• Journal of Korean Academy of Nursing
• /
• v.49 no.3
• /
• pp.317-328
• /
• 2019

Purpose: The purpose of this study was to identify the effect of ghrelin on memory impairment in a rat model of vascular dementia induced by chronic cerebral hypoperfusion. Methods: Randomized controlled groups and the posttest design were used. We established the representative animal model of vascular dementia caused by bilateral common carotid artery occlusion and administered $80{\mu}g/kg$ ghrelin intraperitoneally for 4 weeks. First, behavioral studies were performed to evaluate spatial memory. Second, we used molecular biology techniques to determine whether ghrelin ameliorates the damage to the structure and function of the white matter and hippocampus, which are crucial to learning and memory. Results: Ghrelin improved the spatial memory impairment in the Y-maze and Morris water maze test. In the white matter, demyelination and atrophy of the corpus callosum were significantly decreased in the ghrelin-treated group. In the hippocampus, ghrelin increased the length of hippocampal microvessels and reduced the microvessels pathology. Further, we confirmed angiogenesis enhancement through the fact that ghrelin treatment increased vascular endothelial growth factor (VEGF)-related protein levels, which are the most powerful mediators of angiogenesis in the hippocampus. Conclusion: We found that ghrelin affected the damaged myelin sheaths and microvessels by increasing angiogenesis, which then led to neuroprotection and improved memory function. We suggest that further studies continue to accumulate evidence of the effect of ghrelin. Further, we believe that the development of therapeutic interventions that increase ghrelin may contribute to memory improvement in patients with vascular dementia.

• Journal of Ginseng Research
• /
• v.47 no.6
• /
• pp.735-742
• /
• 2023

Background: Gintonin is a new material of ginseng that acts through the ginseng-derived lysophosphatidic acid (LPA) receptor ligand. The gintonin-enriched fraction (GEF) inhibits amyloid plaque accumulation in the cortex and hippocampus, improves cognitive dysfunction by increasing acetylcholine levels, and promoted hippocampal neurogenesis in an animal model of Alzheimer's disease. We evaluated the effect of the GEF on the cognitive performance of subjects with subjective memory impairment (SMI). Methods: In this eight-week, randomized, assessor- and participant-blinded, placebo-controlled study, participants with SMI were assigned to three groups receiving placebo, GEF 300 mg/day or GEF 600 mg/day. The Korean versions of the Alzheimer's Disease Assessment Scale (K-ADAS), Mini-Mental State Examination (K-MMSE), and Stroop color-word test (K-SCWT) were also evaluated along with the safety profiles. Results: One hundred thirty-six participants completed the study. After eight weeks, we analyzed intergroup differences in primary or secondary outcome score changes. When we compared the GEF group with the placebo group, we observed significant improvements in the K-ADAS and K-SCWT scores. The GEF group did not show a significant improvement in K-MMSE and BDI scores compared to the placebo group. No adverse events were observed in the gintonin and placebo groups for eight weeks. Conclusion: The GEF is safe and effective in improving subjective cognitive impairment related to both the K-ADAS and K-SCWT in this study. However, further large-scale and randomized controlled studies are warranted to secure other cognitive function tests besides the K-ADAS and K-SCWT, and to confirm the findings of the current study.

• Journal of Life Science
• /
• v.30 no.6
• /
• pp.513-521
• /
• 2020

B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi1) is a polycomb group protein and a core component of polycomb repressive complex 1. Initial research into Bmi1 has focused on its role in tumorigenesis, and it is generally accepted that it is important for the proliferation and survival of cancer cells. However, more recent studies have revealed that Bmi1 is downregulated in brains with neurodegenerative disease and that it regulates the function of mitochondria and reactive oxygen species levels. In this study, we tested the therapeutic potential of Bmi1 in pilocarpine-induced seizures in Bmi1-knockout mice. Bmi1 expression transiently increased in the hippocampal CA1 and CA3 and the dentate gyrus following pilocarpine-induced status epilepticus (SE). In terms of seizure behavior, SE induction was 43.14% and 53.57% for Bmi1^+/+ and Bmi1^+/- mice, respectively. However, there was no significant difference in mortality or hippocampal damage between the two groups. Two months after SE induction, the frequency of epileptic seizures in the Bmi1^+/- mice was 50% lower than in the control group, although the difference was not statistically significant. In addition, mossy fiber outgrowth in the Bmi1^+/- mice was significantly higher than in their wild-type littermates. Taken together, these data indicate that reduced Bmi1 activity increases pilocarpine-induced seizure probability and mossy fiber outgrowth.

• Journal of Korean Medicine Rehabilitation
• /
• v.21 no.2
• /
• pp.1-13
• /
• 2011

Objectives : We investigated the effect of Haein-tang(Hairen-tang) on short-term memory and apoptosis in dentate gyrus of the gerbils with transient global ischemia. Methods : For the induction of cerebral ischemia model in mice, common carotid arteries of gerbils were occluded with aneurysm clips for 5 min. One day after operation, Haein-tang(Hairen-tang) was administrated orally injected once a day for 15 consecutive days. Gerbils were randomly divided into four group(n=10 in each group): sham-operation group, ischemia-induction group, ischemia-induction and 50 mg/kg Haein-tang(Hairen-tang)-treated group, ischemia-induction and 100 mg/kg Haein-tang(Hairen-tang)-treated group, and ischemia-induction and 200 mg/kg Haein-tang(Hairen-tang)-treated group. The effect of Haein-tang(Hairen-tang) on memory function was investigated by using step-down avoidance task. Apoptosis was confirmed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) staining and immunohistochemistry for caspase-3. Western blot analysis for the expressions of Bax and Bcl-2 protein was also conducted. Results : 1. Haein-tang extract significantly enhanced short-term memory in step-down avoidance task and 100 mg/kg, 200 mg/kg Haein-tang-treated group. 2. Haein-tang extract significantly suppressed TUNEL-positive cells after transient global ischemia and 50 mg/kg, 100 mg/kg, 200 mg/kg Haein-tang-treated group. 3. Haein-tang extract significantly increased caspase-3 positive cells in the hippocampal dentate gyrus after transient global ischemia and 50 mg/kg, 100 mg/kg, 200 mg/kg Haein-tang-treated group. 4. Haein-tang extract significantly decreased Bax protein expressions in the hippocampus after transient global ischemia and 100 mg/kg, 200 mg/kg, Haein-tang-treated group. Haein-tang extract significantly increased Bcl-2 protein expressions in the hippocampal dentate gyrus after transient global ischemia and 50 mg/kg, 100 mg/kg, 200 mg/kg, Haein-tang-treated group. Haein-tang extract significantly decreased Ratio of Bax protein to Bcl-2 protein in the hippocampus after transient global ischemia and 100 mg/kg, 200 mg/kg Haein-tang-treated group. Conclusions : While Haein-tang(Hairen-tang) treatment improved short-term memory by suppressing on ischemia-induction apoptosis. In the present study, Haein-tang(Hairen-tang) shows protective effect on transient global ischemia.

• Journal of Life Science
• /
• v.30 no.11
• /
• pp.939-946
• /
• 2020

Stroke is one of the leading causes of neurological disability worldwide and stroke patients exhibit a range of motor, cognitive, and psychiatric impairments. GPR88 is an orphan G protein-coupled receptor (GPCR) that is highly expressed in striatal medium spiny neurons; its deletion results in poor motor coordination and motor learning. There are currently no studies on the involvement of GPR88 in stroke or in post-stroke brain function recovery. In this study, we found a decrease in GPR88 protein and mRNA expression levels in an ischemic mouse model using Western blot and real-time PCR, respectively. In addition, we observed that, among the three types of cells derived from the brain (brain microvascular endothelial cells, BV2 microglial cells, and HT22 hippocampal neuronal cells), the expression of GPR88 was highest in HT22 neuronal cells, and that GPR88 expression was downregulated in HT22 cells under oxygen-glucose deprivation (OGD) conditions. Moreover, pretreatment with RTI- 13951-33 (10 mg/kg), a brain-penetrant GPR88 agonist, ameliorated brain injury following ischemia, as evidenced by improvements in infarct volume, vestibular-motor function, and neurological score. Collectively, our results suggest that GPR88 could be a potential drug target for the treatment of central nervous system (CNS) diseases, including ischemic stroke.

• Journal of Life Science
• /
• v.17 no.11
• /
• pp.1464-1471
• /
• 2007

Diabetes mellitus is a chronic metabolic disorder, leading to many complications including cognitive deficit. Regular exercise has often been recommended as a therapeutic maneuver to the diabetic patients for the prevention of secondary complications. In the present study, the effects of treadmill exercise on memory and brain-derived neurotrophic factor (BDNF) in the hippocampus of streptozotocin (STZ)-induced diabetic rats were investigated. Male SD rats, aged 6 weeks, were randomly assigned to the following three groups: control group(n=8), STZ-induced diabetic group(n=8), and STZ-induced diabetes and exercise group(n=8). Diabetes was induced by a single injection of STZ (50 mg/kg body weight). Treadmill running was conducted with duration and frequency of 30 minutes and 5 times per week, respectively, for 8 weeks. Memories were tested in the Morris water maze. Western blotting was performed to detect BDNF expression in the hippocampus. In this study, we found that compared to the control group, the STZ-induced diabetes group had a significantly impaired cognitive performance along with suppressed BDNF expression in the hippocampus and the exercise group had a higher cognitive function in diabetic rats. Therefore, the current findings of the study show that a treadmill running exercise can improve diabetes-induced impairment of cognitive function. And the improved cognitive function appears to be related to an alleviation in diabetes-induced BDNF expression in hippocampus.

• Animal cells and systems
• /
• v.15 no.4
• /
• pp.279-286
• /
• 2011

Hypoxic ischemia injury is a common cause of functional brain damage, resulting from a decrease in cerebral blood flow and oxygen supply to the brain. The main problems associated with hypoxic ischemia to the brain are memory impairment and dopamine dysfunction. Hypothermia has been suggested to ameliorate the neurological impairment induced by various brain insults. In this study, we investigated the effects of hypothermia on memory function and dopamine synthesis following hypoxic ischemia to the brain in rats. For this purpose, a step-down avoidance task, a radial eight-arm maze task, and immunohistochemistry for tyrosine hydroxylase (TH) and 5-bromo-2'-deoxyuridine (BrdU) were performed. The present results indicated that the hypoxic ischemia-induced disturbance of the animal's performances and spatial working memory was associated with a decrement in TH expression in the substantia nigra and striatum, and an increase in cell proliferation in the hippocampal dentate gyrus. Hypothermia treatment improved the animals' performance and spatial working memory by suppressing the decrement in TH expression in the substantia nigra and striatum and the increase in cell proliferation in the dentate gyrus. We suggest that hypothermia can be an efficient therapeutic modality to facilitate recovery following hypoxic ischemia injury to the brain, presumably by modulating the dopaminergic cell loss.

• Journal of Korean Biological Nursing Science
• /
• v.18 no.1
• /
• pp.36-42
• /
• 2016

Purpose: Stress activates the sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA) axis and induces the release of glucocorticoids. Saccharin is 300 times sweeter than sucrose, but does not increase blood insulin levels. Thus, this study was designed to evaluate the effect of saccharin intake in restraint-induced stress response reduction in rats. Methods: Adult male Sprague-Dawley (SD) rats had stress induced by restraint for 2 hours/day for 1 week. Saccharin was provided in sufficient amounts to allow them to intake it voluntarily at 0.1% diluted in water. The Y-maze test and forced swim test (FST) were performed to evaluate cognitive function and the depressive behavior of the rats. The protein expression of the glucocorticoid receptor (GR) in hippocampal cornu ammonis (CA) 1 was investigated by using immunohistochemistry. Results: It was found that, the percentage of alternation in the Y-maze test was significantly (p<.01) higher in the Stress + saccharin group than in the Stress group. Immobility time in the FST was significantly (p<.01) lower in the Stress + saccharin group than in the Stress group. Also, the positive cells of GR in hippocampus CA1 were significantly (p<.05) lower in the Stress + saccharin group than in the Stress group. Conclusion: This study showed that there was an effect of saccharin intake in restraint-induced stress response reduction in rats.

• Biomedical Science Letters
• /
• v.21 no.2
• /
• pp.92-102
• /
• 2015

This work aimed to study whether rice bran extract fermented with Lactobacillus plantarum (LW) promotes functional recovery and reduces cognitive impairment after ischemic brain injury. Ischemic brain injury was induced by middle cerebral artery occlusion (MCAO) in rats. Four groups were studied, namely the (1) sham, (2) vehicle, (3) donepezil, and (4) LW groups. Animals were injected with LW once a day for 7 days after middle cerebral artery occlusion. LW group showed significantly improved neurological function as compared to the vehicle group, as well as enhanced learning and memory in the Morris water maze. The LW group showed the greatest functional recovery. Moreover, the LW group showed an enhanced more survival cells anti-apoptotic effect in the cortex and neural cell densities in the hippocampal DG and CA1. In addition, this group showed enhanced expression of neurotrophic factors, antioxidant genes, and the acetylcholine receptor gene, as well as synaptophysin (SYP), Fox-3 (NeuN), doublecortin (DCX), and choline acetyltransferase (ChAT) proteins. Our findings indicate that LW treatment showed the largest effects in functional recovery and cognitive improvement after ischemic brain injury through stimulation of the acetylcholine receptor, antioxidant genes, neurotrophic factors, and expression of NeuN, SYP, DCX, and ChAT.

• BMB Reports
• /
• v.43 no.10
• /
• pp.677-682
• /
• 2010

Kv4.2, a pore-forming $\alpha$-subunit of voltage-gated A-type potassium channels, is expressed abundantly in the soma and dendrites of hippocampal neurons, and is responsible for somatodendritic $I_A$ current. Recent studies have suggested that changes in the surface levels of Kv4.2 potassium channels might be relevant to synaptic plasticity. Although the function and expression of Kv4.2 protein have been extensively studied, the dendritic localization of Kv4.2 mRNA is not well described. In this study, Kv4.2 mRNAs were shown to be localized in the dendrites near postsynaptic regions. The dendritic transport of Kv4.2 mRNAs were mediated by microtubule-based movement. The 500 nucleotides of specific regions within the 3'-untranslated region of Kv4.2 mRNA were found to be necessary and sufficient for its dendritic localization. Collectively, these results suggest that the dendritic localization of Kv4.2 mRNAs might regulate the dendritic surface level of Kv4.2 channels and synaptic plasticity.