CZ-7, a new derivative of Claulansine F, ameliorates 2VO-induced vascular dementia in rats through a Nrf2-mediated antioxidant responses

Zhongfeng Xingnao Liquid ameliorates post-stroke cognitive impairment through sirtuin1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway

The activation of the sirtuin1 (SIRT1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway has been shown to mitigate oxidative stress-induced apoptosis and mitochondrial damage by reducing reactive oxygen species (ROS) levels. Clinical trials have demonstrated that Zhongfeng Xingnao Liquid (ZFXN) ameliorates post-stroke cognitive impairment (PSCI). However, the underlying mechanism, particularly whether it involves protecting mitochondria and inhibiting apoptosis through the SIRT1/Nrf2/HO-1 pathway, remains unclear. This study employed an oxygen-glucose deprivation (OGD) cell model using SH-SY5Y cells and induced PSCI in rats through modified bilateral carotid artery ligation (2VO). The effects of ZFXN on learning and memory, neuroprotective activity, mitochondrial function, oxidative stress, and the SIRT1/Nrf2/HO-1 pathway were evaluated both in vivo and in vitro. Results indicated that ZFXN significantly increased the B-cell lymphoma 2 (Bcl2)/Bcl2-associated X (Bax) ratio, reduced terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling (TUNEL)+ cells, and markedly improved cognition, synaptic plasticity, and neuronal function in the hippocampus and cortex. Furthermore, ZFXN exhibited potent antioxidant activity, evidenced by decreased ROS and malondialdehyde (MDA) content and increased superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels. ZFXN also demonstrated considerable enhancement of mitochondrial membrane potential (MMP), Tom20 fluorescence intensity, adenosine triphosphate (ATP) and energy charge (EC) levels, and mitochondrial complex I and III activity, thereby inhibiting mitochondrial damage. Additionally, ZFXN significantly increased SIRT1 activity and elevated SIRT1, nuclear Nrf2, and HO-1 levels. Notably, these effects were substantially counteracted when SIRT1 was suppressed by the inhibitor EX-527 in vitro. In conclusion, ZFXN alleviates PSCI by activating the SIRT1/Nrf2/HO-1 pathway and preventing mitochondrial damage.

Mechanism of P-Hydroxy Benzyl Alcohol Against Cerebral Ischemia Based on Metabonomics Analysis

Stroke is the leading cause of death and disability worldwide, with ischemic stroke accounting for the majority of these. HBA is the active ingredient in Gastrodia elata and has potential therapeutic effects on central nervous system diseases. In this study, the cell model of cerebral ischemia was replicated by the culture method of oxygen-glucose deprivation/reoxygenation, and the rat model of vascular dementia was established by the two-vessel occlusion method. Metabolomics technology was employed to analyze the metabolic changes in ischemic neurons induced by HBA, and potential therapeutic targets were verified. The protective effects of HBA on ischemic neurons and their mitochondria were examined through multiple indicators, and the related mechanisms were verified. HBA can improve post-ischemic cognitive impairment in rats, and its mechanism is related to the regulation of the choline-activated phospholipase D2/Sirtuin 1/peroxisome proliferator-activated receptor-γ coactivator 1α pathway to improve mitochondrial function and reduce autophagic activity to maintain mitochondrial homeostasis. It is concluded that HBA has a protective effect on neuronal damage and cognitive impairment caused by cerebral ischemia by regulating key metabolites and signaling pathways, and that it provides a new molecular target for the treatment of cerebral ischemia.

Exploring the effects of moxibustion on cognitive function in rats with multiple cerebral infarctions from the perspective of glial vascular unit repairing

Objective

This study aimed to explore the effect of moxibustion at Governor Vessel (GV) acupoints, including Baihui (GV 20), Shenting (GV 24) and Dazhui (GV 14) for 14 days on glial vascular unit (GVU) in rats with multiple microinfarctions (MMI), and to explore its action mechanism.

Methods

The effect and mechanism of moxibustion on vascular dementia (VD) were studied in MMI rats by means of behavioral and molecular biology experiments.

Results

Rats receiving MMI showed impairment of memory function, reduction of cerebral blood flow, damage of blood-brain barrier (BBB) integrity and increased brain mass. MMI also increased neuronal degeneration in the hippocampus. Notably, levels of glial fibrillary acidic protein (GFAP) and complement component 3 significantly increased, but those of Connexin43 (CX43) and platelet derived growth factor receptor β (PDGFRβ) significantly decreased in the hippocampus of the rats receiving MMI. Moxibustion, as well as oxiracetam (ORC) treatment improved memory function and neuronal degeneration, ameliorated BBB integrity, increased cerebral blood flow and decreased brain mass. In addition, moxibustion as well as oxiracetam (ORC) treatment reduced the decrease of CX43 protein and increased PDGFRβ protein level in the hippocampus of MMI rats. Moreover, moxibustion treatment reversed MMI-induced increase of the GFAP/CX43 ratio in vascular structural units. Importantly, after PDGFRβ inhibition, VD rats treated with moxibustion had impaired learning and memory, decreased cerebral blood flow, and BBB disruption.

Conclusion

Moxibustion treatment at various GV acupoints improved cerebral blood flow and repaired BBB function in rats with MMI, likely through protecting GVU.

Natural herbal extract roles and mechanisms in treating cerebral ischemia: A systematic review

Background

Stroke has been the focus of medical research due to its serious consequences and sequelae. Among the tens of millions of new stroke patients every year, cerebral ischemia patients account for the vast majority. While cerebral ischemia drug research and development is still ongoing, most drugs are terminated at preclinical stages due to their unacceptable toxic side effects. In recent years, natural herbs have received considerable attention in the pharmaceutical research and development field due to their low toxicity levels. Numerous studies have shown that natural herbs exert actions that cannot be ignored when treating cerebral ischemia.

Methods

We reviewed and summarized the therapeutic effects and mechanisms of different natural herbal extracts on cerebral ischemia to promote their application in this field. We used keywords such as "natural herbal extract," "herbal medicine," "Chinese herbal medicine" and "cerebral ischemia" to comprehensively search PubMed, ScienceDirect, ScienceNet, CNKI, and Wanfang databases, after which we conducted a detailed screening and review strategy.

Results

We included 120 high-quality studies up to 10 January 2024. Natural herbal extracts had significant roles in cerebral ischemia treatments via several molecular mechanisms, such as improving regional blood flow disorders, protecting the blood-brain barrier, and inhibiting neuronal apoptosis, oxidative stress and inflammatory responses.

Conclusion

Natural herbal extracts are represented by low toxicity and high curative effects, and will become indispensable therapeutic options in the cerebral ischemia treatment field.

Brozopine ameliorates cognitive impairment via upregulating Nrf2, antioxidation and anti-inflammation activities

Oxidative stress and inflammation are crucial factors contributing to the occurrence and development of vascular dementia (VD). In a previous study, we demonstrated that brozopine (BZP) is an anti-ischemic drug. In this study, a model of VD in rats with modified permanent bilateral common carotid artery occlusion (2-VO) was established in vivo, a model of cellular excitotoxicity/oxidative stress was established via L-glutamate-induced PC12 cell injury, a model of neuroinflammation was established in LPS-induced BV2 cells in vitro, and the ameliorative effect of BZP on cognitive impairment was assessed. BZP treatment improved memory deficit in VD rats through inhibiting Ca2+overload and the levels of oxidative stress, ferroptosis, and inflammatory markers (IL-1β, IL-6, and COX-2) in different brain regions. Additionally, we found that the levels of inflammatory markers in the plasma were also reduced in the VD rats. BZP was further found to have antioxidative stress, antiferroptosis (ferroptosis markers: GPX4, P53, and ACSL4), and antineuroinflammatory effects in PC12 and BV2 cells. Its mechanisms of action were found to be related to the activation of the Nrf2/TLR4/NF-κB pathway; the protective effect of BZP was partially inhibited after using Nrf2-specific inhibitors. Thus, BZP has therapeutic properties for the potential mitigation of cognitive impairment.

A novel phthalein component ameliorates neuroinflammation and cognitive dysfunction by suppressing the CXCL12/CXCR4 axis in rats with vascular dementia

ETHNOPHARMACOLOGICAL RELEVANCE

Chuanxiong, a plant of the Umbelliferae family, is a genuine medicinal herb from Sichuan Province. Phthalides are one of its main active components and exhibit good protective effect against cerebrovascular diseases. However, the mechanism by which phthalides exert neuroprotective effects is still largely unclear.

AIM OF THE STUDY

In this study, we extracted a phthalein component (named as QBT) from Ligusticum Chuanxiong, and investigated its neuroprotective effects against vascular dementia (VaD) rats and the underlying mechanism, focusing on the chemokine 12 (CXCL12)/chemokine (C-X-C motif) receptor 4 (CXCR4) axis.

METHODS

A rat model of VaD was established, and treated with QBT. Cognitive dysfunction in VaD rats was assessed using the Y-maze, new object recognition, and Morris water maze tests. Neuronal damage and inflammatory response in VaD rats were examined through Nissl staining, immunofluorescence, enzyme-linked immunospecific assay, and western blotting analysis. Furthermore, the effects of QBT on CXCL12/CXCR4 axis and its downstream signaling pathways, Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT3) and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT)/nuclear factor-κB (NF-κB), were investigated in VaD rats and BV2 microglial cells exposed to oxygen glucose deprivation.

RESULTS

QBT significantly alleviated cognitive dysfunction and neuronal damage in VaD rats, along with inhibition of VaD-induced over-activation of microglia and astrocytes and inflammatory response. Moreover, QBT exhibited anti-inflammatory effects by inhibiting the CXCL12/CXCR4 axis and its downstream JAK2/STAT3 and PI3K/AKT/NF-κB pathways, thereby attenuating the neuroinflammatory response both in vivo and in vitro.

CONCLUSION

QBT effectively mitigated neuronal damage and cognitive dysfunction in VaD rats, exerting neuroprotective effects by suppressing neuroinflammatory response through inhibition of the CXCL12/CXCR4 axis.

7, 8-dihydroxyflavone Ameliorates Cholinergic Dysfunction, Inflammation, Oxidative Stress, and Apoptosis in a Rat Model of Vascular Dementia

Vascular dementia (VD) is a degenerative cerebrovascular disorder associated with progressive cognitive decline. Previous reports have shown that 7,8-dihydroxyflavone (7,8-DHF), a well-known TrkB agonist, effectively ameliorates cognitive deficits in several disease models. Therefore, this study investigated the protective effects of 7,8-DHF against 2-VO-induced VD. VD was established in rats using the permanent bilateral carotid arteries occlusion (two-vessel occlusion, 2-VO) model. 7,8-DHF (5, 10, and 20 mg/kg) and Donepezil (10 mg/kg) were administered for 4 weeks. Memory function was assessed by the novel objective recognition task (NOR) and Morris water maze (MWM) tests. Inflammatory (TNF-α, IL-1β, and NF-kβ), oxidative stress, and apoptotic (BAX, BCL-2, caspase-3) markers, along with the activity of choline acetylcholinesterase (AChE) was assessed. p-AKT, p-CREB, BDNF, and neurotransmitter (NT) (GLU, GABA, and ACh) levels were also analyzed in the hippocampus of 2-VO rats. Our results show that 7,8-DHF effectively improved memory performance and cholinergic dysfunction in 2-VO model rats. Furthermore, 7,8-DHF treatment also increased p-AKT, p-CREB, and BDNF levels, suppressed oxidative, inflammatory, and apoptotic markers, and restored altered NT levels in the hippocampus. These findings imply that 7, 8-DHF may act via multiple mechanisms and as such serve as a promising neuroprotective agent in the context of VD.

Folic acid alleviated oxidative stress-induced telomere attrition and inhibited apoptosis of neurocytes in old rats

PURPOSE

Oxidative stress has been reported to cause telomere attrition, which triggers cell apoptosis. Apoptosis of neurocytes may play an essential role in the pathogenesis of neurodegenerative diseases. This study hypothesized that folic acid (FA) supplementation decreased neurocyte apoptosis by alleviating oxidative stress-induced telomere attrition in 25-month-old Sprague Dawley (SD) rats.

METHODS

Three-month-old male SD rats were randomly divided into four diet groups by different concentrations of folic acid in equal numbers, with intervention for 22 months. Folate, homocysteine (Hcy), reactive oxygen species (ROS) levels, antioxidant activities, and telomere length in the brain tissues were tested at 11, 18, and 22 months of intervention, and 8-hydroxy-deoxyguanosine (8-OHdG) levels, neurocyte apoptosis and telomere length in the cerebral cortex and hippocampal regions were tested during the 22-month intervention. An automated chemiluminescence system, auto-chemistry analyzer, Q-FISH, qPCR, and TUNEL assay were used in this study.

RESULTS

The rats had lower folate concentrations and higher Hcy, ROS, and 8-OHdG concentrations in brain tissue with aging. However, FA supplementation increased folate concentrations and antioxidant activities while decreasing Hcy, ROS, and 8-OHdG levels in rat brain tissue after 11, 18, and 22 months of intervention. Furthermore, FA supplementation alleviated telomere length shortening and inhibited neurocyte apoptosis during the 22-month intervention.

CONCLUSION

FA supplementation alleviated oxidative stress-induced telomere attrition and inhibited apoptosis of neurocytes in 25-month-old rats.

Mumefural Improves Recognition Memory and Alters ERK-CREB-BDNF Signaling in a Mouse Model of Chronic Cerebral Hypoperfusion

Cognitive impairment resulting from chronic cerebral hypoperfusion (CCH) is known as vascular dementia (VaD) and is associated with cerebral atrophy and cholinergic deficiencies. Mumefural (MF), a bioactive compound found in a heated fruit of Prunus mume Sieb. et Zucc, was recently found to improve cognitive impairment in a rat CCH model. However, additional evidence is necessary to validate the efficacy of MF administration for treating VaD. Therefore, we evaluated MF effects in a mouse CCH model using unilateral common carotid artery occlusion (UCCAO). Mice were subjected to UCCAO or sham surgery and orally treated with MF daily for 8 weeks. Behavioral tests were used to investigate cognitive function and locomotor activity. Changes in body and brain weights were measured, and levels of hippocampal proteins (brain-derived neurotrophic factor (BDNF), extracellular signal-regulated kinase (ERK), cyclic AMP-response element-binding protein (CREB), and acetylcholinesterase (AChE)) were assessed. Additionally, proteomic analysis was conducted to examine the alterations in protein profiles induced by MF treatment. Our study showed that MF administration significantly improved cognitive deficits. Brain atrophy was attenuated and MF treatment reversed the increase in AChE levels. Furthermore, MF significantly upregulated p-ERK/ERK, p-CREB/CREB, and BDNF levels after UCCAO. Thus, MF treatment ameliorates CCH-induced cognitive impairment by regulating ERK/CREB/BDNF signaling, suggesting that MF is a therapeutic candidate for treating CCH.

Profiling inflammatory mechanisms, hyperphosphorylated tau of hippocampal tissue and spatial memory following vitamin D3 treatment in the mice model of vascular dementia

BACKGROUND

The aim of this study was to investigate the effect of vitamin D3 (VitD3) on inflammatory mechanisms, hyperphosphorylated tau (p-tau) in the hippocampus, and cognitive impairment of the mouse model of vascular dementia (VaD).

METHODS

In this study, 32 male mice were randomly assigned to the control, VaD, VitD3 (300 IU/Kg/day), and VitD3 (500 IU/Kg/day) groups. VaD and VitD3 groups were gavaged daily for 4 weeks with a gastric needle. For biochemical assessments, blood samples and the hippocampus were isolated. IL-1β and TNF-α were analyzed by ELISA, and p-tau and other inflammatory molecules were measured by western blot.

RESULTS

VitD3 supplements significantly (P < 0.05) decreased the level of inflammatory factors in the hippocampus and prevented apoptosis. However, regarding p-tau in hippocampal tissue, this decrease was not statistically significant (P > 0.05). The results of behavioral assessments showed that VitD3 significantly improved the spatial memory of treated mice.

CONCLUSION

These results suggest that the neuroprotective effects of VitD3 are mainly associated with their anti-inflammatory effects.

CZK, a novel alkaloid derivative from Clausena lansium, alleviates ischemic stroke injury through Nrf2-mediated antioxidant effects

Anti-oxidant stress is a potential strategy for the treatment of ischemic stroke. Here, we found a novel free radical scavenger termed as CZK, which is derived from alkaloids contained in Clausena lansium. In this study, we first compared cytotoxicity and biological activity between CZK and its parent's compound Claulansine F. It was found that CZK had lower cytotoxicity and improved anti-oxygen-glucose deprivation/reoxygenation (OGD/R) injury than its parent's compound. Free radical scavenging test showed that CZK had a strong inhibitory effect on hydroxyl free radicals with the IC₅₀ of 77.08 nM. Intravenous injection of CZK (50 mg/kg) significantly alleviated ischemia-reperfusion injury, manifested by reduced neuronal damage and decreased oxidative stress. Consistent with the findings, the activities of superoxide dismutase (SOD) and reduced glutathione (GSH) were increased. Molecular docking predicted that CZK might be combined with nuclear factor erythroid 2-related factor 2 (Nrf2) complex. Our results also confirmed that CZK upregulated the contents of Nrf2 and its target gene products Heme Oxygenase-1 (HO-1), and NAD(P)H: Quinone Oxidoreductase 1 (NQO1). In conclusion, CZK had a potential therapeutic effect for ischemic stroke by activating Nrf2-mediated antioxidant system.

Sulforaphane promotes white matter plasticity and improves long-term neurological outcomes after ischemic stroke via the Nrf2 pathway

AIMS

Post-stroke cognitive impairment (PSCI) is a common condition following ischemic stroke. Neuronal loss and white matter injury are among the most common neuropathological characteristics in patients with PSCI. The present study tested our hypothesis that activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) reduces neuronal loss, white matter injury, and neurobehavioral deficits in a mouse model of PSCI and investigated the underlying protective mechanisms.

METHODS

PSCI was modeled in wildtype (WT) and Nrf2 knockout (KO), male and female mice, by distal middle cerebral artery occlusion (dMCAO), with intraperitoneal injections of the Nrf2 activator sulforaphane (Sfn) or vehicle. Long-term (35 days) sensorimotor and cognitive performances, white matter integrity, oligodendrogenesis by BrdU incorporation, and neurite sprouting using anterograde tract-tracing were evaluated up to 35 days after dMCAO. Neuronal apoptosis was evaluated three days after dMCAO. In vitro, primary neuronal cultures were applied to validate the in vivo findings.

RESULTS

Compared to vehicle-injected controls, Sfn treatment improved long-term sensorimotor and cognitive deficits after dMCAO in WT male and female mice. Sfn-treated WT mice also had less myelin loss/axonal injury and showed evidence of Nrf2 activation. Sfn treatment failed to provide the same level of protection in Nrf2 KO mice. Mechanistically, the ability of Sfn to reduce neuronal death after ischemia in vitro and in vivo, augment axonal sprouting and enhance oligodendrogenesis after dMCAO was dependent on Nrf2 activation.

CONCLUSION

Our results support that Nrf2 is critical for Sfn-afforded neuroprotection after ischemic stroke. Thus, targeting Nrf2 may be a promising strategy for the treatment of PSCI.

Discovering a Multi-Component Combination against Vascular Dementia from Danshen-Honghua Herbal Pair by Spectrum-Effect Relationship Analysis

The Danshen-Honghua (DH) herbal pair exhibits a synergistic effect in protecting the cerebrovascular system from ischemia/reperfusion injury, but the therapeutic effect on vascular dementia (VaD) has not been clarified, and the main active ingredient group has not been clarified. In this work, the chemical constituents in DH herbal pair extract were characterized by UHPLC-QTOF MS, and a total of 72 compounds were identified. Moreover, the DH herbal pair alleviated phenylhydrazine (PHZ)-induced thrombosis and improved bisphenol F (BPF)- and ponatinib-induced brain injury in zebrafish. Furthermore, the spectrum-effect relationship between the fingerprint of the DH herbal pair and the antithrombotic and neuroprotective efficacy was analyzed, and 11 chemical components were screened out as the multi-component combination (MCC) against VaD. Among them, the two compounds with the highest content were salvianolic acid B (17.31 ± 0.20 mg/g) and hydroxysafflor yellow A (15.85 ± 0.19 mg/g). Finally, we combined these 11 candidate compounds as the MCC and found that it could improve thrombosis and neuronal injury in three zebrafish models and rat bilateral common carotid artery occlusion (BCCAO) model, which had similar efficacy compared to the DH herbal pair. This study provides research ideas for the treatment of VaD and the clinical application of the DH herbal pair.

Açai Berry Mitigates Vascular Dementia-Induced Neuropathological Alterations Modulating Nrf-2/Beclin1 Pathways

The second-most common cause of dementia is vascular dementia (VaD). The majority of VaD patients experience cognitive impairment, which is brought on by oxidative stress and changes in autophagic function, which ultimately result in neuronal impairment and death. In this study, we examine a novel method for reversing VaD-induced changes brought on by açai berry supplementation in a VaD mouse model. The purpose of this study was to examine the impact of açai berries on the molecular mechanisms underlying VaD in a mouse model of the disease that was created by repeated ischemia-reperfusion (IR) of the whole bilateral carotid artery. Here, we found that açai berry was able to reduce VaD-induced behavioral alteration, as well as hippocampal death, in CA1 and CA3 regions. These effects are probably due to the modulation of nuclear factor erythroid 2-related factor 2 (Nrf-2) and Beclin-1, suggesting a possible crosstalk between these molecular pathways. In conclusion, the protective effects of açai berry could be a good supplementation in the future for the management of vascular dementia.

Phyto-Carbazole Alkaloids from the Rutaceae Family as Potential Protective Agents against Neurodegenerative Diseases

Plant-derived (phyto) carbazole alkaloids are an important class of compounds, presented in the family of Rutaceae (Genera Murraya, Clausena, Glycosmis, Micromelum and Zanthoxylum). Due to several significant biological activities, such as antitumor, antibacterial, antiviral, antidiabetic, anti-HIV and neuroprotective activities of the parent skeleton (3-methylcarbazole), carbazole alkaloids are recognized as an important class of potential therapeutic agents. Neurodegenerative diseases (NDs) may exhibit a vast range of conditions, affecting neurons primarily and leading ultimately to the progressive losses of normal motor and cognitive functions. The main pathophysiological indicators of NDs comprise increasing atypical protein folding, oxidative stresses, mitochondrial dysfunctions, deranged neurotransmissions and neuronal losses. Phyto-carbazole alkaloids can be investigated for exerting multitarget approaches to ameliorating NDs. This review presents a comprehensive evaluation of the available scientific literature on the neuroprotective mechanisms of phyto-carbazole alkaloids from the Rutaceae family in ameliorating NDs.

Comparison of Cognitive Performance and Cardiac Function Between Three Different Rat Models of Vascular Dementia

PURPOSE

Establishing an ideal animal model is essential for studying the pathogenesis, prevention and treatment of vascular dementia (VD). The present study was designed to compare the differences of behavior, cerebral blood flow (CBF), cardiac output and the levels of myocardial enzyme of three different VD rat models.

METHODS

The rats were randomly divided into sham-operated group (SHAM), permanent bilateral common carotid artery occlusion group (BCCAO), BCCAO combined with sodium nitroprusside (2.0mg·kg^-1) group (BCCAO+2.0SNP) and BCCAO combined with sodium nitroprusside (2.5mg·kg^-1) group (BCCAO+2.5SNP). After operation, Morris water maze test, echocardiographic evaluation and the measurement of CBF were performed, then the levels of myocardial enzymes in serum were assessed during euthanasia.

RESULTS

Compared with SHAM rats, the three VD model rats showed different degrees of cognitive impairment, lower cardiac output and CBF, and BCCAO rats showed higher levels of myocardial enzymes. Compared with BCCAO rats, the spatial learning ability of BCCAO+2.0SNP rats and BCCAO+2.5SNP rats was more severely impaired, while the levels of myocardial enzymes of BCCAO+2.0SNP rats were lower. Compared with BCCAO+2.0SNP rats, BCCAO+2.5SNP rats showed no significant difference in cognitive function and cardiac function.

CONCLUSION

Our present study demonstrated that all of the three different VD rat models exhibited cognitive and cardiac function impairment. The BCCAO+2.0SNP model and BCCAO+2.5SNP model damaged the spatial learning ability more seriously. The BCCAO+2.5SNP model caused more comprehensive cognitive impairment. In addition, the BCCAO+2.0SNP model and BCCAO+2.5SNP model might cause more serious damage to cardiac function.

Salvianolic acid A relieves cognitive disorder after chronic cerebral ischemia: Involvement of Drd2/Cryab/NF-κB pathway

Chronic cerebral ischemia (CCI) refers to long-term hypoperfusion of cerebral blood flow with the main clinical manifestations of progressive cognitive impairment. The pathological mechanism of CCI is complex, and there is a lack of effective treatments. Salvianolic acid A (SalA) is a neuroprotective extract of Salvia miltiorrhiza with the effects of anti-inflammation and anti-apoptosis. In this study, the effect of SalA on cognitive function and Drd2/Cryab/NF-κB signaling pathway in rats with CCI was investigated. Morris water maze and open field test were used to observe the effects of SalA on the cognitive function of CCI rats. The pathological changes in the brain were observed by HE, Nissl, and LFB staining. TUNEL staining, enzyme-linked immunosorbent assay, and western blot analysis were used to detect the inflammatory and apoptosis in the cortex and hippocampus. The expression of Drd2/Cryab/NF-κB pathway-related molecules and Drd2 localization were detected by western blotting and dual immunofluorescence, respectively. SH-SY5Y cells were exposed to chronic hypoglycemic and hypoxic injury in vitro, and Drd2 inhibitor haloperidol was used to verify the involved pathway. The results showed that SalA could improve the cognitive function of CCI rats, reduce pathological damage of cortex and hippocampus, inhibit neuroinflammation and apoptosis, and suppress the activation of NF-κB by regulating Drd2/Cryab pathway. And SalA inhibited NF-κB activation and nuclear translocation in SH-SY5Y cells by upregulating Drd2/Cryab pathway, which was reversed by haloperidol interference. In conclusion, SalA could relieve CCI-induced cognitive impairment in rats, at least partly through the Drd2/Cryab/NF-κB pathway.

Puerarin Alleviates Vascular Cognitive Impairment in Vascular Dementia Rats

Cerebral ischemia triggers vascular dementia (VD), which is characterized by memory loss, cognitive deficits, and vascular injury in the brain. Puerarin (Pur) represents the major isoflavone glycoside of Radix Puerariae, with verified neuroprotective activity and cardiovascular protective effects. However, whether Pur ameliorates cognitive impairment and vascular injury in rats with permanent occlusion of bilateral common carotid arteries (BCCAO) remains unknown. This work aimed to assess Pur's effects on BCCAO-induced VD and to dissect the underlying mechanisms, especially examining the function of transient receptor potential melastatin-related 2 (TRPM2) in alleviating cognitive deficits and vascular injuries. Rats with BCCAO developed VD. Pur (50, 100, and 150 mg/kg) dose-dependently attenuated the pathological changes, increased synaptic structural plasticity in the dorsal CA1 hippocampal region and decreased oxidative stress, which eventually reduced cognitive impairment and vascular injury in BCCAO rats. Notably, Pur-improved neuronal cell loss, synaptic structural plasticity, and endothelial vasorelaxation function might be mediated by the reactive oxygen species (ROS)-dependent TRPM2/NMDAR pathway, evidenced by decreased levels of ROS, malondialdehyde (MDA), Bax, Bax/Bcl2, and TRPM2, and increased levels of superoxide dismutase (SOD), Bcl2, and NR2A. In conclusion, Pur has therapeutic potential for VD, alleviating neuronal cell apoptosis and vascular injury, which may be related to the ROS-dependent TRPM2/NMDAR pathway.

Dimethyl fumarate improves cognitive deficits in chronic cerebral hypoperfusion rats by alleviating inflammation, oxidative stress, and ferroptosis via NRF2/ARE/NF-κB signal pathway

Cerebrovascular disease and its risk factors cause persistent decrease of cerebral blood flow, chronic cerebral hypoperfusion (CCH) is the major foundation of vascular cognitive impairment (VCI). The hippocampus is extremely vulnerable to cerebral ischemia and hypoxia. Oxidative stress and neuroinflammation injury are important pathophysiological mechanisms of this process, which is closely related to hippocampal neurons damage and loss. Dimethyl fumarate (DMF), an FDA-approved therapeutic for multiple sclerosis (MS), plays a protective role in multiple neurological disorders. Studies have shown that DMF exerts anti-inflammatory and antioxidant effects via the NRF2/ARE/NF-κB signaling pathway. Thus, this study aimed to evaluate the neuroprotective effect of DMF in the CCH rat model. Ferroptosis, a novel defined iron-dependent cell death form, were found to be strongly associated with the pathophysiology of CCH. Emerging evidences have shown that inhibition of ferroptosis by targeting NRF2 exerted neuroprotective effect in neurodegeneration diseases. We also investigated whether DMF can alleviate cognitive deficits through inhibition of ferroptosis by the NRF2 signaling pathway in this study. DMF was intragastric for consecutive five weeks (100 mg/kg/day). Then behavior test and histological, molecular, and biochemical analysis were performed. We found that DMF treatment significantly improved cognitive deficits and partially reversed hippocampus neuronal damage and loss caused by CCH. And DMF treatment decreased hippocampus IL-1β, TNF-α, and IL-6 pro-inflammatory cytokines concentration, and mediated the NF-κB signaling pathway. And DMF also alleviated hippocampus oxidative stress through reducing MDA, and increasing GSH and SOD levels, which are also closely associated with ferroptosis. Besides, DMF treatment reduced the expression of PTGS2, and increased the expression of FTH1 and xCT, and the iron content is also reduced, which were the important features related to ferroptosis. Furthermore, DMF activated the NRF2/ARE signaling pathway and upregulated the expression of HO-1, NQO1 and GPX4. These outcomes indicated that DMF can improve cognitive impairment in rats with CCH, possibly through alleviating neuroinflammation, oxidative stress damage and inhibiting ferroptosis of hippocampal neurons. Overall, our results provide new evidence for the neuroprotective role of DMF.

Targeting redox-altered plasticity to reactivate synaptic function: A novel therapeutic strategy for cognitive disorder

Redox-altered plasticity refers to redox-dependent reversible changes in synaptic plasticity via altering functions of key proteins, such as N-methyl-d-aspartate receptor (NMDAR). Age-related cognitive disorders includes Alzheimer's disease (AD), vascular dementia (VD), and age-associated memory impairment (AAMI). Based on the critical role of NMDAR-dependent long-term potentiation (LTP) in memory, the increase of reactive oxygen species in cognitive disorders, and the sensitivity of NMDAR to the redox status, converging lines have suggested the redox-altered NMDAR-dependent plasticity might underlie the synaptic dysfunctions associated with cognitive disorders. In this review, we summarize the involvement of redox-altered plasticity in cognitive disorders by presenting the available evidence. According to reports from our laboratory and other groups, this "redox-altered plasticity" is more similar to functional changes rather than organic injuries, and strategies targeting redox-altered plasticity using pharmacological agents might reverse synaptic dysfunctions and memory abnormalities in the early stage of cognitive disorders. Targeting redox modifications for NMDARs may serve as a novel therapeutic strategy for memory deficits.

Claulansine F-Donepezil Hybrids as Anti-Alzheimer's Disease Agents with Cholinergic, Free-Radical Scavenging, and Neuroprotective Activities

The multifactorial nature of Alzheimer's disease (AD) calls for the development of multitarget agents addressing key pathogenic processes. A total of 26 Claulansine F-donepezil hybrids were designed and synthesized as multitarget drugs. Among these compounds, six compounds exhibited excellent acetylcholinesterase (AChE) inhibitory activity (half maximal inhibitory concentration (IC50) 1.63-4.62 μM). Moreover, (E)-3-(8-(tert-Butyl)-3,3-dimethyl-3,11-dihydropyrano[3,2-a]carbazol-5-yl)-N-((1-(2-chlorobenzyl)piperidin-4-yl)methyl)acrylamide (6bd) exhibited better neuroprotective effects against OGD/R (oxygen-glucose deprivation/reoxygenation) than lead compound Claulansine F. Furthermore, 6bd could cross the blood-brain barrier in vitro. More importantly, compared to edaravone, 6bd had stronger free-radical scavenging activity. Molecular docking studies revealed that 6bd could interact with the catalytic active site of AChE. All of these outstanding in vitro results indicate 6bd as a leading structure worthy of further investigation.

Dimethyl fumarate attenuates 2-VO-induced vascular dementia via activating the Nrf2 signaling pathway in rats

BACKGROUND

Chronic cerebral hypoperfusion (CCH) induced oxidative stress and inflammation is known to be implicated in the pathogenesis of vascular dementia. The nuclear factor erythroid 2-related factor 2 (Nrf2) has emerged as a potential therapeutic target for neuroprotection. In the present study, we investigated the beneficial effects of dimethyl fumarate (DMF), an Nrf2 activator in an experimental model of vascular dementia.

METHODS

Permanent occlusion of the bilateral common carotid arteries (2-VO) was performed to induce CCH in adult male Sprague-Dawley rats. DMF (15, 30, and 60 mg/kg) was administered for 4 weeks. Cognitive performance was assessed using the Morris water maze (MWM) and novel object (NOR) tests. After behavior tests, various oxidative and inflammatory markers were assessed in the hippocampus.

RESULTS

The obtained results indicate that treatment with DMF significantly improved 2 VO-induced cognitive deficits. DMF decreased MDA (p < 0.001), protein carbonyl (PCO) contents (p < 0.001), and acetylcholinesterase (p < 0.01) activities, and inhibited inflammatory markers (TNF-α, IL-1β, NF-κβ, and COX-2) levels. Furthermore, our results showed that DMF augmented GSH (p < 0.001) levels and SOD (p < 0.05), CAT, and GSH-Px (p < 0.001) activities in the hippocampus. Nrf2 (p < 0.05) and its downstream targets HO-1 levels (p < 0.01) and NQO1 (p < 0.05) levels were also up-regulated after DMF treatment.

CONCLUSION

Taken together, the results demonstrate that DMF could serve as a promising neuroprotective agent for treating vascular dementia.

ShenmaYizhi Decoction Improves the Mitochondrial Structure in the Brain and Ameliorates Cognitive Impairment in VCI Rats via the AMPK/UCP2 Signaling Pathway

BACKGROUND

ShenmaYizhi decoction (SMYZD) is an effective prescription of traditional Chinese medicine used to treat vascular dementia (VD). Modern research methods have identified its active ingredients clearly as gastrodin, ferulic acid, ginsenosides, and β-sitosterol. Chronic cerebral hypoperfusion is a driving factor or risk factor for VD, which leads to the disturbance of mitochondrial structure and function.

PURPOSE

To observe whether SMYZD improves cognitive impairment by improving mitochondrial structure and function.

METHODS

Forty adult rats with vascular cognitive impairment (VCI) caused by the bilateral ligation of common carotid arteries were divided into four groups randomly, including the model group, donepezil group, and low-dose and high-dose SMYZD groups, with 10 rats in each group. Additionally, a sham group was established with 10 rats as the control group. The treatment groups were administered donepezil and two different dosages of SMYZD. The donepezil group was administered 0.45 mg/kg/d donepezil, and the SMYZ-L group was administered 2.97 g/kg/d SMYZ, which were equivalent to the clinical dosage. The SMYZ-H group was administered 11.88 g/kg/d SMYZ, which is 4 times higher than the clinically equivalent dosage. A sham-operated group was used as the control group and administered an equal volume of distilled water. The rats were treated by gavage for 8 consecutive weeks. Morris water maze (MWM) test was performed to evaluate the learning and memory ability. The mitochondria of brain tissue were extracted from brain for further test. Mitochondrial morphology and the signal path of AMPK/PPARα/PGC-1α/UCP2 in mitochondria were detected.

RESULTS

With the SMYZD intervention, behavioral performance of rats and pathological changes of mitochondria of brain tissue were significantly improved. In the serum, SOD, GSH-Px, and GSH activities were increased, and the MDA content was decreased. Moreover, the AMPK, PPARα, PGC-1α, UCP2, and ATP5A mRNA and protein expression levels were also reversed by SMYZD.

CONCLUSION

SMYZD may provide a potential therapeutic strategy via activating the AMPK/PPARα/PGC-1α/UCP2 signal pathway to improve mitochondrial structure and energy metabolism thereby alleviate vascular cognitive impairment.

Nuclear receptor TLX may be through regulating the SIRT1/NF-κB pathway to ameliorate cognitive impairment in chronic cerebral hypoperfusion

BACKGROUND

Chronic cerebral hypoperfusion (CCH) is a common pathophysiological mechanism in neurodegenerative diseases, such as Alzheimer's disease and vascular dementia. The orphan nuclear receptor TLX plays an important role in neural development, adult neurogenesis and cognition. The aim of this study was to investigate the neuroprotective effects of TLX on cognitive dysfunction, hippocampal neurogenesis and neuroinflammation in a rat model of CCH and to assess the possible mechanisms.

METHODS

Permanent bilateral common carotid artery occlusion (2-VO) was used to establish a model of CCH. Stereotaxic injection of an adeno-associated virus vector expressing TLX was used to overexpress TLX in the hippocampus. Cognitive function was evaluated by the Morris Water Maze test. Immunofluorescent staining was used to assess hippocampal neurogenesis. The effects of overexpression of TLX on SIRT1 and inflammatory cytokines were analyzed with qRT-PCR and western blot.

RESULT

After 2-VO, CCH rats exhibited cognitive impairment and reduction of hippocampal TLX levels. Overexpression of TLX ameliorated cognitive impairments with increasing number of BrdU + cells and BrdU + NeuN + cells in DG. Furthermore, TLX rescued the reduced SIRT1 usually induced by CCH. Additionally, TLX also inhibited the expression of inflammatory cytokines such as NF-κB and IL-1β.

CONCLUSIONS

The present findings suggested that TLX exerted protective effects against cognitive deficits induced by CCH. The possible mechanisms of TLX may be through regulating the SIRT1/NF-κB pathway, promoting hippocampal neurogenesis and inhibiting the neuroinflammatory response.

Targeting Transcription Factor Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) for the Intervention of Vascular Cognitive Impairment and Dementia

Vascular cognitive impairment and dementia (VCID) is an age-related, mild to severe mental disability due to a broad panel of cerebrovascular disorders. Its pathobiology involves neurovascular dysfunction, blood-brain barrier disruption, white matter damage, microRNAs, oxidative stress, neuroinflammation, and gut microbiota alterations, etc. Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of redox status and controls the transcription of a panel of antioxidative and anti-inflammatory genes. By interacting with NF-κB (nuclear factor-κB), Nrf2 also fine-tunes the cellular oxidative and inflammatory balance. Aging is associated with Nrf2 dysfunction, and increasing evidence has proved the role of Nrf2 in mitigating the VCID process. Based on VCID pathobiologies and Nrf2 studies from VCID and other brain diseases, we point out several hypothetical Nrf2 targets for VCID management, including restoration of endothelial function and neurovascular coupling, preservation of blood-brain barrier integrity, reduction of amyloidopathy, promoting white matter integrity, and mitigating oxidative stress and neuroinflammation. Collectively, the Nrf2 pathway could be a promising direction for future VCID research. Targeting Nrf2 would shed light on VCID managing strategies.

Effects and Mechanisms of Five Psoralea Prenylflavonoids on Aging-Related Diseases

During the aging process, senescent cells gradually accumulate in the organs; they secrete proinflammatory cytokines and other factors, collectively known as the senescence-associated secretory phenotype (SASP). SASP secretions contribute to “inflammaging,” which is a state of chronic, systemic, sterility, low-grade inflammatory microenvironment and a key risk factor in the development of aging-related diseases. Fructus psoraleae is a traditional Chinese medical herb best known for delaying aging and treating osteoporosis. Prenylflavonoids from fructus psoraleae are the main bioactive compounds responsible for its pharmacological applications, such as beaching, bavachinin, bavachalcone, isobavachalcone, and neobavaisoflavone. In previous decades, there have been some promising studies on the pharmacology of fructus psoraleae. Here, we focus on the anti-inflammatory and antiaging diseases of five psoralea prenylflavonoids, such as cardiovascular protection, diabetes and obesity intervention, neuroprotection, and osteoporosis, and discuss the mechanism of these active ingredients for better understanding the material basis and drug application of fructus psoraleae in Chinese medicine.

Donepezil attenuates vascular dementia in rats through increasing BDNF induced by reducing HDAC6 nuclear translocation

Vascular dementia (VD) is the second most common dementia disease after Alzheimer's diseases (AD) in the world. Donepezil is used to treat mild to moderate AD, and it has been shown to treat cognitive impairment and memory deficits caused by VD. However, the action mechanism of donepezil against VD has not been clarified. In this study, a bilateral common carotid artery occlusion (BCCAO) model was established in rats to simulate the pathology of VD. Two weeks after the surgery, the rats were administered donepezil (10 mg · kg^-1 · d^-1, ig) for 3 weeks, and then subjected to behavioral tests. We showed that donepezil treatment significantly improved the performance of BCCAO rats in Morris Water Mazes test and Step-down test. Furthermore, we showed that donepezil treatment significantly attenuated neurodegeneration and restored the synapse dendritic spines density in cortex and hippocampus. We revealed that donepezil treatment significantly increased BDNF expression in cortex and hippocampus. Interestingly, donepezil treatment significantly decreased nuclear translocation of HDAC6 and the binding between HDAC6 and BDNF promoter IV in cortex, but not in the hippocampus. The attenuated neurodegeneration by donepezil in cortex and hippocampus might due to the reduced ROS levels and increased phosphorylation of AMPK, whereas increased phosphorylation of AKT was only detected in cortex. In conclusion, our results demonstrate that donepezil attenuates neurodegeneration in cortex and hippocampus via increasing BDNF expression; the regulation of donepezil on HDAC6 occurred in cortex, but not in the hippocampus. This study further clarifies the pharmacological mechanism of donepezil, while also emphasizes the promising epigenetic regulation of HDAC6.

CZ-7, a new derivative of Claulansine F, promotes remyelination induced by cuprizone by enhancing myelin debris clearance

The mechanism of demyelinating diseases is controversial, while demyelination and remyeliantion disorder is the acknowledged etiology and therapeutic target. Untill now, there is no efficient therapy for these diseases. CZ-7, a new derivative of Claulansine F, which has been reported before, were investigated its pro-remyelination effect and its associated mechanism in cuprizone (CPZ)-induced demyelination model. In this study, male C57BL/6 mice were subjected to CPZ (300 mg/kg) through intragastric gavage and were orally administered CZ-7 (20 mg/kg) meanwhile. The results of weight monitoring and behavioral testing showed that CZ-7 can significantly improve behavior dysfunction in the demyelinating mice. Luxol-fast blue (LFB) staining, myelin basic protein (MBP) immunostaining, transmission electron microscopy (TEM) and QPCR results indicated the therapeutic effect of CZ-7 on CPZ mice model. Furthermore, degraded myelin basic protein (dMBP) immunofluorescent staining and oil red O staining showed that CZ-7 contributed to the clearance of degraded myelin debris. More microglia displayed phagocytic shape assembled in corpus callosum (CC) and there was an active process of phagocytosis in microglia after CZ-7 treatment. Immunofluorescent staining and QPCR analysis revealed the M2-polarized phenotype switch of microglia in the process of myelin debris removel, which demostrated the microenvironment improvement of CZ-7. Moreover, immunofluorescent staining of NG2 and O4 demonstated that more oligodendrocyte precursor cells (OPCs) existed in CC after CZ-7 treatment. In conclusion, our results demonstrated CZ-7 has a potential therapeutic effect for MS and other demyelinating diseases through enhancing myelin debris clearance to improve the microenvironment.

Possible mechanisms of lycopene amelioration of learning and memory impairment in rats with vascular dementia

Oxidative stress is involved in the pathogenesis of vascular dementia. Studies have shown that lycopene can significantly inhibit oxidative stress; therefore, we hypothesized that lycopene can reduce the level of oxidative stress in vascular dementia. A vascular dementia model was established by permanent bilateral ligation of common carotid arteries. The dosage groups were treated with lycopene (50, 100 and 200 mg/kg) every other day for 2 months. Rats without bilateral carotid artery ligation were prepared as a sham group. To test the ability of learning and memory, the Morris water maze was used to detect the average escape latency and the change of search strategy. Hematoxylin-eosin staining was used to observe changes of hippocampal neurons. The levels of oxidative stress factors, superoxide dismutase and malondialdehyde, were measured in the hippocampus by biochemical detection. The levels of reactive oxygen species in the hippocampus were observed by dihydroethidium staining. The distribution and expression of oxidative stress related protein, neuron-restrictive silencer factor, in hippocampal neurons were detected by immunofluorescence histochemistry and western blot assays. After 2 months of drug administration, (1) in the model group, the average escape latency was longer than that of the sham group, and the proportion of straight and tend tactics was lower than that of the sham group, and the hippocampal neurons were irregularly arranged and the cytoplasm was hyperchromatic. (2) The levels of reactive oxygen species and malondialdehyde in the hippocampus of the model group rats were increased, and the activity of superoxide dismutase was decreased. (3) Lycopene (50, 100 and 200 mg/kg) intervention improved the above changes, and the lycopene 100 mg/kg group showed the most significant improvement effect. (4) Neuron-restrictive silencer factor expression in the hippocampus was lower in the sham group and the lycopene 100 mg/kg group than in the model group. (5) The above data indicate that lycopene 100 mg/kg could protect against the learning-memory ability impairment of vascular dementia rats. The protective mechanism was achieved by inhibiting oxidative stress in the hippocampus. The experiment was approved by the Animal Ethics Committee of Fujian Medical University, China (approval No. 2014-025) in June 2014.

Vascular Cognitive Impairment: Information from Animal Models on the Pathogenic Mechanisms of Cognitive Deficits

Vascular cognitive impairment (VCI) is the second most common cause of cognitive deficit after Alzheimer's disease. Since VCI patients represent an important target population for prevention, an ongoing effort has been made to elucidate the pathogenesis of this disorder. In this review, we summarize the information from animal models on the molecular changes that occur in the brain during a cerebral vascular insult and ultimately lead to cognitive deficits in VCI. Animal models cannot effectively represent the complex clinical picture of VCI in humans. Nonetheless, they allow some understanding of the important molecular mechanisms leading to cognitive deficits. VCI may be caused by various mechanisms and metabolic pathways. The pathological mechanisms, in terms of cognitive deficits, may span from oxidative stress to vascular clearance of toxic waste products (such as amyloid beta) and from neuroinflammation to impaired function of microglia, astrocytes, pericytes, and endothelial cells. Impaired production of elements of the immune response, such as cytokines, and vascular factors, such as insulin-like growth factor 1 (IGF-1), may also affect cognitive functions. No single event could be seen as being the unique cause of cognitive deficits in VCI. These events are interconnected, and may produce cascade effects resulting in cognitive impairment.