scholarly journals Fucosterol from an Edible Brown Alga Ecklonia stolonifera Prevents Soluble Amyloid Beta-Induced Cognitive Dysfunction in Aging Rats

Marine Drugs ◽  
2018 ◽  
Vol 16 (10) ◽  
pp. 368 ◽  
Author(s):  
Jeong Oh ◽  
Jae Choi ◽  
Taek-Jeong Nam
Keyword(s):  
Cognitive Impairment ◽  
Er Stress ◽  
Cognitive Dysfunction ◽  
Amyloid Beta ◽  
Hippocampal Neurons ◽  
Biological Activities ◽  
Brown Seaweed ◽  
Ecklonia Stolonifera ◽  
Neuroprotective Effects ◽  
Aging Rats

Fucosterol from edible brown seaweeds has various biological activities, including anti-inflammatory, anti-adipogenic, antiphotoaging, anti-acetylcholinesterase, and anti-beta-secretase 1 activities. However, little is known about its effects on soluble amyloid beta peptide (sAβ)-induced endoplasmic reticulum (ER) stress and cognitive impairment. Fucosterol was isolated from the edible brown seaweed Ecklonia stolonifera, and its neuroprotective effects were analyzed in primary hippocampal neurons and in aging rats. Fucosterol attenuated sAβ1-42-induced decrease in the viability of hippocampal neurons and downregulated sAβ1-42-induced increase in glucose-regulated protein 78 (GRP78) expression in hippocampal neurons via activation of tyrosine receptor kinase B-mediated ERK1/2 signaling. Fucosterol co-infusion attenuated sAβ1-42-induced cognitive impairment in aging rats via downregulation of GRP78 expression and upregulation of mature brain-derived neurotrophic factor expression in the dentate gyrus. Fucosterol might be beneficial for the management of cognitive dysfunction via suppression of aging-induced ER stress.

scholarly journals Roscovitine, a CDK5 Inhibitor, Alleviates Sevoflurane-Induced Cognitive Dysfunction via Regulation Tau/GSK3β and ERK/PPARγ/CREB Signaling

2017 ◽  
Vol 44 (2) ◽  
pp. 423-435 ◽  
Author(s):  
Jianhui Liu ◽  
Junjun Yang ◽  
Yinhua Xu ◽  
Gang Guo ◽  
Li Cai ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Dysfunction ◽  
Hippocampal Neurons ◽  
Glycogen Synthase ◽  
Neuronal Damage ◽  
Immunohistochemical Analysis ◽  
Peroxisome Proliferator ◽  
Neuroprotective Effects ◽  
Peroxisome Proliferator Activated Receptor ◽  
Ppar Γ

Background/Aims: Multiple exposures to anesthesia in children may increase the risk of developing cognitive impairment. Sevoflurane is an anesthetic that is commonly used in children during surgery. Cyclin-dependent kinase (CDK) 5 is involved in the regulation of sevoflurane-induced cognitive dysfunction, but the mechanistic details remain unclear. The present study evaluated the mechanism by which CDK5 mediates sevoflurane-induced cognitive dysfunction in mice. Methods: Hippocampal neurons were isolated from postnatal day 0 C57BL/6 mouse pups. Six-day-old wild-type mice were exposed to sevoflurane and then treated with the CDK5 inhibitor roscovitine. The effects on cognitive function were evaluated with the Morris water maze and neuronal damage in the hippocampus was assessed by immunohistochemical analysis. Results: CDK5 activation increased neuronal damage by inducing Tau/glycogen synthase kinase (GSK) 3β and suppressing extracellular signal-regulated kinase (ERK)/peroxisome proliferator-activated receptor (PPAR)γ/cyclic AMP response element-binding protein (CREB) signaling following exposure to sevoflurane. CDK5 inhibition by roscovitine administration alleviated sevoflurane-induced neuronal damage and cognitive impairment. Conclusions: Inhibiting CDK5 with roscovitine has neuroprotective effects against neuronal injury and cognitive dysfunction caused by sevoflurane anesthesia that are exerted via modulation of Tau/GSK3β and ERK/PPARγ/CREB signaling.

scholarly journals Combination of isoflurane and propofol, a means for general anesthesia in the orthopedic surgery of perioperative cerebral hypoperfusion rats to avoid cognitive impairment Anesthesia of perioperative cerebral hypoperfusion

2020 ◽  
Author(s):  
Xinyue Bu ◽  
Tang Li ◽  
Haiyun Wang ◽  
Zhengyuan Xia ◽  
Di Guo ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Function ◽  
Er Stress ◽  
General Anesthesia ◽  
Underlying Mechanism ◽  
Cerebral Hypoperfusion ◽  
Nissl Staining ◽  
Aging Rats ◽  
Biochemical Analyses ◽  
Common Carotid Arteries

Abstract Background: Perioperative cerebral hypoperfusion often occurs. However, the underlying mechanism of cognitive impairment resulting when perioperative cerebral hypoperfusion occurs remain mostly to be determined. Anesthetic isoflurane induces neuronal injury via endoplasmic reticulum (ER) stress, whereas sub-anesthetic dose of propofol improves postoperative cognitive function. However, the effects of the combination of isoflurane plus propofol, which is a common combination of anesthesia for patient, on ER stress and the associated cognitive function remain unknown. Methods: We therefore set out to determine the effects of isoflurane plus propofol on the ER stress and cognitive function in the rats insulted by cerebral hypoperfusion. A ligation of bilateral common carotid arteries (CCA) surgery was adopted to prepare rats as cerebral hypoperfusion (CH) animal model. A second surgery, open reduction and internal fixation (ORIF), requiring general anesthesia, was operated 30 days later so that the effects of anesthetics on cognitive function of these CH rats could be assessed. The rats received isoflurane alone (1.9%), propofol alone (40 mg·kg -1 ·h -1 ) or a combination of isoflurane and propofol (1% and 20 mg·kg -1 ·h -1 or 1.4% and 10 mg·kg -1 ·h -1 ). Behavior studies (Fear Conditioning test), histological analyses (Nissl staining) and biochemical analyses (western blotting for the harvested rat brain tissues) were employed in the studies. Results: We found that the combination of 1% isoflurane plus 20 mg·kg -1 ·h -1 propol did not aggravate the cognitive impairment and the ER stress in aging rats with cerebral hypoperusion and being subjected to an ORIF surgery. Conclusions: These data suggest that ER stress contributes to the underlying mechanism of cognitive impairment and the combination of isoflurane and propofol did not aggravate the cognitive impairment and the ER stress in aging rats with cerebral hypoperfusion and being subjected to an ORIF surgery.

scholarly journals The Neuroprotective Effects of Carvacrol on Ethanol-Induced Hippocampal Neurons Impairment via the Antioxidative and Antiapoptotic Pathways

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Peng Wang ◽  
Qian Luo ◽  
Hui Qiao ◽  
Hui Ding ◽  
Yonggang Cao ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Western Blot ◽  
Cognitive Dysfunction ◽  
Hippocampal Neurons ◽  
Morris Water Maze Test ◽  
Oxidative Stress Biomarkers ◽  
Neuroprotective Effects ◽  
Stress Injury

Chronic alcohol consumption causes hippocampal neuronal impairment, which is associated with oxidative stress and apoptosis. Carvacrol is a major monoterpenic phenol found in essential oils from the family Labiatae and has antioxidative stress and antiapoptosis actions. However, the protective effects of carvacrol in ethanol-induced hippocampal neuronal impairment have not been fully understood. We explored the neuroprotective effects of carvacrol in vivo and in vitro. Male C57BL/6 mice were exposed to 35% ethanol for 4 weeks to establish ethanol model in vivo, and hippocampal neuron injury was simulated by 200 mM ethanol in vitro. Morris water maze test was performed to evaluate the cognitive dysfunction. The oxidative stress injury of hippocampal neurons was evaluated by measuring the levels of oxidative stress biomarkers. Histopathological examinations and western blot were performed to evaluate the apoptosis of neurons. The results showed that carvacrol attenuates the cognitive dysfunction, oxidative stress, and apoptosis of the mice treated with ethanol and decreases hippocampal neurons apoptosis induced by ethanol in vitro. In addition, western blot analysis revealed that carvacrol modulates the protein expression of Bcl-2, Bax, caspase-3, and p-ERK, without influence of p-JNK and p-p38. Our results suggest that carvacrol alleviates ethanol-mediated hippocampal neuronal impairment by antioxidative and antiapoptotic effects.

scholarly journals Platycodon grandiflorum Root Protects against Aβ-Induced Cognitive Dysfunction and Pathology in Female Models of Alzheimer’s Disease

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 207
Author(s):  
Yunkwon Nam ◽  
Soo Jung Shin ◽  
Yong Ho Park ◽  
Min-Jeong Kim ◽  
Seong Gak Jeon ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Cognitive Dysfunction ◽  
Hippocampal Neurons ◽  
Hippocampal Formation ◽  
Histopathological Analysis ◽  
Root Extract ◽  
Platycodon Grandiflorum ◽  
5Xfad Mice

Alzheimer’s disease (AD) is a devastating neurodegenerative disease characterized by irreversible cognitive dysfunction. Amyloid beta (Aβ) peptide is an important pathological factor that triggers the progression of AD through accumulation and aggregation, which leads to AD-related pathologies that consequently affect cognitive functions. Interestingly, several studies have reported that Platycodon grandiflorum root extract (PGE), besides exhibiting other bioactive effects, displays neuroprotective, anti-neuroinflammatory, and cognitive-enhancing effects. However, to date, it is not clear whether PGE can affect AD-related cognitive dysfunction and pathogenesis. Therefore, to investigate whether PGE influences cognitive impairment in an animal model of AD, we conducted a Y-maze test using a 5XFAD mouse model. Oral administration of PGE for 3 weeks at a daily dose of 100 mg/kg significantly ameliorated cognitive impairment in 5XFAD mice. Moreover, to elucidate the neurohistological mechanisms underlying the PGE-mediated alleviative effect on cognitive dysfunction, we performed histological analysis of hippocampal formation in these mice. Histopathological analysis showed that PGE significantly alleviated AD-related pathologies such as Aβ accumulation, neurodegeneration, oxidative stress, and neuroinflammation. In addition, we observed a neuroprotective and antioxidant effect of PGE in mouse hippocampal neurons. Our findings suggest that administration of PGE might act as one of the therapeutic agents for AD by decreasing Aβ related pathology and ameliorating Aβ induced cognitive impairment.

Neuroprotective Effects of Salidroside Against Beta-Amyloid-Induced Cognitive Impairment in Alzheimer’s Disease Mice Through the PKC/p38MAPK Pathway

2020 ◽  
Vol 10 (2) ◽  
pp. 212-217
Author(s):  
Wei Li ◽  
Sixia Yang ◽  
Zeping Xie ◽  
Hui Lu ◽  
Junjun Ling ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cognitive Impairment ◽  
Protein Expression ◽  
Cognitive Dysfunction ◽  
Neuronal Damage ◽  
Nissl Staining ◽  
Neuroprotective Effects ◽  
Neural Apoptosis ◽  
P38mapk Pathway

Alzheimer’s disease (AD) is a common neurodegenerative disease as well as the main cause of dementia. A progressive cognitive decline with age is considered as the major manifestation of AD. Amyloid beta-peptide (Aβ) is one of the primary causes leading to cognitive dysfunction in AD. Recent studies have suggested that the activation of PKC/p38MAPK pathway is related to the neurotoxicity induced by β-amyloid. Salidroside is the major active component of Rhodiola crenu-lata, has been reported with widely neuroprotective effects. The protective effects of salidroside against β-amyloid induced neural apoptosis via the MAPKs pathway has been confirmed in the vitro study. The present study aimed to investigate the neuroprotective effects of salidroside through the PKC/p38MAPK pathway in β-amyloid induced AD mice. The results by Y maze showed that salidroside improved Aβ-induced cognitive impairment. Nissl staining results showed that salidroside affected neuronal damage in hippocampus and cerebral cortex of AD mice. Western blot results revealed that salidroside enhanced protein expression of p-PKC, whereas it suppressed protein expression of p-p38MAPK, Bax and cleaved caspase-3. Thus, the present results demonstrated that salidroside ameliorated cognitive dysfunction in Aβ25–35 induced AD mice. And the effects on protein expression of p-PKC and p-p38MAPK contributed to the neuroprotective effects of salidroside against neural apoptosis in AD mice.

Rifampicin Suppresses Amyloid-β Accumulation Through Enhancing Autophagy in the Hippocampus of a Lipopolysaccharide-Induced Mouse Model of Cognitive Decline

2020 ◽  
pp. 1-14
Author(s):  
Lihong Zhu ◽  
Qiongru Yuan ◽  
Zhaohao Zeng ◽  
Ruiyi Zhou ◽  
Rixin Luo ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Mouse Model ◽  
Hippocampal Neurons ◽  
Cognitive Impairments ◽  
Amyloid Β ◽  
Underlying Mechanism ◽  
Autophagosome Formation ◽  
Neuroprotective Effects ◽  
Biochemical Assays ◽  
Cognitive Sequelae

Background: Alzheimer’s disease (AD) is characterized by amyloid-β (Aβ) deposition. The metabolism of Aβ is critically affected by autophagy. Although rifampicin is known to mediate neuroinflammation, the underlying mechanism by which rifampicin regulates the cognitive sequelae remains unknown. Objective: Based on our previous findings that rifampicin possesses neuroprotective effects on improving cognitive function after neuroinflammation, we aimed to examine in this study whether rifampicin can inhibit Aβ accumulation by enhancing autophagy in a mouse model of lipopolysaccharide (LPS)-induced cognitive impairment. Methods: Adult C57BL/6 mice were intraperitoneally injected with rifampicin, chloroquine, and/or LPS every day for 7 days. Pathological and biochemical assays and behavioral tests were performed to determine the therapeutic effect and mechanism of rifampicin on the hippocampus of LPS-induced mice. Results: We found that rifampicin ameliorated cognitive impairments in the LPS-induced mice. In addition, rifampicin attenuated the inhibition of autophagosome formation, suppressed the accumulation of Aβ1–42, and protected the hippocampal neurons against LPS-induced damage. Our results further demonstrated that rifampicin improved the neurological function by promoting autophagy through the inhibition of Akt/mTOR/p70S6K signaling pathway in the hippocampus of LPS-induced mice. Conclusion: Rifampicin ameliorates cognitive impairment by suppression of Aβ1–42 accumulation through inhibition of Akt/mTOR/p70S6K signaling and enhancement of autophagy in the hippocampus of LPS-induced mice.

scholarly journals Sodium 4-Phenylbutyrate Protects Hypoxic-Ischemic Brain Injury via Attenuating Endoplasmic Reticulum Stress in Neonatal Rats

2021 ◽  
Vol 15 ◽  
Author(s):  
Ziyi Wu ◽  
Jiayuan Niu ◽  
Hang Xue ◽  
Shuo Wang ◽  
Ping Zhao
Keyword(s):  
Endoplasmic Reticulum ◽  
Brain Injury ◽  
Er Stress ◽  
Western Blotting ◽  
Hippocampal Neurons ◽  
Neurological Diseases ◽  
Critical Role ◽  
Nissl Staining ◽  
Neuroprotective Effects ◽  
Chemical Chaperone

Neonatal hypoxic-ischemic (HI) brain injury is associated with long-term neurological disorders, and protective strategies are presently scarce. Sodium 4-phenylbutyrate (4-PBA) reportedly acts as a chemical chaperone that alleviates endoplasmic reticulum (ER) stress, which plays a critical role in neurological diseases. The present study aimed to evaluate the neuroprotective effects of 4-PBA on HI-induced neonatal brain injury in a rat model, and to characterize possible underlying mechanisms. The HI brain injury model was established by ligating the left common carotid artery in 7-day-old rats, followed by exposure to 8% oxygen for 2 h. The 4-PBA or vehicle was administered by an intracerebroventricular injection 30 min before HI. The protein expression levels of ER stress markers (GRP78, ATF6, and CHOP) were detected by western blotting at 24 h after HI insult. The activation of cAMP-response element-binding protein (CREB) was evaluated by western blotting and immunofluorescence. TUNEL and Nissl staining were performed to detect the histomorphological changes in the hippocampal neurons at 24 h and 7 days, respectively, after HI injury. From days 29 to 34 after brain HI, rats underwent Morris water maze tests to assess cognitive functioning. The results showed that pretreatment with 4-PBA decreased HI-induced excessive ER stress and neuronal injury. Moreover, CREB activation might be involved in the beneficial effects of 4-PBA on HI-induced learning and memory deficits in rats. In conclusion, the present study suggested a potential therapeutic approach of ER stress inhibition in the treatment of neonatal HI brain injury.

Vitamin D Alleviates Cognitive Dysfunction by Activating the VDR/ERK1/2 Signaling Pathway in an Alzheimer’s Disease Mouse Model

2020 ◽  
Vol 27 (4) ◽  
pp. 178-185
Author(s):  
Zheng Bao ◽  
Xue Wang ◽  
Yuhong Li ◽  
Fumin Feng
Keyword(s):  
Vitamin D ◽  
Cognitive Impairment ◽  
Mouse Model ◽  
Signaling Pathway ◽  
Learning And Memory ◽  
Hippocampal Neurons ◽  
Morphological Changes ◽  
Active Form ◽  
Biologically Active ◽  
Neuroprotective Effects

Objective: Vitamin D (Vit D), a steroid hormone, has been linked to cognitive impairment and dementia, such as Alz­heimer’s disease (AD). 1, 25(OH)2D3 is the biologically active form of Vit D, which has been shown to have neuroprotective effects. This compound is being evaluated as an emerging therapeutic treatment in models of AD. Material and Methods: The present study was designed to investigate whether Vit D could alleviate cognitive impairment in an AD rat model by regulating the VDR/ERK1/2 signaling pathway. Adult male APPswe/PS1ΔE9 rats (n = 40) were randomly divided into 2 groups: the AD group and the Vit D + AD group (20 mice per group), and 40 C57BL/6J age-matched mice were separated into the control (CON) group and the Vit D + CON group (20 mice per group). The Morris water maze and object recognition tests were used to evaluate learning and memory functions of the mice. Hematoxylin and eosin staining was used to evaluate morphological changes in hippocampal neurons. Western blotting was used to evaluate the proteins responsible for these changes. Results: We found that Vit D improved learning and memory abilities and morphological defects in hippocampal neurons. Vit D decreased the gene expression of caspase-3 and Bax and increased the expression of Bcl-2. Vit D also increased the protein expression of VDR and p-ERK1 protein in AD mice. Conclusion: This study provides new clues about the mechanism by which Vit D exerts neuroprotective effects in an AD mouse model.

scholarly journals Protective effects of intracerebroventricular adiponectin against olfactory impairments in an amyloid β1–42 rat model

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Mara A. Guzmán-Ruiz ◽  
Amor Herrera-González ◽  
Adriana Jiménez ◽  
Alan Candelas-Juárez ◽  
Crystal Quiroga-Lozano ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Amyloid Beta ◽  
Rat Model ◽  
Calcium Binding ◽  
Olfactory Dysfunction ◽  
Olfactory Function ◽  
Protective Effects ◽  
Neuroprotective Effects ◽  
Arginase 1 ◽  
Olfactory Impairment

Abstract Background Alzheimer’s disease (AD) is characterized by cognitive impairment that eventually develops into dementia. Amyloid-beta (Aβ) accumulation is a widely described hallmark in AD, and has been reported to cause olfactory dysfunction, a condition considered an early marker of the disease associated with injuries in the olfactory bulb (OB), the hippocampus (HIPP) and other odor-related cortexes. Adiponectin (APN) is an adipokine with neuroprotective effects. Studies have demonstrated that APN administration decreases Aβ neurotoxicity and Tau hyperphosphorylation in the HIPP, reducing cognitive impairment. However, there are no studies regarding the neuroprotective effects of APN in the olfactory dysfunction observed in the Aβ rat model. The aim of the present study is to determine whether the intracerebroventricular (i.c.v) administration of APN prevents the early olfactory dysfunction in an i.c.v Amyloid-beta1–42 (Aβ1–42) rat model. Hence, we evaluated olfactory function by using a battery of olfactory tests aimed to assess olfactory memory, discrimination and detection in the Aβ rat model treated with APN. In addition, we determined the number of cells expressing the neuronal nuclei (NeuN), as well as the number of microglial cells by using the ionized calcium-binding adapter molecule 1 (Iba-1) marker in the OB and, CA1, CA3, hilus and dentate gyrus (DG) in the HIPP. Finally, we determined Arginase-1 expression in both nuclei through Western blot. Results We observed that the i.c.v injection of Aβ decreased olfactory function, which was prevented by the i.c.v administration of APN. In accordance with the olfactory impairment observed in i.c.v Aβ-treated rats, we observed a decrease in NeuN expressing cells in the glomerular layer of the OB, which was also prevented with the i.c.v APN. Furthermore, we observed an increase of Iba-1 cells in CA1, and DG in the HIPP of the Aβ rats, which was prevented by the APN treatment. Conclusion The present study describes the olfactory impairment of Aβ treated rats and evidences the protective role that APN plays in the brain, by preventing the olfactory impairment induced by Aβ1–42. These results may lead to APN-based pharmacological therapies aimed to ameliorate AD neurotoxic effects.

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