Arbutin attenuates monosodium L-glutamate induced neurotoxicity and cognitive dysfunction in rats

Cognitive Rehabilitation For Early-Stage Dementia: A Review

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In the primary phases of Alzheimer's disease (AD) and vascular dementia, memory impairments and cognitive abnormalities are common. Because of the rising prevalence of dementia among the elderly, it is critical to promote healthy habits that can delay the onset of cognitive decline. Cognitive training (CT) and cognitive rehabilitation (CR) are particular treatments aimed to resolve memory and further areas of cognitive working in order to overcome these challenges. These are some of the different kinds of non-pharmacological treatments like reality orientation and skills training programs that can be used to deal with the cognitive and non-cognitive repercussions. The purpose of this review is to assess the efficacy and influence of cognitive training and cognitive rehabilitation in patients who are in their early phases of Alzheimer's disease or vascular dementia. These interventions are geared toward improving the patients' memory, in addition to other aspects of their cognitive functioning.

Toxicological profiling and diuretic potential of arbutin via aldosterone synthase gene inhibition

AIMS

Arbutin (ARB), a natural polyphenol isolated from the bearberry plant Arctostaphylos uva-ursi, has been studied for its diverse pharmacological activities including anti-diabetic, cardioprotective and anti-inflammatory effects. This study aimed to evaluate arbutin's diuretic activity, focusing on its impact on aldosterone synthase gene expression and its toxicity profile.

MATERIAL AND METHODS

Acute toxicity was assessed using single doses ranging from 500 to 9000 mg/kg and sub-acute toxicity with doses of 375 and 750 mg/kg over 14 days. To evaluate acute diuretic activity, ARB was administered in three doses (25, 50 and 75 mg/kg i.p) alongside standard groups, furosemide (FUR) 10 mg/kg i.p and Spironolactone (SPIR) 25 mg/kg i.p. In sub-acute diuretic study, treatment was administered for seven days, followed by blood collection and adrenal dissection for gene expression analysis.

KEY FINDINGS

Acute toxicity studies revealed that ARB is well-tolerated up to 7000 mg/kg with no significant changes in organ and body weight. However, sub-acute studies showed minor changes in leukocyte count, alkaline phosphatase (ALP), alanine aminotransferase (ALT) and triglycerides (TGs) at high doses while histopathological evaluations revealed no severe organ damage. The diuretic index and electrolyte analysis confirmed the potential of ARB as diuretic and saluretic with reduced risk of hyperuricemia and hyperkalemia. Gene expression studies showed non-selective downregulation of aldosterone synthase gene (CYP11B2) and 11β-hydroxylase (CYP11B1). While the effects on 17α-hydroxylase (CYP17A1) were less pronounced than SPIR, indicating fewer possible anti-androgenic effects.

SIGNIFICANCE

Our findings suggest that ARB is a promising diuretic agent with a favorable safety profile.

Elucidating the neuroprotective potential of arbutin in 3-NPA induced HD-like pathology: Insights from in silico, in vitro, and in vivo models

Huntington's disease (HD) is an inherited, hyperkinetic condition manifested by a triad of motor abnormalities, progressive cognitive impairment, and psychiatric disturbances. Oxidative stress has been implicated among other cellular processes in the pathogenesis of HD. Arbutin, a hydroquinone antioxidant, is reportedly neuroprotective in several animal models of neurodegenerative diseases. Hence, this research aimed to investigate the neuroprotective effect of arbutin against HD using in silico, in vitro, and in vivo experimental approaches. Schrodinger software was used for the in-silico studies, while SH-SY5Y cells were used for in-vitro studies. In the in vivo studies, adult Wistar rats were divided into five groups and 3-nitro propionic acid (3-NPA) (10 mg/kg/day,i.p) alone, and with arbutin (50 and 100 mg/kg/day,i.p.) was administered for 21 days. The body weight and behavioral parameters, including locomotor activity and motor coordination, were assessed on the 1st, 7th, 14th & 21st days. On the 22nd day, animals were sacrificed; the striatum was harvested for biochemical, neurochemical, and histopathological assessment. In silico, results indicated that arbutin showed a good binding affinity for target proteins like Akt and Nrf2. Further, arbutin prevented cell death and oxidative stress in SH-SY5Y cells induced by 3-NPA. In addition, arbutin ameliorated the 3-NPA induced motor impairments, purine nucleoside imbalances (adenosine levels and its metabolites hypoxanthine, xanthine, adenine), oxidative stress, and histological alterations in the experimental animals. In conclusion, the present findings indicate that arbutin could be used as an adjuvant for the management of Huntington's disease.

Protective Role of Electroacupuncture Against Cognitive Impairment in Neurological Diseases

Many neurological diseases can lead to cognitive impairment in patients, which includes dementia and mild cognitive impairment and thus create a heavy burden both to their families and public health. Due to the limited effectiveness of medications in treating cognitive impairment, it is imperative to develop alternative treatments. Electroacupuncture (EA), a required method for Traditional Chinese Medicine, has the potential treatment of cognitive impairment. However, the molecular mechanisms involved have not been fully elucidated. Considering the current research status, preclinical literature published within the ten years until October 2022 was systematically searched through PubMed, Web of Science, MEDLINE, Ovid, and Embase. By reading the titles and abstracts, a total of 56 studies were initially included. It is concluded that EA can effectively ameliorate cognitive impairment in preclinical research of neurological diseases and induce potentially beneficial changes in molecular pathways, including Alzheimer's disease, vascular cognitive impairment, chronic pain, and Parkinson's disease. Moreover, EA exerts beneficial effects through the same or diverse mechanisms for different disease types, including but not limited to neuroinflammation, neuronal apoptosis, neurogenesis, synaptic plasticity, and autophagy. However, these findings raise further questions that need to be elucidated. Overall, EA therapy for cognitive impairment is an area with great promise, even though more research regarding its detailed mechanisms is warranted.

Efficacy of repetitive transcranial magnetic stimulation in preventing postoperative delirium in elderly patients undergoing major abdominal surgery: A randomized controlled trial

BACKGROUND

Postoperative delirium (POD) is a serious complication in elderly patients after major surgery, associated with high morbidity and mortality. Treatment and prevention methods are limited. Repetitive transcranial magnetic stimulation (rTMS) shows potential in enhancing cognitive function and improving consciousness.

OBJECTIVE

To evaluate whether early postoperative rTMS has a protective effect against POD and to explore its potential mechanisms.

METHODS

Patients aged 60 years or older, scheduled for major abdominal surgery, were randomly assigned to receive rTMS at 100 % RMT, 10 Hz, with 2000 pulses targeting the DLPFC after extubation in PACU, either as active rTMS(n = 61) or sham rTMS (n = 61). The primary outcome was the incidence of POD during the first 3 postoperative days.

RESULTS

In the modified intention-to-treat analysis of 122 patients (mean [SD] age, 70.2 [4.1] years; 53.3 % women), POD incidence was lower in the rTMS group (11.5 %) compared to the sham rTMS group (29.5 %) (relative risk, .39; 95 % CI, .18 to .86; P = .01). rTMS patients had higher BDNF (8.47 [2.68] vs. 5.76 [1.42] ng/mL; P < .001) and lower NfL (.05 [.04] vs. .06 [.04] ng/mL; P = .02) levels. Mediation analysis suggests that rTMS may reduce POD by increasing brain-derived neurotrophic factor (z = -3.72, P < .001) rather than decreasing neurofilament light (z = 1.92, P = .06).

CONCLUSIONS

Immediate postoperative rTMS can reduce the incidence of POD in elderly patients undergoing major abdominal surgery, probably by upregulating brain-derived neurotrophic factor levels.

Natural Products and Their Neuroprotective Effects in Degenerative Brain Diseases: A Comprehensive Review

As the global population ages, the incidence of neurodegenerative diseases such as Alzheimer's and Parkinson's is rapidly rising. These diseases present a significant public health challenge, as they severely impair cognitive and motor functions, ultimately leading to a substantial reduction in quality of life and placing a heavy burden on healthcare systems worldwide. Although several therapeutic agents have been developed to manage the symptoms of these diseases, their effectiveness is often limited, and there remains an urgent need for preventive strategies. Growing evidence indicates that bioactive compounds from natural products possess neuroprotective properties through antioxidant and anti-inflammatory effects, modulating key pathways such as phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) and brain-derived neurotrophic factor-tropomyosin receptor kinase B-cAMP response element-binding protein (BDNF-TrkB-CREB), which are crucial for neuronal survival. These compounds may also reduce amyloid-beta and tau pathology, as well as enhance cholinergic neurotransmission by inhibiting acetylcholinesterase activity. By targeting oxidative stress, neuroinflammation, and neurodegeneration, natural products offer a promising approach for both prevention and treatment. These findings suggest that natural products may be promising for preventing and treating neurodegenerative diseases. This review aims to explore the pathogenesis of neurodegenerative diseases, the limitations of current therapies, and the potential role of natural products as therapeutic agents.

Targeting JAK2/STAT3, NLRP3/Caspase-1, and PK2/PKR2 Pathways with Arbutin Ameliorates Lead Acetate-Induced Testicular Injury in Rats

The reproductive system of males is adversely impacted by lead (Pb), a toxic heavy metal. The present study examined arbutin, a promising hydroquinone glycoside, for its potential ameliorative impact against Pb-induced testicular impairment in rats. The testicular injury was induced by the intraperitoneal administration of Pb acetate (20 mg/kg/day) for 10 consecutive days. Thirty-six rats were divided into six experimental groups (n = 6 per group): control, control treated with oral arbutin (250 mg/kg), control treated with intraperitoneal arbutin (75 mg/kg), untreated Pb, Pb treated with oral arbutin, and Pb treated with intraperitoneal arbutin. The treatments were administered daily for 10 days. Arbutin was administered by the oral and intraperitoneal routes to compare the efficacy of both routes in mitigating Pb acetate-induced testicular dysfunction. The current data revealed that both oral and intraperitoneal administration of arbutin significantly enhanced serum testosterone and sperm count/motility, indicating the amelioration of testicular dysfunction. In tandem, both routes lowered testicular histopathological aberrations and Johnsen's damage scores. These favorable outcomes were driven by dampening testicular oxidative stress, evidenced by lowered lipid peroxidation and increased glutathione and catalase antioxidants. Moreover, arbutin lowered testicular p-JAK2 and p-STAT3 levels, confirming the inhibition of the JAK2/STAT3 pro-inflammatory pathway. In tandem, arbutin suppressed the testicular NLRP3/caspase-1/NF-B axis and augmented the cytoprotective PK2/PKR2 pathway. Notably, intraperitoneal arbutin at a lower dose prompted a more pronounced mitigation of Pb-induced testicular dysfunction compared to oral administration. In conclusion, arbutin ameliorates Pb-evoked testicular damage by stimulating testicular antioxidants and the PK2/PKR2 pathway and inhibiting the JAK2/STAT3 and NLRP3/caspase-1 pro-inflammatory pathways. Hence, arbutin may be used as an adjunct agent for mitigating Pb-induced testicular impairment.

Efficacy of acupuncture combined with traditional Chinese herbal for primary epilepsy patients with cognitive impairment: A protocol for systematic review and meta-analysis

BACKGROUND

Epilepsy is a common and serious chronic neurological disorder, and some patients suffer from cognitive dysfunction. We aim to assess the efficacy and safety of acupuncture combined with traditional Chinese herbal for primary epilepsy patients with cognitive impairment.

METHODS

To search the randomized control trials (RCTs) published before April 20, 2023 from PubMed, Embase, Cochrane Library, Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Web of science, and Wanfang Database. The risk of bias within each individual trial was evaluated using the Cochrane Collaboration tool. RevMan5.3 software was used for statistical analysis. The odds ratio (OR) or weighted mean difference (WMD) with a 95% confidence interval (CI) was calculated for each RCT before data pooling.

RESULTS

The primary outcomes involve changes in cognitive function and behavioral disturbances. The secondary outcomes focused on quality of life and adverse effects.

CONCLUSION

The results of this review are expected to provide new guidelines for the treatment of primary epilepsy patients with cognitive impairment.

TRIAL REGISTRATION

This systematic review protocol was registered at the International Prospective Register of Systematic Reviews (PROSPERO) (Registration number: CRD42023415355).

Experimental evidence of the neurotoxic effect of monosodium glutamate in adult female Sprague Dawley rats: The potential protective role of Zingiber officinale Rosc. rhizomes

Strategies to prevent the health abnormalities associated with the extensive use of MSG (monosodium glutamate) as a flavoring booster are badly needed. The current study was conducted to investigate oxidative stress, inflammation, and abnormal lipid profile as the main risk factors of neurotoxicity in MSG-exposed female albino rats. Besides, the effect of concurrent consumption of Zingiber officinale rhizomes powder was studied at low doses. Twenty rats (total) were split into 4 separate groups. The 1st group was a negative control group (without any treatment), while the others received 6 mg MSG/kg. The 2nd group was left untreated, whereas the 3rd and 4th groups were given a regular laboratory diet that included ginger rhizome powder supplements (GRP, 0.5 & 1%, respectively) for six weeks. In brain tissue homogenates, exposure to MSG caused a significant depletion of gamma-aminobutyric acid (GABA) and total protein levels, while triglycerides and cholesterol contents were significantly elevated. Moreover, a noteworthy upsurge in oxidative load and inflammation markers was also noticed associated with a marked reduction of antioxidant levels, which histopathological staining verified further. The rat diet formulated with GRP, with a dose-dependent effect, resulted in increased GABA and total protein contents and attenuated inflammation, oxidative stress, abnormal lipid profile, and marked histological changes in cerebral cortical neurons of MSG-administered animals. Therefore, this study reveals that GRP shields rats against the neurotoxicity that MSG causes. The anti-inflammatory as well as antioxidant, and lipid-normalizing properties of rhizomes of ginger may be accountable for their observed neuroprotective action.

A systematic review of the neuropathology and memory decline induced by monosodium glutamate in the Alzheimer's disease-like animal model

This systematic review analyzes monosodium glutamate (MSG) in the Alzheimer's disease-like condition to enhance translational research. Our review seeks to understand how MSG affects the brain and causes degenerative disorders. Due to significant preclinical data linking glutamate toxicity to Alzheimer's disease and the lack of a comprehensive review or meta-analysis, we initiated a study on MSG's potential link. We searched PubMed, ScienceDirect, ProQuest, DOAJ, and Scopus for animal research and English language papers without time constraints. This study used the PRISMA-P framework and PICO technique to collect population, intervention or exposure, comparison, and result data. It was registered in PROSPERO as CRD42022371502. MSG affected mice's exploratory behaviors and short-term working memory. The brain, hippocampus, and cerebellar tissue demonstrated neuronal injury-related histological and histomorphometric changes. A total of 70% of MSG-treated mice had poor nesting behavior. The treated mice also had more hyperphosphorylated tau protein in their cortical and hippocampus neurons. Glutamate and glutamine levels in the brain increased with MSG, and dose-dependent mixed horizontal locomotor, grooming, and anxiety responses reduced. MSG treatment significantly decreased phospho-CREB protein levels, supporting the idea that neurons were harmed, despite the increased CREB mRNA expression. High MSG doses drastically lower brain tissue and serum serotonin levels. In conclusion, MSG showed AD-like pathology, neuronal atrophy, and short-term memory impairment. Further research with a longer time span and deeper behavioral characterization is needed. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier [CRD42022371502].

Influence of glutamatergic and GABAergic neurotransmission on obstructive sleep apnea

Glutamate and γ-aminobutyric acid (GABA) are the two main neurotransmitters in the human brain. The balance between their excitatory and inhibitory functions is crucial for maintaining the brain's physiological functions. Disturbance of glutamatergic or GABAergic neurotransmission leads to serious health problems including neurodegeneration, affective and sleep disorders. Both GABA and glutamate are involved in the control of the sleep-wake cycle. The disturbances in their function may cause sleep and sleep-related disorders. Obstructive sleep apnea (OSA) is the most common sleep respiratory disorder and is characterized by repetitive collapse of the upper airway resulting in intermittent hypoxia and sleep fragmentation. The complex pathophysiology of OSA is the basis of the development of numerous comorbid diseases. There is emerging evidence that GABA and glutamate disturbances may be involved in the pathogenesis of OSA, as well as its comorbidities. Additionally, the GABA/glutamate targeted pharmacotherapy may also influence the course of OSA, which is important in the implementation of wildly used drugs including benzodiazepines, anesthetics, and gabapentinoids. In this review, we summarize current knowledge on the influence of disturbances in glutamatergic and GABAergic neurotransmission on obstructive sleep apnea.

Arbutin ameliorates hyperglycemia, dyslipidemia and oxidative stress and modulates adipocytokines and PPARγ in high-fat diet/streptozotocin-induced diabetic rats

Arbutin is a glycosylated hydroquinone with antioxidant and anti-hyperglycemia effects. However, its beneficial effects in type 2 diabetes (T2D) were not clarified. This study evaluated the effect of arbutin on hyperglycemia, dyslipidemia, insulin resistance, oxidative stress, and inflammatory response in T2D. Rats induced by high fat diet and streptozotocin were treated with arbutin (25 and 50 mg/kg for 4 weeks). Diabetic rats exhibited glucose intolerance, elevated HbA1c%, reduced insulin, and high HOMA-IR. Liver glycogen and hexokinase activity were decreased in T2D rats while glucose-6-phosphatase (G6Pase), fructose-1,6- biphosphatase (FBPase), and glycogen phosphorylase were upregulated. Circulating and hepatic cholesterol and triglycerides and serum transaminases were elevated in T2D rats. Arbutin ameliorated hyperglycemia, dyslipidemia, insulin deficiency and resistance, and liver glycogen and alleviated the activity of carbohydrate-metabolizing enzymes. Both doses of arbutin decreased serum transaminases and resistin, and liver lipids, TNF-α, IL-6, malondialdehyde and nitric oxide, downregulated liver resistin and fatty acid synthase, and increased serum and liver adiponectin, and liver reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT). These effects were associated with the upregulation of hepatic PPARγ. Arbutin inhibited α-glucosidase in vitro and in silico investigations revealed the ability of arbutin to bind PPARγ, hexokinase, and α-glucosidase. In conclusion, arbutin effectively ameliorated glucose intolerance, insulin resistance, dyslipidemia, inflammation, and oxidative stress, and modulated carbohydrate-metabolizing enzymes, antioxidants, adipokines and PPARγ in T2D in rats.

The protective effect of arbutin against potassium bromate-induced oxidative damage in the rat brain

This study aimed to investigate the protective effects of arbutin (ARB) against brain injury induced in rats with potassium bromate (KBrO₃ ). The rats were divided into four groups as Group 1: Control (0.9% NaCl ml/kg/day p.), Group 2: KBrO₃ (100 mg/kg (gavage), Group 3: ARB (50 mg/kg/day p.), and Group 4: KBrO₃  + ARB (100 mg/kg (gavage) + 50 mg/kg/day p.). At the end of the fifth day of the study, the rats in all groups were killed, and their brain tissues were collected. In the collected brain tissues, malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels were measured, and routine histopathological examinations were made. The MDA levels in the group that was exposed to KBrO₃ were significantly higher than those in the control group (p ˂ 0.001). In comparison to the KBrO₃ group, the MDA levels in the KBrO₃  + ARB group were significantly lower (p ˂ 0.001). It was observed that SOD and CAT enzyme activity levels were significantly lower in the KBrO₃ group compared to the control group (p ˂ 0.001), while these levels were significantly higher in the KBrO₃  + ARB group than in the KBrO₃ group (p ˂ 0.001). Additionally, the group that was subjected to KBrO₃ toxicity, as well as ARB administration, had much lower levels of histopathologic signs than the group that was subjected to KBrO₃ toxicity only. Consequently, it was found that KBrO₃ exposure led to injury in the brain tissues of the rats, and using ARB was effective in preventing this injury.

Arbutin-modified microspheres prevent osteoarthritis progression by mobilizing local anti-inflammatory and antioxidant responses

Osteoarthritis (OA) is a common degenerative joint disease worldwide and currently there is no effective strategy to stop its progression. It is known that oxidative stress and inflammation can promote the development of OA, and therapeutic strategies against these conditions may alleviate OA. Arbutin (ARB), a major ingredient of the Chinese medicinal herb cowberry leaf, exerts good antioxidant and anti-inflammatory activities yet has not been studied in OA. Here we developed ARB-loaded gelatine methacryloyl-Liposome (GM-Lipo@ARB) microspheres which showed long-term release of ARB and excellent cartilage-targeting effects. The ARB-loaded microspheres effectively reduced the inflammatory response in interleukin (IL)-1β-treated arthritic chondrocytes. Moreover, the synthesized GM-Lipo@ARB microspheres regulated cartilage extracellular matrix (ECM) homeostasis through anti-inflammation effect via inhibiting NF-κB signaling and anti-oxidative stress effect via activating Nrf2 pathway. Intra-articular use of GM-Lipo@ARB can effectively reduce inflammation and oxidative stress in the articular cartilage and thus, attenuating OA progression in a mouse model. The study proposed a novel ARB-laden functional microsphere, GM-Lipo@ARB, and demonstrated that this compound may be used as an alternative therapeutics for treating OA.