• The Korean Journal of Physiology and Pharmacology
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• v.21 no.5
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• pp.475-485
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• 2017

The present study aimed to explore the neuroprotective effect and possible mechanisms of rhGLP-1 (7-36) against transient ischemia/reperfusion injuries induced by middle cerebral artery occlusion (MCAO) in type 2 diabetic rats. First, diabetic rats were established by a combination of a high-fat diet and low-dose streptozotocin (STZ) (30 mg/kg, intraperitoneally). Second, they were subjected to MCAO for 2 h, then treated with rhGLP-1 (7-36) (10, 20, $40{\mu}g/kg$ i.p.) at the same time of reperfusion. In the following 3 days, they were injected with rhGLP-1 (7-36) at the same dose and route for three times each day. After 72 h, hypoglycemic effects were assessed by blood glucose changes, and neuroprotective effects were evaluated by neurological deficits, infarct volume and histomorphology. Mechanisms were investigated by detecting the distribution and expression of the nuclear factor erythroid-derived factor 2 related factor 2 (Nrf2) in ischemic brain tissue, the levels of phospho-PI3 kinase (PI3K)/PI3K ratio and heme-oxygenase-1 (HO-l), as well as the activities of superoxide dismutase (SOD) and the contents of malondialdehyde (MDA). Our results showed that rhGLP-1 (7-36) significantly reduced blood glucose and infarction volume, alleviated neurological deficits, enhanced the density of surviving neurons and vascular proliferation. The nuclear positive cells ratio and expression of Nrf2, the levels of P-PI3K/PI3K ratio and HO-l increased, the activities of SOD increased and the contents of MDA decreased. The current results indicated the protective effect of rhGLP-1 (7-36) in diabetic rats following MCAO/R that may be concerned with reducing blood glucose, up-regulating expression of Nrf2/HO-1 and increasing the activities of SOD.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1161-1171
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• 2018

Objective: The aim of this study was to investigate diffusion tensor (DT) imaging-derived properties of benign oligemia, true "at risk" penumbra (TP), and the infarct core (IC) during the first 3 hours of stroke onset. Materials and Methods: The study was approved by the local animal care and use committee. DT imaging data were obtained from 14 rats after permanent middle cerebral artery occlusion (pMCAO) using a 7T magnetic resonance scanner (Bruker) in room air. Relative cerebral blood flow and apparent diffusion coefficient (ADC) maps were generated to define oligemia, TP, IC, and normal tissue (NT) every 30 minutes up to 3 hours. Relative fractional anisotropy (rFA), pure anisotropy (rq), diffusion magnitude (rL), ADC (rADC), axial diffusivity (rAD), and radial diffusivity (rRD) values were derived by comparison with the contralateral normal brain. Results: The mean volume of oligemia was $24.7{\pm}14.1mm^3$, that of TP was $81.3{\pm}62.6mm^3$, and that of IC was $123.0{\pm}85.2mm^3$ at 30 minutes after pMCAO. rFA showed an initial paradoxical 10% increase in IC and TP, and declined afterward. The rq, rL, rADC, rAD, and rRD showed an initial discrepant decrease in IC (from -24% to -36%) as compared with TP (from -7% to -13%). Significant differences (p < 0.05) in metrics, except rFA, were found between tissue subtypes in the first 2.5 hours. The rq demonstrated the best overall performance in discriminating TP from IC (accuracy = 92.6%, area under curve = 0.93) and the optimal cutoff value was -33.90%. The metric values for oligemia and NT remained similar at all time points. Conclusion: Benign oligemia is small and remains microstructurally normal under pMCAO. TP and IC show a distinct evolution of DT-derived properties within the first 3 hours of stroke onset, and are thus potentially useful in predicting the fate of ischemic brain.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.5
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• pp.275-280
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• 2008

A brief ischemic insult induces significant protection against subsequent massive ischemic events. The molecular mechanisms known as preconditioning (PC)-induced ischemic tolerance are not completely understood. We investigated whether kinetic changes of cyclooxygenase (COX)-2 during reperfusion time-periods after PC were related to ischemic tolerance. Rats were given PC by occlusion of middle cerebral artery (MCAO) for 10 min and sacrificed after the indicated time-periods of reperfusion (1, 2, 4, 8, 12, 18 or 24 h). In PC-treated rats, focal ischemia was induced by occlusion of MCA for 24 h and brain infarct volume was then studied to determine whether different reperfusion time influenced the damage. We report that the most significant protection against focal ischemia was obtained in rats with 8 h reperfusion after PC. Administration of indomethacin (10 mg/kg, oral) or rofecoxib (5 mg/kg, oral) 48 h prior to PC counteracted the effect of PC. Immunohistochemical analysis showed that COX-2 and HO-l protein were induced in PC-treated rat brain, which was significantly inhibited by rofecoxib. Taken together, we concluded that the kinetic changes of COX-2 expression during the reperfusion period after PC might be partly responsible for ischemic tolerance.

• Korean Journal of Acupuncture
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• v.22 no.3
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• pp.137-156
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• 2005

Objectives : Cnidium officinale(CO) has been used for medication for stroke in the Oriental Medicine. So this study was planned to investigate the effects of CO on the focal ischemia-induced by Middle Cerebral Artery Occlusion(MCAO) in rats Materials and methods : The focal ischemia was induced by MCAO. CO extracts through oral administration and herbal acupuncture at GB2l was carried out during 3 weeks after focal ischemia-induced. Eight-arm radial maze was used for the behavioral task. For the neuroprotective effect of CO, we investigated AchE, ChAT, and NGF-expression by immnohistochemical method. Results : The error rate in the eight-arm radial maze task was significantly decreased in normal group compared to control group on 1-6days, OA-CO1(CO oral administration, 0.8g/kg) group on 1-6days, OA-CO2(CO oral administration, 1.6g/kg) group on 1-3,5,6days, HA-CO1(CO herbal acupuncture, 0.016g/kg) group on 2,3,6days, HA-CO2(CO herbal acupuncture, 0.008g/kg) group on 1-3,5,6days. The rate of correct choice was significantly increased in OA-CO1, HA-CO2. The density of neurons in the hippocampal CA1 was the most increased in OA-CO1, HA-CO1, HA-CO2. The density of ChAT in the hippocampal CA1 was increased in OA-CO1, HA-CO2. The density of ChAT in the hippocampal CA1 was significantly increased in OA-CO1, HA-CO2. The density of NGE in the hippocampal CAI was significantly increased in OA-CO1, OA-CO2, HA-CO2. Conclusions : These results suggest that CO oral administration with 0.8g/kg and CO herbal acupuncture with 0.008g/kg might be used as a regulator of cell death of cholinergic system induced by stroke.

• The Journal of the Korea Contents Association
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• v.9 no.2
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• pp.309-317
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• 2009

This study was to investigate the effects of restoring cognition function and neurotrophic factor in the hippocampus according to memory and learning training in rats affected by brain injury. Brain injury was induced in Sprague-Dawley rats(36 rats) through middle cerebral artery occlusion(MCAo). And then experiment groups were randomly divided into three groups; Group I: Brain injury induction(n=12), Group II: the application for treadmill training after brain injury induction(n=12), Group III: the application for memory and learning training after brain injury induction(n=12). Morris water maze acquisition test and retention test were performed to test cognitive function. And the histological examination was also observed through the immunohistochemistric response of BDNF(brain-derived neurotrophic factor) in the hippocampus. For Morris water maze acquisition test, there were significant interactions among the groups with the time(p<.001). The time to find the circular platform in Group III was more shortened than in Group I, II on the 9th, 10th, 11th and 12th day. For Morris water maze retention test, there were significant differences among the groups(p<.001). The time to dwell on quadrant circular platform in Group III on the 13th day was the longest compared with other groups. And as the result of observing the immunohistochemistric response of BDNF in the hippocampus CA1, the response of immunoreactive positive in Group III on the 7th day increased more than that of Group I, II. These results suggested that the memory and learning training in rats with brain injury has a more significant impact on restoring cognitive function via the changes of neurotropic factor expression and synaptic neuroplasticity.

• Journal of Ginseng Research
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• v.47 no.2
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• pp.199-209
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• 2023

Background: Due to the interrupted blood supply in cerebral ischemic stroke (CIS), ischemic and hypoxia results in neuronal depolarization, insufficient NAD+, excessive levels of ROS, mitochondrial damages, and energy metabolism disorders, which triggers the ischemic cascades. Currently, improvement of mitochondrial functions and energy metabolism is as a vital therapeutic target and clinical strategy. Hence, it is greatly crucial to look for neuroprotective natural agents with mitochondria protection actions and explore the mediated targets for treating CIS. In the previous study, notoginseng leaf triterpenes (PNGL) from Panax notoginseng stems and leaves was demonstrated to have neuroprotective effects against cerebral ischemia/reperfusion injury. However, the potential mechanisms have been not completely elaborate. Methods: The model of middle cerebral artery occlusion and reperfusion (MCAO/R) was adopted to verify the neuroprotective effects and potential pharmacology mechanisms of PNGL in vivo. Antioxidant markers were evaluated by kit detection. Mitochondrial function was evaluated by ATP content measurement, ATPase, NAD and NADH kits. And the transmission electron microscopy (TEM) and pathological staining (H&E and Nissl) were used to detect cerebral morphological changes and mitochondrial structural damages. Western blotting, ELISA and immunofluorescence assay were utilized to explore the mitochondrial protection effects and its related mechanisms in vivo. Results: In vivo, treatment with PNGL markedly reduced excessive oxidative stress, inhibited mitochondrial injury, alleviated energy metabolism dysfunction, decreased neuronal loss and apoptosis, and thus notedly raised neuronal survival under ischemia and hypoxia. Meanwhile, PNGL significantly increased the expression of nicotinamide phosphoribosyltransferase (NAMPT) in the ischemic regions, and regulated its related downstream SIRT1/2/3-MnSOD/PGC-1α pathways. Conclusion: The study finds that the mitochondrial protective effects of PNGL are associated with the NAMPT-SIRT1/2/3-MnSOD/PGC-1α signal pathways. PNGL, as a novel candidate drug, has great application prospects for preventing and treating ischemic stroke.

• The Korean Journal of Nuclear Medicine
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• v.29 no.3
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• pp.294-306
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• 1995

There has recently been increasing interest in the use of NMDA receptor antagonists as potential neuroprotective agents for the treatment of ischemic stroke. To evaluate the neuroprotective effect of the selective non-competitive NMDA receptor antagonist MK-801 in focal cerebral ischemia, local cerebral glucose utilization (ICGU) was examined in 15 neuroanatomically discrete regions of the conscious rat brain using the 2-deoxy-D[$^{14}C$] glucose quantitative autoradiographic technique 24 hr after left middle cerebral artery occlusion (MCAO). Animals received MK-801 (5 mg/kg i.v.) or saline vehicle before (20-30 min) or after (30 min) MCAO. Both pretreatment and posttreatment of MK-801 increased occluded/non-occluded ICGU ratio in 7 and 5 of the 15 regions measured, respectively (most notably in cortical structures). Following MK-801 pretreatment, there was evidence of widespread increases in ICGU not only in the non-occluded hemisphere (12 of the 15 areas studied) but also in the occluded hemisphere (13 of the 15 areas studied), while MK-801 postreatment did not significantly increase ICGU both in the normal and occluded hemispheres. These data indicate that MK-801 has a neuroprotective effect in focal cerebral ischemia and demonstrate that MK-801 provides widespread alterations of glucose utilization in conscious animals.

• Journal of Korean Neurosurgical Society
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• v.48 no.5
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• pp.391-398
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• 2010

Objective : This study was designed to validate the cell trafficking efficiency of the in vivo bioluminescence image (BLI) study in the setting of transplantation of the luciferase expressing bone marrow-derived mesenchymal stem cells (BMSC), which were delivered at each different time after transient middle cerebral artery occlusion (MCAO) in a mouse model. Methods : Transplanting donor BMSC were prepared by primary cell culture from transgenic mouse expressing luciferase (LUC). Transient focal infarcts were induced in 4-6-week-old male nude mice. The experiment mice were divided into five groups by the time of MSC transplantation : 1) sham-operation group, 2) 2-h group, 3) 1-day group, 4) 3-day group, and 5) 1-week group. BLI for detection of spatial distribution of transplanted MSC was performed by detecting emitted photons. Migration of the transplanted cells to the infarcted area was confirmed by histological examinations. Differences between groups were evaluated by paired t-test. Results : A focal spot of bioluminescence was observed at the injection site on the next day after transplantation by Signal intensity of bioluminescence. After 4 weeks, the mean signal intensities of 2-h, 1-day, 3-day, and 1-week group were $2.6{\times}10^7{\pm}7.4{\times}10^6$. $6.1{\times}10^6{\pm}1.2{\times}10^6$, $1.7{\times}10^6{\pm}4.4{\times}10^5$, and $8.9{\times}10^6{\pm}9.5{\times}10^5$, respectively. The 2-h group showed significantly higher signal intensity (p<0.01). The engrafted BMSC showed around the infarct border zones on immunohistochemical examination. The counts of LUC-positive cells revealed the highest number in the 2-h group, in agreement with the results of BLI experiments (p<0.01). Conclusion : In this study, the results suggested that the transplanted BMSC migrated to the infarct border zone in BLI study and the higher signal intensity of LUC-positive cells seen in 2 hrs after MSC transplantation in MCAO mouse model. In addition, noninvasive imaging in real time is an ideal method for tracking stem cell transplantation. This method can be widely applied to various research fields of cell transplantation therapy.

• Journal of Korean Neurosurgical Society
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• v.58 no.3
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• pp.167-174
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• 2015

Objective : This study investigates the role of a burr hole and calvarial bone marrow-derived stem cells (BMSCs) in a transient ischemic brain injury model in the rat and postulates a possible mechanism for the efficacy of multiple cranial burr hole (MCBH) surgery in moyamoya disease (MMD). Methods : Twenty Sprague-Dawley rats (250 g, male) were divided into four groups : normal control group (n=5), burr hole group (n=5), ischemia group (n=5), and ischemia+burr hole group (n=5). Focal ischemia was induced by the transient middle cerebral artery occlusion (MCAO). At one week after the ischemic injury, a 2 mm-sized cranial burr hole with small cortical incision was made on the ipsilateral (left) parietal area. Bromodeoxyuridine (BrdU, 50 mg/kg) was injected intraperitoneally, 2 times a day for 6 days after the burr hole trephination. At one week after the burr hole trephination, brains were harvested. Immunohistochemical stainings for BrdU, CD34, VEGF, and Doublecortin and Nestin were done. Results : In the ischemia+burr hole group, BrdU (+), CD34 (+), and Doublecortin (+) cells were found in the cortical incision site below the burr hole. A number of cells with Nestin (+) or VEGF (+) were found in the cerebral parenchyma around the cortical incision site. In the other groups, BrdU (+), CD34 (+), Doublecortin (+), and Nestin (+) cells were not detected in the corresponding area. These findings suggest that BrdU (+) and CD34 (+) cells are bone marrow-derived stem cells, which may be derived from the calvarial bone marrow through the burr hole. The existence of CD34 (+) and VEGF (+) cells indicates increased angiogenesis, while the existence of Doublecortin (+), Nestin (+) cells indicates increased neurogenesis. Conclusion : Based on these findings, the BMSCs through burr holes seem to play an important role for the therapeutic effect of the MCBH surgery in MMD.