• Journal of Korean Neurosurgical Society
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• v.41 no.1
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• pp.30-38
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• 2007

Objective : To elucidate the role of aquaporin-4[AQP4] in cerebral edema formation, we studied the expression and subcellular localization of AQP4 in astrocytes after focal cerebral ischemia. Methods : Cerebral ischemia were induced by permanent middle cerebral artery[MCA] occlusion in rats and estimated by the discoloration after triphenyltetrazolium chloride[TTC] immersion. Change of AQP4 expression were evaluated using western blot. Localization of AQP4 was assessed by confocal microscopy and its interaction with ${\alpha}-syntrophin$ was analyzed by immunoprecipitation. Results : After right MCA occlusion, the size of infarct and number of apoptotic cells increased with time. The ratio of GluR1/GluR2 expression also increased during ischemia. The polarized localization of AQP4 in the endfeet of astrocytes contacting with ventricles, vessels and pia mater was changed into the diffuse distribution in cytoplasm. The interactions of AQP4 and Kir with ${\alpha}-syntrophin$, an adaptor of dystrophin complex, were disrupted by cerebral ischemia. Conclusion : The deranged spatial buffering function of astrocytes due to mislocalized AQP4/Kir4.1 channel as well as increased assembly of $Ca^{2+}$ permeable AMPA receptors might contribute to the development of edema formation and the excitotoxic neuronal cell death during ischemia.

• Proceedings of the Korean Society of Life Science Conference
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• 2001.09a
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• pp.120-120
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• 2001

• The Journal of Korean Medicine
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• v.28 no.2 s.70
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• pp.213-223
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• 2007

Objective : Alzheimer's disease (AD) is a geriatric dementia that is widespread in old age. With an aging populace, AD is a looming problem in public health service. Alzheimer's disease is characterized by specific neuronal degeneration in certain areas of the brain. Mutations and abnormal expression of several genes are associated with ${\beta}-amyloid$ deposits and Alzheimer's disease; among them APP, PS1, and PS2, SOD, free radical, ROS. Methods:We studied herbal medicines that have a relationship to brain degeneration. From pre-modern times, although a variety of oriental prescriptions of Aster tataricus have been traditionally utilized for the treatment of AD, their pharmacological effects and action mechanisms have not yet been fully elucidated. Result : Based on morphological observations by phase-contrast microscope, TUNEL assay and MTT in the culture media, $H_20_2-induced$ cell death was significantly inhibited by Aticus. We examined by ROS formation, catalase activity and GSH activity. We studied the protective effect and inhibitory effects of neurotoxicity in $H_20_2-induced$ PC-12 cells by Aticus. Findings from our experiments show that Aticus inhibits apoptosis, which has neurotoxicities and cell damage in PC-12 cells. In addition, treatment with Aticus ($>25{\mu}g/ml$ for 6hrs) partially prevented $H_20_2-induced$ cytotoxicity in PC-12 cells, and induced a protective effect. Conclusion : As the result of this study, in the Aticus group, the apoptosis in the nervous system was inhibited, protected against the degeneration of PC-12 cells by $H_20_2$. Taken together, Aticus exhibited inhibition of $H_20_2-induced$ apoptotic cell death. Aticus was found to induce protective effect on GSH and catalase in PC-12 cells. Based on these findings, Aticus may be beneficial for the treatment of AD.

• Korean Journal of Medicinal Crop Science
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• v.14 no.2
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• pp.70-76
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• 2006

Paeoniae radix has been widely used for its anti-allergic, anti-inflammatory and analgesic effects, and demonstrated to have anticonvulsant, memory enhancing and anxiolytic activities. The present study was performed to examine the protective effect of methanol extract of Paeoniae radix (PR) from Paeoniae Japonica Miyabe et Takeda (Paeoniaceae) on hydrogen peroxide $(H_2O_2)-induced$ neurotoxicity using cultured rat cerebral cortical neuron. $H_2O_2$ produced a concentration-dependent reduction of neuronal viability, PR, over a concentration range of 10 to $100\;{\mu}g/ml$ showed concentration-dependent decrease of the $H_2O_2$$(100\;{\mu}M)-induced$ neuronal cell death, as assessed by a 3-[4,5-dimethylthiazol-2-yl]-2,5-di-phenyl-tetrazolium bromide assay and the number of apoptotic nuclei, evidenced by Hoechst 33342 staining. PR $(100\;{\mu}g/ml$ inhibited $100\;{\mu}M$ $H_2O_2-induced$ elevation of the cytosolic $Ca^{2+}$ concentration $([Ca^{2+}]_c)$, which was measured by a fluorescent dye, flue-4 AM. PR $(50\;{\mu}g/ml$ inhibited glutamate release into medium induced by $100\;{\mu}M$ $H_2O_2$, which was measured by HPLC, and generation of reactive oxygen species (ROS). These results suggest that PR may mitigate the $H_2O_2-induced$ neurotoxiciy by interfering with the increase of $[Ca^{2+}]_c$, and then inhibiting glutamate release and generation of ROS in cultured neurons.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.217-225
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• 2021

This study aimed to investigate the neuroprotective effects of 1-methoxylespeflorin G11 (MLG), a pterocarpan, against glutamate-induced neurotoxicity in neuronal HT22 hippocampal cells. The protective effects of MLG were evaluated using MTT assay and microscopic analysis. The extent of apoptosis was studied using flow cytometric analysis performed on the damaged cells probed with annexin V/propidium iodide. Moreover, mitochondrial reactive oxygen species (ROS) were assessed using flow cytometry through MitoSOXTM Red staining. To determine mitochondrial membrane potential, staining with tetramethylrhodamine and JC-1 was performed followed by flow cytometry. The results demonstrated that MLG attenuates glutamate-induced apoptosis in HT22 cells by inhibiting intracellular ROS generation and mitochondrial dysfunction. Additionally, MLG prevented glutamate-induced apoptotic pathway in HT22 cells through upregulation of Bcl-2 and downregulation of cleaved PARP-1, AIF, and phosphorylated MAPK cascades. In addition, MLG treatment induced HO-1 expression in HT22 cells. These results suggested that MLG exhibits neuroprotective effects against glutamate-induced neurotoxicity in neuronal HT22 cells by inhibiting oxidative stress and apoptosis.

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.18-23
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• 2011

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuronal loss and extracellular senile plaques containing $\beta$-amyloid peptide (A$\beta$). The deposition of the A$\beta$ peptide following proteolytic processing of amyloid precursor protein (APP) by $\beta$-secretase (BACE1) and $\gamma$-secretase is a critical feature in the progression of AD. Among the plant extracts tested, the ethanol extract of Petasites japonicus leaves showed novel protective effect on B103 neuroblastoma cells against neurotoxicity induced by A$\beta$, as well as a strong suppressive effect on BACE1 activity. Ethanol extracts of P. japonicus leaves were sequentially extracted with methylene chloride, ethyl acetate and butanol and evaluated for potential to inhibit BACE1, as well as to suppress A$\beta$-induced neurotoxicity. Exposure to A$\beta$ significantly reduced cell viability and increased apoptotic cell death. However, pretreatment with ethyl acetate fraction of P. japonicus leaves prior to A$\beta$ (50 ${\mu}M$) significantly increased cell viability (p<0.01). In parallel, cell apoptosis triggered by A$\beta$ was also dramatically inhibited by ethyl acetate fraction of P. japonicus leaves. Moreover, the ethyl acetate fraction suppressed caspase-3 activity to the basal level at 30 ppm. Taken together, these results demonstrated that P. japonicus leaves appear to be a useful source for the inhibition and/or prevention of AD by suppression of BACE1 activity and attenuation of A$\beta$ induced neurocytotoxicity.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.5
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• pp.263-271
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• 2006

Since astrocytes were shown to play a central role in maintaining neuronal viability both under normal conditions and during stress such as ischemia, studies of the astrocytic response to stress are essential to understand many types of brain pathology. The micro array system permitted screening of large numbers of genes in biological or pathological processes. Therefore, the gene expression patterns in the in vitro model of astrocytes following exposure to oxygen-glucose deprivation (OGD) were evaluated by using the micro array analysis. Primary astrocytic cultures were prepared from postnatal Swiss Webster mice. The cells were exposed to OGD for 4 hrs at $37^{\circ}C$ prior to cell harvesting. From the cultured cells, we isolated mRNA, synthesized cDNA, converted to biotinylated cRNA and then reacted with GeneChips. The data were normalized and analyzed using dChip and GenMAPP tools. After 4 hrs exposure to OGD, 4 genes were increased more than 2 folds and 51 genes were decreased more than 2 folds compared with the control condition. The data suggest that the OGD has general suppressive effect on the gene expression with the exception of some genes which are related with ischemic cell death directly or indirectly. These genes are mainly involved in apoptotic and protein translation pathways and gap junction component. These results suggest that microarray analysis of gene expression may be useful for screening novel molecular mediators of astrocyte response to ischemic injury and making profound understanding of the cellular mechanisms as a whole. Such a screening technique should provide insights into the molecular basis of brain disorders and help to identify potential targets for therapy.

• Nutrition Research and Practice
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• v.17 no.5
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• pp.899-916
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• 2023

BACKGROUND/OBJECTIVES: Oxidative stress is a fundamental neurodegenerative disease trigger that damages and decimates nerve cells. Neurodegenerative diseases are chronic central nervous system disorders that progress and result from neuronal degradation and loss. Recent studies have extensively focused on neurodegenerative disease treatment and prevention using dietary compounds. Heseperetin is an aglycone hesperidin form with various physiological activities, such as anti-inflammation, antioxidant, and antitumor. However, few studies have considered hesperetin's neuroprotective effects and mechanisms; thus, our study investigated this in hydrogen peroxide (H₂O₂)-treated SH-SY5Y cells. MATERIALS/METHODS: SH-SY5Y cells were treated with H₂O₂ (400 µM) in hesperetin absence or presence (10-40 µM) for 24 h. Three-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assays detected cell viability, and 4',6-diamidino-2-phenylindole staining allowed us to observe nuclear morphology changes such as chromatin condensation and apoptotic nuclei. Reactive oxygen species (ROS) detection assays measured intracellular ROS production; Griess reaction assays assessed nitric oxide (NO) production. Western blotting and quantitative polymerase chain reactions quantified corresponding mRNA and proteins. RESULTS: Subsequent experiments utilized various non-toxic hesperetin concentrations, establishing that hesperetin notably decreased intracellular ROS and NO production in H₂O₂-treated SH-SY5Y cells (P < 0.05). Furthermore, hesperetin inhibited H₂O₂-induced inflammation-related gene expression, including interluekin-6, tumor necrosis factor-α, and nuclear factor kappa B (NF-κB) p65 activation. In addition, hesperetin inhibited NF-κB translocation into H₂O₂-treated SH-SY5Y cell nuclei and suppressed mitogen-activated protein kinase protein expression, an essential apoptotic cell death regulator. Various apoptosis hallmarks, including shrinkage and nuclear condensation in H₂O₂-treated cells, were suppressed dose-dependently. Additionally, hesperetin treatment down-regulated Bax/Bcl-2 expression ratios and activated AMP-activated protein kinase-mammalian target of rapamycin autophagy pathways. CONCLUSION: These results substantiate that hesperetin activates autophagy and inhibits apoptosis and inflammation. Hesperetin is a potentially potent dietary agent that reduces neurodegenerative disease onset, progression, and prevention.

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.215-220
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• 2005

Objective : Many researchers believe that the hypothermia shows neuro-protective effect on brain injury. To understand the molecular mechanism of the hypothermic treatment, this study investigated its effects on the expression of cell death or survival related proteins such as p53, Bcl-2 and Bax in the rat traumatic brain injury[TBI] model. Methods : Twenty rats [Spraque Dawley, $200{\sim}250g$] were subjected to the brain injury of moderate severity [$2.4{\sim}2.6atm$] using the fluid percussion injury device and five rats were received only same surgery as controls. During 30minutes after the brain injury, the hypothermia group was maintained the body temperature around $34^{\circ}C$ while the control group were maintained that of $36^{\circ}C$. Five rats in each group were sacrificed 12h or 24h after brain injury and their brain sections was analyzed for physical damages by H-E stains and the extent of apoptosis by TUNEL assay and immunohistochemical stains. The tissue damage after TBI was mainly observed in the ipsilateral cortex and partly in the hippocampus. Results : Apoptosis was observed by TUNEL assay and the Bax protein was detected in both sample which harvested 12h and 24h after TBI. In the hypothermia treatment group, tissue damage and apoptosis were reduced in HE stains and TUNEL assay. In hypothermia treatment group rat shows more expression of the Bcl-2 protein and shows less expression of the Bax protein, at both 12h and 24h after TBI. Conclusion : These results show that the hypothermia treatment is an effective treatment after TBI, by reducing the apoptotic process. Therefore, it could be suggested that hypothermia has a high therapeutic value for treating tissue damages after TBI.

• The Korea Journal of Herbology
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• v.20 no.3
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• pp.29-41
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• 2005

Objectives : The use of natural products with therapeutic properties is as ancient as human civilisation and, for a long time, mineral, plant and animal products were the main sources of drugs. Catalposide, the major iridoid glycoside isolated from the stem bark of Catalpa ovata G. Don (Bignoniceae) has been shown to possess anti-microbial and anti-tumoral properties. Heme oxygenase-1 (HO-1) is a stress response protein and is known to play a protective role against the oxidative injury. In this study, we examined whether catalposide could protect Neuro 2A cells, a kind of neuronal cell lines, from oxidative damage through the induction of HO-1 protein expression and HO activity. We also examined the effects of catalposide on the productions of tumor necrosis $factor-{\alpha}\;(TNF-{\alpha})$ and nitric oxide (NO) on RAW 264.7 macrophages activated with the endotoxin lipopolysaccharide. Methods : HO-1 expression in Neuro 2A cells was measured by Western blotting analysis. NO and $TNF--{\alpha}$ produced by RAW 264.7 macrophage were measured by Griess reagent and enzyme-linked immunosorbent assay, respectively. Results : The treatment of the cells with catalposide resulted in dose- and time-dependent up-regulations of both HO-1 protein expression and HO activity. Catalposide protected the cells from hydrogen peroxide-induced cell death. The protective effect of catalposide on hydrogen peroxide-induced cell death was abrogated by zinc protoporphyrin IX, a HO inhibitor. Additional experiments revealed the involvement of CO in the cytoprotective effect of catalposide-induced HO-1. In addition, catalposide inhibited the productions of $TNF--{\alpha}$ and NO with significant decreases in mRNA levels of $TNF--{\alpha}$ and inducible NO synthase. Conclusions : Our results indicate that catalposide is a potent inducer of HO-1 and HO-1 induction is responsible for the catalposide-mediated cytoprotection against oxidative damage and that catalposide may have therapeutic potential in the control of inflammatory disorders.