Salidroside shows anticonvulsant and neuroprotective effects by activating the Nrf2-ARE pathway in a pentylenetetrazol-kindling epileptic model

The Keap1/Nrf2/ARE/HO-1 axis in epilepsy: Crosstalk between oxidative stress and neuroinflammation

Epilepsy is a complex neurological disorder characterized by recurrent seizures, which are driven by multifaceted pathophysiological mechanisms, including oxidative stress and neuroinflammation. Despite advancements in anti-seizure medications (ASMs), a significant proportion of patients remain resistant to treatment, highlighting the need for novel therapeutic strategies. This review focuses on the Kelch-like ECH-associated protein 1 (Keap1) / Nuclear factor erythroid 2-related factor 2 (Nrf2) / Antioxidant Response Element (ARE) / Heme Oxygenase-1 (HO-1) axis as a promising target for neuroprotection in epilepsy. We explored the intricate interactions between Keap1 and Nrf2 under homeostatic conditions and how oxidative stress disrupts this balance, triggering Nrf2 activation. This review details the subsequent process of Nrf2 nuclear translocation, its binding to AREs, and the induction of cytoprotective gene expression, which collectively orchestrate a robust cellular defense response. Special emphasis is placed on HO-1, a key effector of Nrf2-mediated neuroprotection, highlighting its enzymatic function and protective mechanisms, including antioxidant, anti-inflammatory, and anti-apoptotic effects. Additionally, the review examines HO-1's role in mitigating seizure-induced neuronal damage. However, challenges remain, including variability in therapeutic responses, gaps in long-term clinical validation, and the need for standardized protocols. Future research should focus on biomarkers for personalized treatment, advanced imaging, and genetic tools to explore the Keap1/Nrf2/ARE/HO-1 axis in greater depth. Future studies should focus on overcoming the challenges of translating preclinical findings into clinical applications and exploring the long-term effects of targeting this pathway in epilepsy treatment.

Neuroprotection in pentylenetetrazol kindling rat model: A synergistic approach with eugenol and photobiomodulation

Epilepsy is a complex neurological disorder characterized by recurrent seizures, significantly impacting patient health and quality of life. This study explores the neuroprotective effects of combining Eugenol (EUG), a natural bioactive compound administered at 100 mg/kg, with photobiomodulation (PBM), a non-invasive low-level laser therapy at 830 nm wavelength and 100 mW power, in a pentylenetetrazole (PTZ) kindling rat model of epilepsy. Fifty-nine adult male Wistar rats were assigned to five experimental groups: Control, PTZ (epilepsy model), PBM, EUG, and EUG + PBM. Seizure severity was assessed using a modified Racine scale following each PTZ injection. The study also evaluated cortical and hippocampal levels of brain-derived neurotrophic factor (BDNF), oxidative stress markers (MDA, NO, and GSH), activities of acetylcholinesterase (AChE) and Na + K + -ATPase, and monoamine neurotransmitters (DA, 5-HT, and NE). The results demonstrated that EUG and PBM, both individually and combined, significantly reduced seizure severity, mitigated oxidative stress, restored enzyme activities, and elevated BDNF levels. The combined treatment yielded superior neuroprotective effects compared to individual interventions, emphasizing its potential as a promising therapeutic strategy for epilepsy management.

Design and synthesis of novel cyclohexanecarboxamides with anticonvulsant effect by activating Nrf2-ARE pathway

This study investigated a series of novel cyclohexanecarboxamide derivatives 4a-e, 5a-e and 6a-e as anticonvulsant and neuroprotective agents. Compounds 4a-e, 5a-e, and 6a-e were synthesized starting from cyclohexanone and aniline derivatives and evaluated for their anticonvulsant effects using maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure models. The most potent compounds 4b, 5c, and 6d demonstrated 83.33 % protection in the scPTZ test, while compounds 5a and 6b showed 100 % protection in the MES test. Further quantitative evaluation showed that compound 6d was the most active derivative in scPTZ test (ED50 = 0.04 mmol/kg) and it was more potent than the two reference drugs phenobarbital and ethosuximide by 1.7 and 25.7-fold, respectively. Notably, all the compounds were free from neurotoxic side effects. Mechanistic studies indicated that the compounds 4b, 5c, and 6d exerted neuroprotective effects by modulating oxidative stress markers and activating the Nrf2/ARE pathway. Histopathological examination of brain of animals treated with compounds 4b, 5c, or 6d corroborated the neuroprotective properties. Additionally, molecular docking study and dynamic simulations were also carried out to study the mechanism of Nrf2 activation by the most active compound 6d. These results spotlight the potential of these derivatives as promising candidates for further development as anti-epileptic and neuroprotective agents.

The primary studies of epigallocatechin-3-gallate in improving brain injury induced by chronic high-altitude natural environment in rats by 7.0T high-field MR imaging

BACKGROUND

Epigallocatechin-3-gallate (EGCG) is one of the most abundant and important bioactive polyphenolic compounds in green tea. However, despite its potent antioxidant effects, its neuroprotective effects on chronic high altitude (HA)-induced nerve damage have not been reported. The purpose of this study is to use quantitative susceptibility mapping (QSM) with pathology to dynamically evaluate the status of brain damage and the effect of EGCG.

METHODS

A model of HA environments-induced brain injury was established of Sprague-Dawley (SD) rats in a natural plateau environment for 4 weeks, 8 weeks, 12 weeks and 20 weeks. Behavioral alterations were then observed and assessed with the open field test (OFT) and Morris water maze (MWM) test. The microglial activation, nissl staining and neural degeneration by Fluoro Jade B in the hippocampus of the rats were observed by immunohistochemistry. In the rats, serum erythropoietin (EPO), hippocampal inflammatory cytokines (interleukin-1β [IL-1β], interleukin-6 [IL-6] and tumor necrosis factor-α [TNF-α]), ferritin, oxidative stress (superoxide dismutase [SOD], glutathione peroxidase [GSH-Px], catalase [CAT] and malondialdehyde [MDA]) were detected using ELISA kits and biochemical methods. Iron accumulation was observed by QSM and colorimetry. Iron metabolisms (ceruloplasmin [Cp], transferrin [Tf], divalent metal transport1 [DMT1] and hepcidin [Hep]) were detected using qPCR. Neural ultrastructural changes were evaluated with electron microscope. Salidroside treatment was chosen as the positive control group in ELISA, biochemical detection and electron microscopy.

RESULTS

The susceptibility values in the left and right hippocampus, the hippocampal ferritin, serum and hippocampal iron content increased significantly after HA exposure. The expression of hippocampal Cp and Hep decreased and the expression of Tf increased. Nissl staining revealed that the neurons of hippocampal CA1 region of h-20w group were small and irregular, atrophied, and nuclear shrinkage. Tissue oxidative stress and inflammatory indicators (MDA, TNF-α, IL-1β, IL-6) increased while antioxidant enzymes (SOD, CAT, GSH-Px) decreased. EGCG attenuated HA environments-induced cognitive impairment, iron accumulation, microglial activation and neural degeneration. The effects of EGCG in reducing EPO and the metal chelating property with respect to iron were dose-dependent, with effects of EGCG (50 mg/kg) being similar to those of salidroside (50 mg/kg).

CONCLUSIONS

EGCG can act as a neuroprotective agent against chronic HA environments-mediated neural injuries. QSM provides a potential complementary imaging technique to detect the effect of treating HA diseases.

Salidroside: An Overview of Its Promising Potential and Diverse Applications

Salidroside, a phenolic compound isolated from various Rhodiola plants, is the principal active constituent of Traditional Chinese Medicine known for its adaptogenic properties. Due to the challenging environment of Rhodiola species, such as high altitude, high radiation, drought, and hypoxia, the source of salidroside is scarce. However, numerous studies have shown that salidroside has a range of biological activities, including cardiovascular and central nervous system activity, and anti-hypoxia, anti-inflammatory, and anti-aging activities. Although previous studies have partially summarized the pharmacological effects of salidroside, the overall pharmacological effects have not been analyzed. Hence, this review will systematically summarize the isolation, purification, synthesis, derivatization, pharmacological activity, pharmacokinetics, clinical application, and safety of salidroside. It is expected to provide new insights for the further research and pharmaceutical development of salidroside.

Anticonvulsant effect of glycitin in pentylenetetrazol induced male Wistar rat model by targeting oxidative stress and Nrf2/HO-1 signaling

Epilepsy, characterized by recurrent seizures, poses a significant health challenge globally. Despite the availability of anti-seizure medications, their adverse effects and inadequate efficacy in controlling seizures propel the exploration of alternative therapeutic measures. In hypothesis, glycitin is a phytoestrogenic compound found in soybeans and due to its estrogenic properties may have anti-epileptic and neuroprotective effects. This study investigates the potential anti-epileptic properties of glycitin in the context of pentylenetetrazol (PTZ) induced seizures in male Wistar rats. The rats were pretreated with varying doses of glycitin (5, 10, and 20 mg/kg) before PTZ (35 mg/kg) administration, and assessments included behavioral observations and histological evaluation via hematoxylin and eosin (H&E) staining. Additionally, oxidative stress markers, such as malondialdehyde (MDA), glutathione peroxidase (GPx), and superoxide dismutase (SOD) levels, were quantified to examine glycitin's impact on oxidative stress. Molecular analysis was conducted to assess the activation of the Nuclear factor erythroid 2-related factor (Nrf2)/Heme oxygenase 1 (HO-1) signaling pathway. Results indicated that glycitin pretreatment effectively mitigated PTZ-induced convulsive behaviors, supported by histological findings from H&E staining. Furthermore, glycitin administration led to significant alterations in MDA, GPx, and SOD levels, suggestive of its ability to modulate oxidative stress. Notably, glycitin treatment induced activation of the Nrf2/HO-1 signaling pathway. These findings underscore the potential of glycitin as an anticonvulsant agent, elucidating its mechanism of action through histological protection, modulation of oxidative stress markers, and activation of the Nrf2/HO-1 signaling pathway.

Research progress on the role of inflammatory mediators in the pathogenesis of epilepsy

Epilepsy is an abnormal neurologic disorder distinguished by the recurrent manifestation of seizures, and the precise underlying mechanisms for its development and progression remain uncertain. In recent years, the hypothesis that inflammatory mediators and corresponding pathways contribute to seizures has been supported by experimental results. The potential involvement of neuroinflammation in the development of epilepsy has garnered growing interest. This review centers attention on the involvement of inflammatory mediators in the emergence and progression of epilepsy within recent years, focusing on both clinical research and animal models, to enhance comprehension of the intricate interplay between brain inflammation and epileptogenesis.

Barbaloin Protects Pentylenetetrazol-Induced Cognitive Deficits in Rodents via Modulation of Neurotransmitters and Inhibition of Oxidative-Free-Radicals-Led Inflammation

BACKGROUND

Epilepsy is defined by an excessive level of activity in the neurons and coordinated bursts of electrical activity, resulting in the occurrence of seizure episodes. The precise cause of epileptogenesis remains uncertain; nevertheless, the etiology of epilepsy may involve neuroinflammation, oxidative stress, and malfunction of the neurotransmitter system.

OBJECTIVE

The goal of this investigation was to assess barbaloin's protective properties with respect to pentylenetetrazol (PTZ)-)-induced cognitive deficits in rats via antioxidative, anti-inflammatory, and neurotransmitter-modulating effects.

METHODS

Wistar rats were subjected to PTZ [40 mg/kg (i.p.)], which induced cognitive decline. Behavior assessment using a kindling score, open-field test (OFT), novel object recognition test (NORT), and assays for superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), malondialdehyde (MDA), acetylcholinesterase (AChE), caspase-3, nitric oxide (NO), interleukins-1β (IL-1β), tumor necrosis factor-α (TNF-α), IL-6, nuclear factor kappa-B (NF-κB), Bcl-2 and Bax, and neurotransmitter levels [GABA, DA, NE, and serotonin (5-HT)] were performed.

RESULTS

The treatment of rats with barbaloin resulted in behavior improvement and significant changes in the levels of GSH, SOD, CAT, MDA, AChE, NO, IL-6, IL-1β, TNF-α, NF-κB, caspase-3, Bcl-2, and Bax compared to the PTZ control group. Barbaloin treatment resulted in notable changes in neurotransmitter levels (GABA, NE, 5-HT, DA) compared to the PTZ group.

CONCLUSIONS

The ongoing study has gathered evidence indicating that the injection of barbaloin has resulted in significant improvements in cognitive performance in rats. This is achieved by inhibiting oxidative stress, enhancing the activity of natural antioxidant enzymes, reducing cytokine levels, and increasing the levels of neurotransmitters in the brain. These results were detected in comparison to a PTZ control and can be attributed to the potent anti-inflammatory and antioxidant capabilities of barbaloin, which could be linked to its neuroprotective properties. Barbaloin may potentially increase cognitive decline and boost neuronal survival by altering the expression of Bax, caspase-3, Bcl-2.

Phytotherapeutic options for the treatment of epilepsy: pharmacology, targets, and mechanism of action

Epilepsy is one of the most common, severe, chronic, potentially life-shortening neurological disorders, characterized by a persisting predisposition to generate seizures. It affects more than 60 million individuals globally, which is one of the major burdens in seizure-related mortality, comorbidities, disabilities, and cost. Different treatment options have been used for the management of epilepsy. More than 30 drugs have been approved by the US FDA against epilepsy. However, one-quarter of epileptic individuals still show resistance to the current medications. About 90% of individuals in low and middle-income countries do not have access to the current medication. In these countries, plant extracts have been used to treat various diseases, including epilepsy. These medicinal plants have high therapeutic value and contain valuable phytochemicals with diverse biomedical applications. Epilepsy is a multifactorial disease, and therefore, multitarget approaches such as plant extracts or extracted phytochemicals are needed, which can target multiple pathways. Numerous plant extracts and phytochemicals have been shown to treat epilepsy in various animal models by targeting various receptors, enzymes, and metabolic pathways. These extracts and phytochemicals could be used for the treatment of epilepsy in humans in the future; however, further research is needed to study the exact mechanism of action, toxicity, and dosage to reduce their side effects. In this narrative review, we comprehensively summarized the extracts of various plant species and purified phytochemicals isolated from plants, their targets and mechanism of action, and dosage used in various animal models against epilepsy.

Neuroprotective effect of salidroside on hippocampal neurons in diabetic mice via PI3K/Akt/GSK-3β signaling pathway

BACKGROUND

Diabetic encephalopathy is manifested by cognitive dysfunction. Salidroside, a nature compound isolated from Rhodiola rosea L, has the effects of anti-inflammatory and antioxidant, hypoglycemic and lipid-lowering, improving insulin resistance, inhibiting cell apoptosis, and protecting neurons. However, the mechanism by which salidroside alleviates neuronal degeneration and improves learning and memory impairment in diabetic mice remains unclear.

OBJECTIVE

To investigate the effects and mechanisms of salidroside on hippocampal neurons in streptozotocin-induced diabetic mice.

MATERIALS AND METHODS

C57BL/6 mice were randomly divided into 4 groups to receive either sham (control group (CON)), diabetes mellitus (diabetes group (DM)), diabetes mellitus + salidroside (salidroside group (DM + SAL)), and diabetes mellitus + salidroside + phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 (diabetes mellitus + salidroside + LY294002 group (DM + SAL + LY294002)). After 12 weeks of diabetes onset, the cognitive behaviors were tested using Morris water maze. The number of hippocampal neurons was detected by Nissl staining. The expressions of PI3K, p-PI3K, Akt, p-Akt, GSK-3β, p-GSK-3β, cleaved caspase-3, caspase-3, Bax, Bcl-2, MAP2, and SYN in the hippocampus were detected by Western blot. Moreover, the expression of MAP2 and SYN in the hippocampus was further confirmed by immunofluorescence staining.

RESULTS

Salidroside increased the time of diabetic mice in the platform quadrant and reduced the escape latency of diabetic mice. Salidroside also increased the expression of p-PI3K, p-Akt, p-GSK-3β, MAP2, SYN, Bcl-2, while suppressed the expression of cleaved caspase-3, caspase3, and Bax in the DM + SAL group compared with the DM group (P < 0.05). The Nissl staining showed that the number of hippocampus neurons in the DM + SAL group was increased with the intact, compact, and regular arrangement, compared with the DM groups (P < 0.05). Interestingly, the protective effects of salidroside on diabetic cognitive dysfunction, hippocampal morphological alterations, and protein expressions were abolished by inhibition of PI3K with LY294002.

CONCLUSIONS

Salidroside exerts neuroprotective properties in diabetic cognitive dysfunction partly via activating the PI3K/Akt/GSK-3β signaling pathway.

Antioxidant Therapy Reduces Oxidative Stress, Restores Na,K-ATPase Function and Induces Neuroprotection in Rodent Models of Seizure and Epilepsy: A Systematic Review and Meta-Analysis

Epilepsy is a neurological disorder characterized by epileptic seizures resulting from neuronal hyperexcitability, which may be related to failures in Na,K-ATPase activity and oxidative stress participation. We conducted this study to investigate the impact of antioxidant therapy on oxidative stress, Na,K-ATPase activity, seizure factors, and mortality in rodent seizure/epilepsy models induced by pentylenetetrazol (PTZ), pilocarpine (PILO), and kainic acid (KA). After screening 561 records in the MEDLINE, EMBASE, Web of Science, Science Direct, and Scopus databases, 22 were included in the systematic review following the PRISMA guidelines. The meta-analysis included 14 studies and showed that in epileptic animals there was an increase in the oxidizing agents nitric oxide (NO) and malondialdehyde (MDA), with a reduction in endogenous antioxidants reduced glutathione (GSH) and superoxide dismutase (SO). The Na,K-ATPase activity was reduced in all areas evaluated. Antioxidant therapy reversed all of these parameters altered by seizure or epilepsy induction. In addition, there was a percentage decrease in the number of seizures and mortality, and a meta-analysis showed a longer seizure latency in animals using antioxidant therapy. Thus, this study suggests that the use of antioxidants promotes neuroprotective effects and mitigates the effects of epilepsy. The protocol was registered in the Prospective Register of Systematic Reviews (PROSPERO) CRD42022356960.

Mechanisms of ferroptosis in Alzheimer's disease and therapeutic effects of natural plant products: A review

Neurodegenerative diseases, such as Alzheimer's disease (AD), are characterized by massive loss of specific neurons. It is a progressive disabling, severe and fatal complex disease. Due to its complex pathogenesis and limitations of clinical treatment strategies, it poses a serious medical challenge and medical burden worldwide. The pathogenesis of AD is not clear, and its potential biological mechanisms include aggregation of soluble amyloid to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFT), neuroinflammation, ferroptosis, oxidative stress and metal ion disorders. Among them, ferroptosis is a newly discovered programmed cell death induced by iron-dependent lipid peroxidation and reactive oxygen species. Recent studies have shown that ferroptosis is closely related to AD, but the mechanism remains unclear. It may be induced by iron metabolism, amino acid metabolism and lipid metabolism affecting the accumulation of iron ions. Some iron chelating agents (deferoxamine, deferiprone), chloroiodohydroxyquine and its derivatives, antioxidants (vitamin E, lipoic acid, selenium), chloroiodohydroxyquine and its derivatives Fer-1, tet, etc. have been shown in animal studies to be effective in AD and exert neuroprotective effects. This review summarizes the mechanism of ferroptosis in AD and the regulation of natural plant products on ferroptosis in AD, in order to provide reference information for future research on the development of ferroptosis inhibitors.

Mechanism of salidroside in the treatment of chronic myeloid leukemia based on the network pharmacology and molecular docking

BACKGROUND

Salidroside is a phenolic natural product, which is a kind of Rhodiola rosea. It has been confirmed that it has inhibitory effects on chronic myeloid leukemia, but the specific performance of its molecular effects is still unclear.

OBJECTIVE

To systematically study the pharmacological mechanism of salidroside on chronic myeloid leukemia by means of network pharmacology.

METHODS

First, the possible target genes of salidroside were predicted through the Traditional Chinese Medicine Pharmacology Database and Analysis Platform, the target gene names were converted into standardized gene names using the Uniprot website. At the same time, the related target genes of chronic myeloid leukemia were collected from GeneCards and DisGenet; Collect summary data and screen for commonly targeted genes. Then, the above-mentioned intersected genes were imported into the String website to construct the protein-protein interaction (PPI) network, and the Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were further analyzed. To investigate the overall pharmacological effects of salidroside on chronic myeloid leukemia, we constructed a drug component-target gene-disease (CTD) network. Finally, molecular docking was performed to verify the possible binding conformation between salidroside and the candidate target.

RESULTS

A total of 126 salidroside target genes were retrieved, and 106 of them had interactions with chronic myeloid leukemia. The pharmacological effects of salidroside on chronic myeloid leukemia are related to some important oncogenes and signaling pathways. Molecular docking studies confirmed that the main role of salidroside binding to the target genes is hydrogen bonding.

CONCLUSIONS

We revealed the potential mechanism of action of salidroside against chronic myeloid leukemia, verified by network pharmacology combined with molecular docking. However, salidroside is a promising drug for the prevention and treatment of chronic myeloid leukemia, and further research is needed to prove it.

A facile and efficient synthesis approach of salidroside esters by whole-cell biocatalysts in organic solvents

Salidroside, the main bioactive compound isolated from the plant source of Rhodiola rosea L, possesses broad-spectrum pharmacological activities, but suffers from the low cell membranes permeability and alimentary absorption due to its high polarity. Therefore, a whole-cell catalytic strategy for the synthesis of salidroside esters was explored to improve its lipophilicity. The results showed that Aspergillus oryzae demonstrated the highest biocatalytic activity among the microbial strains tested. For the synthesis of salidroside caprylate, the optimum conditions of reaction medium, Aspergillus oryzae amount, molar ratio of vinyl caprylate to salidroside and reaction temperature were acetone, 30 mg/ml, 10°C and 40°C, respectively. Under these conditions, the initial reaction rate was 15.36 mM/h, and substrate conversion and regioselectivity all reached 99%. Moreover, the results indicated that although various 6'-monoesters derivatives of salidroside were exclusively obtained with excellent conversions (96%-99%), the reaction rate varied greatly with different chain-length acyl donors. This study details an efficient and cost-effective biocatalytic approach for the synthesis of salidroside esters by using Aspergillus oryzae as a catalyst for the first time. Considering the whole cell catalytic efficiency and operational stability, this strategy may provide a new opportunity to develop green industrial processes production for ester derivatives of salidroside and its analogues.

Rhodiola pre-conditioning reduces exhaustive exercise-induced myocardial injury of insulin resistant mice

Myocardial injury reduction and recovery under acute cardiac stress are adversely impacted by insulin resistance (IR). We previously demonstrated that Rhodiola improved cardiac anti-stress capacity in mice. Thus, this study focuses on the preventive efficacy of Rhodiola on exhaustive exercise (EE)-induced myocardial injury of IR mice. An 8-week high-fat diet (HFD) model of IR mice was established. Rhodiola was administrated by garaging. After the 8-week intervention, half of the mice performed EE to simulate acute cardiac stress, and determine myocardial injury; The remaining mice were sacrificed following fasting to assess metabolic disorder. We found myocardial injury induced by EE in IR mice was worse and was alleviated by Rhodiola pre-conditioning. Further, the nuclear factor erythroid 2-related factor 2 (Nrf2)-related antioxidant system was impaired by HFD, while mitochondrial dynamic fusion and fission were activated by HFD as a physiological protective compensation. The Rhodiola administration rescued Nrf2 impairment and further facilitated mitochondrial fusion and fission. All these results indicate that Rhodiola is a potential treatment for the prevention of cardiac events in type 2 diabetes mellitus and metabolic syndrome patients, and the Nrf2-related antioxidant activity and mitochondrial dynamics are the proposed mechanisms.

Aqueous extract of Parkia biglobosa (Jacq.) R. Br. (Fabaceae) exerts antiepileptogenic, anti-amnesic, and anxiolytic-like effects in mice via mechanisms involving antioxidant and anti-inflammatory pathways

Parkia biglobosa (Jacq.) R. Br. (Fabaceae) is a widely distributed tree, used in traditional medicine to treat amebiasis, hookworm infection, ascariasis, asthma, sterility, dental pain, headaches, cardiac disorders, and epilepsy. To date, no study on the effect of an aqueous extract of P. biglobosa on epileptogenesis and associated neuropsychiatric disorders has been undertaken. Therefore, this study aimed to investigate antiepileptogenic-, antiamnesic-, and anxiolytic-like effects of an aqueous extract of P. biglobosa using pentylenetetrazole (PTZ)-induced kindling in mice. Animals were divided into six groups of eight mice each. Thus, a PTZ group received distilled water (10 ml/kg, per os), a positive control group received sodium valproate (300 mg/kg, p.o.), and three test groups received the aqueous extract of P. biglobosa (80, 160, and 320 mg/kg, p.o.).In addition, a control group of eight mice receiving distilled water (10 ml/kg, p.o.) was formed. The treatments were administered to mice, 60 min before administration of PTZ (20 mg/kg, i.p.). These co-administrations were performed once daily, for 22 days. The number and duration of seizures (stages 1, 2, 3, and 4 of seizures) exhibited by each mouse were assessed for 30 min during the treatment period. Twenty-four hours following the last administration of the treatments and PTZ, novel object recognition and T-maze tests were performed to assess working memory impairment in mice, while the open field test was performed to assess anxiety-like behavior. After these tests, the animals were sacrificed, and the hippocampi were collected for biochemical and histological analysis. During the period of PTZ-kindling, the extract at all doses completely (p < 0.001) protected all mice against stages 3 and 4 of seizures when compared to sodium valproate, a standard antiepileptic drug. The extract also significantly (p < 0.001) attenuated working memory impairment and anxiety-like behavior. In post-mortem brain analyses, the extract significantly (p < 0.001) increased γ-aminobutyric acid (GABA) level and reduced oxidative stress and inflammation. Histological analysis showed that the aqueous extract attenuated neuronal degeneration/necrosis in the hippocampus. These results suggest that the extract is endowed with antiepileptogenic-, anti-amnesic-, and anxiolytic-like effects. These effects seem to be mediated in part by GABAergic, antioxidant, and anti-inflammatory mechanisms. These results suggest the merit of further studies to isolate the bioactive molecules responsible for these potentially therapeutically relevant effects of the extract.

Salidroside attenuates neuronal ferroptosis by activating the Nrf2/HO1 signaling pathway in Aβ1-42-induced Alzheimer's disease mice and glutamate-injured HT22 cells

Background

Alzheimer’s disease (AD) is a neurodegenerative disease. Ferroptosis plays a critical role in neurodegenerative diseases. Nuclear factor E2-related factor 2 (Nrf2) is considered an important factor in ferroptosis. Studies have demonstrated that salidroside has a potential therapeutic effect on AD. The intrinsic effect of salidroside on ferroptosis is unclear. The purpose of this study was to investigate the protective effects and pharmacological mechanisms of salidroside on alleviating neuronal ferroptosis in Aβ₁₋₄₂-induced AD mice and glutamate-injured HT22 cells.

Methods

HT22 cells were injured by glutamate (Glu), HT22 cells transfected with siRNA Nrf2, and Aβ₁₋₄₂-induced WT and Nrf2^−/−AD mice were treated with salidroside. The mitochondria ultrastructure, intracellular Fe²⁺, reactive oxygen species, mitochondrial membrane potential, and lipid peroxidation of HT22 cells were detected. Malondialdehyde, reduced glutathione, oxidized glutathione disulfide, and superoxide dismutase were measured. The novel object recognition test, Y-maze, and open field test were used to investigate the protective effects of salidroside on Aβ₁₋₄₂-induced WT and Nrf2^−/−AD mice. The protein expressions of PTGS2, GPX4, Nrf2, and HO1 in the hippocampus were investigated by Western blot.

Results

Salidroside increased the cell viability and the level of MMP of Glu-injured HT22 cells, reduced the level of lipid peroxidation and ROS, and increased GPX4 and SLC7A11 protein expressions. These changes were not observed in siRNA Nrf2 transfected HT22 cells. Salidroside improved the ultrastructural changes in mitochondria of HT22 cells and Aβ₁₋₄₂-induced AD mice, but not in Aβ₁₋₄₂-induced Nrf2^−/−AD mice. Salidroside increased protein expression levels of GPX4, HO1, and NQO1 and decreased protein expression of PTGS2 in Aβ₁₋₄₂-induced AD mice but not in Aβ₁₋₄₂-induced Nrf2^−/−AD mice.

Conclusions

Salidroside plays a neuroprotective role by inhibiting neuronal ferroptosis in Aβ₁₋₄₂-induced AD mice and Glu-injured HT22 cells, and its mechanism is related to activation of the Nrf2/HO1 signaling pathway.

Graphical Abstract

Anti-kindling effect of Ginkgo biloba leaf extract and L-carnitine in the pentylenetetrazol model of epilepsy

Epilepsy is one of the most common serious brain disorders, affecting about 1% of the population all over the world. Ginkgo biloba extract (GbE) and L-carnitine (LC) reportedly possess the antioxidative activity and neuroprotective potential. In this report, we investigated the possible protective and therapeutic effects of GbE and LC against pentylenetetrazol (PTZ)-induced epileptic seizures in rat hippocampus and hypothalamus. Adult male albino rats were equally divided into eight groups: control, GbE (100 mg/kg), LC (300 mg/kg), PTZ (40 mg/kg), protective groups (GbE + PTZ and LC + PTZ), and therapeutic groups (PTZ + GbE and PTZ + LC). The oxidative stress, antioxidant, and neurochemical parameters, viz., malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), acetylcholine esterase (AchE), dopamine (DA), norepinephrine (NE), and serotonin (5-HT), in the hippocampal and hypothalamic regions have been evaluated. PTZ injection leads to an increase in the seizure score, the levels of MDA and NO, and to a decrease in the activity of GSH, SOD, CAT, and GPx. Besides, monoamine neurotransmitters, DA, NE, and 5-HT, were depleted in PTZ-kindled rats. Furthermore, PTZ administration caused a significant elevation in the activity of AchE. Hippocampal and hypothalamic sections from PTZ-treated animals were characterized by severe histopathological alterations and, intensely, increased the ezrin immunolabeled astrocytes. Pre- and post-treatment of PTZ rats with GbE and LC suppressed the kindling acquisition process and remarkably alleviated all the aforementioned PTZ-induced effects. GbE and LC have potent protective and therapeutic effects against PTZ-induced kindling seizures via the amelioration of oxidative/antioxidative imbalance, neuromodulatory, and antiepileptic actions.

Salidroside alleviates cadmium-induced toxicity in mice by restoring the notch/HES-1 and RIP1-driven inflammatory signaling axis

OBJECTIVE

Salidroside (SAL) is a marker glycoside of Rhodiola rosea with significant antioxidant, anti-inflammatory, and other health benefits. In this study, we determined its neuroprotective effects against Cd-induced toxicity in cultured cells and mice.

MATERIALS AND METHODS

GL261 cell and Cd-intoxicated mouse model were used. ICP-MS and MWM were performed to measure Cd content and Cd-induced cognitive impairment in mice, respectively.

RESULTS

SAL attenuated Cd toxicity in GL261 cells as well as protected mice from substantial organic damage and cognitive deficits. SAL treatment alleviated Cd-induced oxidative stress, glial cell activation, and elevation of pro-inflammatory factors including TNF-α, IL-1β, and IL-6. Cd-induced cognitive deficits observed in the Morris water maze in mice were rescued by SAL. At the mechanistic level, SAL maintained the activity of antioxidant enzymes such as SOD and GSH-Px in the serum and brain, and scavenged the peroxidation product MDA, thereby restoring redox homeostasis in vivo, attenuating neuronal damage, and ultimately antagonized Cd-induced toxicity. Furthermore, Cd activated the RIP1-driven inflammatory signaling pathway and Notch/HES-1 signaling axis in the brain, leading to inflammation and neuronal loss, which could be attenuated by SAL.

CONCLUSION

SAL is a natural product with good anti-Cd effects, indicating that Rhodiola rosea is promising plant that is worthy of cultivation for health and economic benefits.

Tianxiangdan Improves Coronary Microvascular Dysfunction in Rats by Inhibiting Microvascular Inflammation via Nrf2 Activation

Background

Tianxiangdan (TXD) is used in traditional Chinese medicine because of its therapeutic and preventive effects in the treatment of coronary heart disease. However, the underlying mechanism of TXD in coronary microvascular disease (CMD) remains unclear.

Methods

A rat model of CMD was developed to study the mechanism of TXD activity. Sodium laurate was injected into the left ventricle of Sprague–Dawley rats to induce CMD. The rats were divided into six groups: a sham-operated (sham) group, an untreated CMD group, a low-dose TXD group (0.81 g·kg⁻¹·d⁻¹), a mid-dose TXD (TXD-M) group (1.62 g·kg⁻¹·d⁻¹), a high-dose TXD (TXD-H) group (3.24 g·kg⁻¹·d⁻¹), and a nicorandil (NCR) group (1.35 mg·kg⁻¹·d⁻¹). The effect of TXD on rats with CMD was observed after four weeks, and the mechanism of TXD in lipopolysaccharide (LPS)-induced cardiac microvascular endothelial cells (CMECs) was explored through treatment with 50 μg/mL TXD.

Results

Compared with the rats in the untreated CMD group, rats in the TXD-M and TXD-H groups showed higher left ventricular ejection fraction values, improved pathological structures, decreased expressions of interleukin (IL)-1β, tumor necrosis factor-alpha (TNF-α), phosphorylated nuclear factor-κB inhibitor α (IκBα) and phosphorylated p65, and increased expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (P < 0.05). These effects were more pronounced in the TXD-H group than in the TXD-M group. In vitro experiments showed that TXD treatment increased the viability of LPS-induced CMECs and decreased the expression of IL-1β, TNF-α, phosphorylated IκBα, and phosphorylated p65 (P < 0.05). However, the effects of TXD on CMECs were markedly reversed upon treatment with ML385 (Nrf2 inhibitor).

Conclusion

The results showed that TXD exerts a protective effect on rats with CMD and related inflammatory injuries, and its anti-inflammatory mechanism is related to the activation of Nrf2 signalling.

Genistein protects epilepsy-induced brain injury through regulating the JAK2/STAT3 and Keap1/Nrf2 signaling pathways in the developing rats

BACKGROUND

Epilepsy is a common chronic neurological disease. Recurrent seizures can cause irreversible brain damage. This study aimed to explore the regulation of Genistein on JAK2/STAT3 and Keap1/Nrf2 signaling pathway and the protective effects on brain injury after epilepsy.

METHODS

Pentylenetetrazole (PTZ) was used to induce epilepsy in developing rats and Genistein was used for pretreatment of epilepsy. The seizure latency, grade scores and duration of the first generalized tonic-clonic seizure (GTCs) were recorded. Hippocampus tissue was sampled at 24 h post-epilepsy. Immunofluorescence staining was used to observe mature neurons, activated microglia and astrocytes in the hippocampal CA1 region. Western blot and qRT-PCR were used to determine the protein and mRNA levels of JAK2, STAT3, TNF-α, IL-1β, Keap1, Nrf2, HO-1, NQO1, caspase3, Bax and Bcl2 in the hippocampus.

RESULTS

Immunofluorescence showed that the number of neurons significantly decreased, and activated microglia and astrocytes significantly increased after epilepsy; Western blot and q-PCR showed that the expressions of JAK2, STAT3, TNF-α, IL-1β, Keap1, caspase3 and Bax significantly increased, while Nrf2, HO-1, NQO1 and Bcl-2 were significantly reduced after epilepsy. These effects were reversed by Genistein treatment. Moreover, Genistein was found to prolong seizure latency and reduce seizure intensity score and duration of generalized tonic-clonic seizures(GTCs) CONCLUSIONS: Genistein can activate the Keap1/Nrf2 antioxidant stress pathway and attenuate the activation of microglia and astrocytes. Genistein also inhibits the JAK2-STAT3 inflammation pathway and expression of apoptotic proteins, and increases the number of surviving neurons, thus having a protective effect on epilepsy-induced brain damage.