benefit of pre-treatment was superior to post-treatment,but inferior to MK-801.CONCLUSION:The extracts of Ginkgo biloba used nowadays in cerebrovascular disease as post-treatment have no prominent effect as far as their mechanism of antiexcitotoxicity.However they may have more value if they were used for precautionary intervention in high-risk population.

Correlations between serum C-reactive protein level and severity of disease and outcome in cerebral infarction / 临床神经病学杂志

Objective To investigate correlation between serum C-reactive protein (CRP) level and severity of disease and outcome in cerebral infarction (CI).Methods Ninety patients with CI within onset of 2 weeks were evaluated by National Institutes of Health Stroke Scale (NIHSS) and Barthel index (BI) at admission and 3 months later. Serum CRP level were measured at admission. Correlation analysis was performed between serum CRP level and NIHSS, BI scores.Results The patients were divided into group A [( 1.23?0.32)mg/L], group B [( 5.04?1.93) mg/L]and group C [( 25.34?14.27)mg/L] according to different serum CRP level. Serum CRP level correlated significantly with severity and outcome at admission and 3 months later ( r=0.40, 0.42, -0.55,-0.44,respectively, all P

Expression of IL-6 in kainic acid-induced seizure and regulation roles of nitric oxide pathway / 中国药理学通报

AIM To explore the role of nitric oxide (NO) mediators in seizure behavior and the related expression of interlukin 6(IL 6). METHODS The IL 6 immunoreactivity (IL 6 ir) and behaviour were observed in kainic acid (KA) induced seizure following pretreatment with L nitroarginine( L NNA), a inhibitor of nitric oxide synthase(NOS), or the same number of moles of L arginine( L Arg). RESULTS The results showed that time dependent seizures were induced on animals after administration of KA (10 mg?kg -1 ), accompanied by the immediate enhancement of IL 6 ir in hippocampal structure, piriform area and cortex. The behaviors of rats were not markedly altered by chronic pretreatment with L NNA (50 mg?kg -1 ) or L Arg (40 mg?kg -1 ). However, after the administration of KA, the seizure behaviors were obviously different in the group of L NNA and L Arg respectively. Seizure was agrevated in the animals with L NNA pretreatment and many rats died at KA 3 hours, whereas seizure was alleviated after KA in the group of L Arg. IL 6 expression was apparently up regulated in some brain areas such as hippocampus in the group of KA pretreated with L NNA, but opposite effects appeared in the group pretreated with L Arg before KA injection. CONCLUSION These results indicate that endogenous NO mediators may alleviate the seizure behaviors and may down regulated the early expression of IL 6 in KA challenged seizure, but it the mechanism of the early expression of IL 6 with the homeostasis of endogenous NO mediator merits further study.nismoftheearlyexpressionofIL 6withthehome