Alzheimer's Disease Rats Research Articles

Pretreatment with Liposome-Encapsulated Shrimp Shell Extract Attenuated Neuronal Damage and Death in Aβ1-42-Induced Memory Deficits in Rats.

The accumulation of amyloid-beta (Aβ) peptides is a crucial factor in the neuronal degeneration of Alzheimer's disease (AD). The current study investigated the underlying neuroprotective mechanisms of shrimp shell extract (SSE) and liposome-encapsulated SSE (SSE/L) against Aβ1-42-induced neuronal damage and death in rats. Intracerebroventricular infusion of Aβ1-42 effectively induced memory decline, as observed in a reduction of the rat's discriminating ability in the novel object recognition and novel object location tasks. Oral pretreatment with 100mg/kg of SSE demonstrated no preventive effect on the memory decline induced by Aβ1-42 infusion. However, treatment with SSE/L 100mg/kg BW effectively attenuated memory deficits in both behavioral assessments following two and four weeks after Aβ1-42 infusion. Moreover, SSE/L exerted neuroprotective effects by reducing lipid peroxidation and increasing Nrf2/HO-1 expression. There was a significant decrease in Iba1 and GFAP (biomarkers of microglia and astrocyte activity, respectively), as well as a decrease in the levels of NF-κB expression and the inflammatory cytokines TNF-α and IL-6 in the cortical and hippocampal tissues. Treatment with SSE/L also reduced the pro-apoptotic proteins Bax and cleaved caspase-3 while raising the anti-apoptotic protein Bcl2. In addition, the beneficial effects of SSE/L were along with the effects of a positive control commercial astaxanthin (AST). The findings of this study indicated that SSE/L provided neuroprotective effects on Aβ1-42-induced AD rats by ameliorating oxidative stress, neuroinflammation and apoptotic cell death. Therefore, SSE/L might be employed to prevent and mitigate Aβ accumulation-induced neurotoxicity in AD.

The effect of 8 weeks of interval training combined with the consumption of cineole, linalool, and bourbonene on MAPK/Arc gene expression and learning in rats with Alzheimer’s disease

Background and aims: This research aimed to investigate the effect of 8 weeks of interval training and the use of cineole, linalool, and bourbonene on MAPK/Arc gene expression and learning in Alzheimer’s disease (AD) rats. Methods: In this experimental study, 40 AD rats were randomized into eight groups, including (1) control, (2) AD, (3) AD+aerobic training (AT), (4) AD+linalool, cineole, and bourbonene (LCB), (5) AD+AT+LCB, (6) AT+AD, (7) LCB+AD, and (8) AT+LCB+AD. AD was induced by injecting amyloid-beta (Aβ1)-42 into the hippocampus of rats. The interval training protocol was performed five days per week for eight weeks before and after AD induction. Linalool at a concentration of 25 mg/kg, cineole at a concentration of 10 µM, and β-bourbonene at a concentration of 10 µg/mL were used for eight weeks. One-way analysis of variance was used for between-group comparisons, and Tukey’s test was used for pairwise comparisons at P≤0.05. Results: AD induction caused a significant decrease in MAPK/Arc gene expression in hippocampal tissue (P=0.001). Interval exercise and consumption of three herbal drugs significantly increased gene expression of Arc (P=0.001) and MAPK (P=0.001). AD induction decreased learning (P=0.001). Interval exercise and consumption of three herbal medicines caused a significant increase in learning (P=0.001). Conclusion: Interval exercise and using three herbal medicines have more favorable effects on improving MAPK/Arc gene expression and learning in AD than each alone.

Role Of Lncrna In Alzheimer’s Diseases

Long noncoding RNA (lncRNA) are a family of RNA molecules with over 200 nucleotides in size. They cannot code for proteins but still have biological activities. lncRNAs are abundantly expressed in the pathogenic process of neurological diseases like Alzheimer’s. The lncRNA EBF3-AS is more expressed in the brains of older Alzheimer's disease patients called late onset Alzheimer’s disease. NAT-Rad18, a lncRNA over synthesized in specific areas of the brain in AD rats. The lncRNA n336694 targets miR-106b which increases its expression. MiR-106b leads to apoptosis markers in cells. oxidative stress-induced injury to the neurons is caused by the lncRNA SOX21-AS1. The lncRNA-ATB is involved in AD pathophysiology and reducing its expression helps with oxidative stress-induced injury. lncRNA MEG3 inhibits inflammatory injury and oxidative stress in individuals suffering from AD. The increase of lncRNA 17A in cerebral tissues of AD patients affects Aβ secretion. BACE1-AS suppression reduces Aβ and BACE1 levels and inhibits tau protein phosphorylation (3). The lncRNA BC200, also known as BCYRN1 upregulates Aβ production through BACE1 modulation which leads to AD pathogenesis. NEAT1 regulates the miR-124/BACE1 axis and plays a role in AD development. Reduced SORL1 expression increases neurotoxic Aβ formation in AD brains. LRP1-AS negatively regulates systemic Aβ clearance during AD progression. GAS5 regulates insulin signaling, neuronal survival, tau phosphorylation, and neuroinflammation. MAGI2-AS3-miR-374b-5p axis modulates neuroinflammation and neurotoxicity caused by Aβ fragment. Upregulation of WT1-AS inhibits the miR-375/SIX4 axis, OSI, and neuronal apoptosis in AD. BDNF-AS is found to be important in AD though the mechanism has yet to be determined. This review study aims to enhance comprehension of the disease progression of Alzheimer's disease (AD) in relation to various long non-coding RNAs (lncRNA).

Correction of mitochondrial dysfunction with trimethoxy-substituted monocarbonyl curcumin analogues in experimental Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disease that is a terminal form of dementia with an alarming spread rate. The treatment of AD usually involves symptomatic therapy, but the research field for new medicines to correct AD focus on the pathogenetic keys of the disease, i.e., a mitochondrial dysfunction.The aim of the work was to evaluate the effect of trimethoxy-substituted monocarbonyl curcumin analogues on changes in the mitochondrial function of the hippocampus in AD rats.Materials and methods. AD was modeled in female Wistar rats by the injection of β-amyloid aggregates 1-42 into the CA1 part of the hippocampus. The tested compounds AZBAX4 and AZBAX6 at a dose of 20 mg/kg each, as well as the reference donepezil at a dose of 50 mg/kg, were administered orally for 30 days after the surgery. After the specified time had passed, the changes in the cellular respiration, a citrate synthase activity, cytochrome-c-oxidase, succinate dehydrogenase, and adenosine triphosphate (ATP) concentrations were evaluated in the mitochondrial fraction of the rat hippocampus.Results. During the study, it was shown that the use of AZBAX4 and AZBAX6 compounds contributed to an increase in the intensity of aerobic metabolism by 83.9 (p <0.05) and 35.9% (p <0.05), respectively, while reducing the activity of anaerobic one by 27.7 (p <0.05) and 20.6% (p <0.05), respectively. Against the background of the tested compounds AZBAX4 and AZBAX6 administration, there was also a significant increase in the activity of citrate synthase, succinate dehydrogenase and cytochrome-c-oxidase, as well as the level of ATP in the hippocampal tissue by 112.8 (p <0.05) and 117.1% (p <0.05), respectively. The use of donepezil led to a significant increase in the intensity of aerobic reactions – by 24.0% (p <0.05), a citrate synthase activity– by 80.0% (p <0.05) and the ATP concentration – by 68.5% (p <0.05). Against the background of the use of the analyzed substances, a decrease in the apoptosis-inducing factor and mitochondrial hydrogen peroxide is also worth noting.Conclusion. Based on the obtained data, it can be assumed that the use of AZBAX4 and AZBAX6 compounds contributes to an increase in the functional activity of the mitochondria of hippocampal cells of AD rats, while surpassing the reference donepezil. It is perspective to continue a further study of AZBAX4 and AZBAX6 compounds as possible medicines of a pathogenetic correction of AD.

Nanoencapsulated Curcumin: Enhanced Efficacy in Reversing Memory Loss in An Alzheimer Disease Model.

Investigating new drugs or formulations that target Alzheimer disease (AD) is critical for advancing therapeutic interventions. Therefore, this study aimed to assess the effectiveness of nanoencapsulated curcumin (NC Curc) in alleviating memory impairment, oxidative stress, and neuroinflammation in a validated AD model. Male Wistar rats were given bilateral intracerebroventricular injections of either saline or streptozotocin (STZ) (3 mg/3 µL/site) to establish the AD model (day 0). On day 22, daily oral administrations of curcumin (6 mg/kg), NC Curc (6 mg/kg), or a vehicle (unloaded NC) were initiated and continued for 14 days. NC Curc significantly reversed memory deficits in object recognition and inhibitory avoidance tests induced by STZ. Both formulations of curcumin attenuated elevated acetylcholinesterase activity caused by STZ. Importantly, NC Curc alone effectively mitigated STZ-induced oxidative stress. Additionally, NC Curc treatment normalized GFAP levels, suggesting a potential reduction in neuroinflammation in STZ-treated rats. Our findings indicate that NC Curc improves memory in an AD rat model, highlighting its enhanced therapeutic effects compared to unencapsulated curcumin. This research significantly contributes to understanding the therapeutic and neurorestorative potential of NC Curc in AD, particularly in reversing pathophysiological changes.

The effect of 12 weeks of endurance training with sumac intake on the serum levels of nitric oxide and interleukin-1 beta in Alzheimer's male rats

Introduction: Alzheimer's is one of the most common dementia diseases. Exercise along with antioxidant substances can prevent the progress of this condition. Therefore, the aim of this study was to investigate the effect of 12 weeks of endurance training with sumac intake on the serum levels of nitric oxide and interleukin-1 beta in Alzheimer's male rats. Materials and methods: In this experimental study, 35 male Wistar rats were randomly divided into 5 groups (healthy control, Alzheimer's, Alzheimer's with endurance exercise, Alzheimer's with sumac, Alzheimer's with endurance exercise and sumac ). In order to induce Alzheimer's disease, 8 mg of trimethyl tin chloride was injected. Sumac powder was used at a ratio of 10%. Endurance swimming exercises in water were 5 days a week and lasted 15 to 60 minutes in each session. 48 hours after the last training session, interleukin-1 beta and nitric oxide serum levels were measured by ELISA method. The data were analyzed by one-way ANOVA and Dunnett's test at a significance level of P<0.05. Findings: The level of interleukin-1 beta in the sumac + endurance training group was lower than the other groups, and the nitric oxide levels in the sumac and endurance training group were significantly higher than the Alzheimer's group (P=0.001). However, the amount of nitric oxide in the sumac group with endurance training was not significantly different from the healthy group (P<0.05). Conclusion: The results suggest that endurance exercise and taking sumac is associated with the improvement of inflammatory factors and the combination of these two interventions leads to a doubling of the improvement.

Interaction of aerobic exercise and crocin improves memory, learning and hypocampic tau and neurotrophins gene expression in rats treated with trimethytin as a model of Alzheimer's disease.

Alzheimer's disease (AD) is characterized by progressive cognitive decline and a reduction in hippocampal neurotrophins, in which trimethytin (TMT) infusion causes tangles and neuronal dysfunction, creating an AD-like model in rats. Previous studies have demonstrated that crocin, which has anti-inflammatory properties, can enhance learning, memory acquisition, and cognitive behavior. This study aimed to assess the combined impact of aerobic exercise and crocin on memory, learning, and hippocampal Tau and neurotrophins gene expression in AD-like model rats. Forty male Sprague Dawley rats were randomly divided into five groups: (1) healthy control, (2) Alzheimer's control, (3) endurance training, (4) crocin consumption, and (5) endurance training + crocin. Alzheimer's induction was achieved in groups 2-5 through intraperitoneal injection of 8 mg/kg TMT. Rats in groups 3 and 5 engaged in treadmill running three sessions per week, 15-30 min per session, at a speed of 15-20 m/min for eight weeks, and groups 4 and 5 received daily crocin supplementation of 25 mg/kg. Alzheimer's induction with TMT showed significant reduction in memory, learning, NGF, BDNF, and TrkB gene expression, and increase in tau gene expression (all p < 0.05). Notably, endurance training and crocin consumption separately significantly increased memory, learning, NGF, BDNF, and TrkB gene expression while significantly decreasing tau gene expression (all p < 0.05). Importantly, combined endurance training with crocin yielded the most profound effects on memory (p = 0.001), NGF (p = 0.002), BDNF (p = 0.001), and TrkB (p = 0.003) gene expression (p < 0.005), as well as a reduction in tau gene expression (p = 0.001). These findings underscore the possible impact of endurance training, particularly when coupled with crocin, on enhancing memory, learning, and neurotrophin gene expression and reducing tau gene expression in Alzheimer's rats. These results highlight the possibility of synergistic interventions for improved therapeutic outcomes.

Simple and Complex Wheel Running Effect on Depression, Memory, Neuroinflammation, and Neurogenesis in Alzheimer's Rat Model.

The aim of this study was to investigate 12 wk of simple and complex voluntary wheel running on Alzheimer's disease (AD), associated biomarkers, and behaviors. Sixty male Wistar rats were randomly divided into six groups: healthy control (Con-Sed), AD only (AD-Sed), simple wheel control (SWC), complex wheel control (CWC), simple wheel AD (SWAD), and complex wheel AD (CWAD). Novelty-suppressed feeding test and the Morris water maze test were used to evaluate depression and memory, respectively. Ki67 was measured in the hippocampus, whereas interleukin (IL)-1β and neural/glial antigen 2 (NG2) were measured in both the hippocampus and the prefrontal cortex. One-way ANOVA with Tukey's post hoc test was performed. AD-Sed group had significantly lower spacial memory ( P < 0.001) compared with Con-Sed. Simple and complex wheel running attenuated these deficits in the SWAD and CWAD groups, respectively ( P < 0.001). Only the CWAD group had significantly improved novelty-suppressed feeding test time compared with AD-Sed ( P < 0.001), equivalent to the healthy wheel running groups. AD-Sed has significantly higher hippocampal concentrations of Ki67 ( P = 0.01) compared with the Con-Sed. Both SWAD and CWAD had significantly reduced Ki67 with similar concentrations compared with the SWC and CWC groups ( P > 0.05). AD-Sed animals also presented with significantly higher hippocampal and prefrontal cortex concentrations of IL-1β compared with Con-Sed ( P < 0.001). SWAD and CWAD had no effect in changing these concentrations. Complex wheel running significantly increased NG2 in the healthy control and AD models, whereas simple wheel running significantly increased NG2 in the AD model. The results of our study suggest that complex wheel running might be more advantageous in promoting memory and neuroplasticity while reducing depression that is associated with AD.

Danggui Shaoyao San: comprehensive modulation of the microbiota-gut-brain axis for attenuating Alzheimer's disease-related pathology.

Background: Alzheimer's disease (AD), an age-associated neurodegenerative disorder, currently lacks effective clinical therapeutics. Traditional Chinese Medicine (TCM) holds promising potential in AD treatment, exemplified by Danggui Shaoyao San (DSS), a TCM formulation. The precise therapeutic mechanisms of DSS in AD remain to be fully elucidated. This study aims to uncover the therapeutic efficacy and underlying mechanisms of DSS in AD, employing an integrative approach encompassing gut microbiota and metabolomic analyses. Methods: Thirty Sprague-Dawley (SD) rats were allocated into three groups: Blank Control (Con), AD Model (M), and Danggui Shaoyao San (DSS). AD models were established via bilateral intracerebroventricular injections of streptozotocin (STZ). DSS was orally administered at 24g·kg-1·d-1 (weight of raw herbal materials) for 14 days. Cognitive functions were evaluated using the Morris Water Maze (MWM) test. Pathological alterations were assessed through hematoxylin and eosin (HE) staining. Bloodstream metabolites were characterized, gut microbiota profiled through 16S rDNA sequencing, and cortical metabolomics analyzed. Hippocampal proinflammatory cytokines (IL-1β, IL-6, TNF-α) were quantified using RT-qPCR, and oxidative stress markers (SOD, CAT, GSH-PX, MDA) in brain tissues were measured with biochemical assays. Results: DSS identified a total of 1,625 bloodstream metabolites, predominantly Benzene derivatives, Carboxylic acids, and Fatty Acyls. DSS significantly improved learning and spatial memory in AD rats and ameliorated cerebral tissue pathology. The formulation enriched the probiotic Ligilactobacillus, modulating metabolites like Ophthalmic acid (OA), Phosphocreatine (PCr), Azacridone A, Inosine, and NAD. DSS regulated Purine and Nicotinate-nicotinamide metabolism, restoring balance in the Candidatus Saccharibacteria-OA interplay and stabilizing gut microbiota-metabolite homeostasis. Additionally, DSS reduced hippocampal IL-1β, IL-6, TNF-α expression, attenuating the inflammatory state. It elevated antioxidative enzymes (SOD, CAT, GSH-PX) while reducing MDA levels, indicating diminished oxidative stress in AD rat brains. Conclusion: DSS addresses AD pathology through multifaceted mechanisms, encompassing gut microbiome regulation, specific metabolite modulation, and the mitigation of inflammation and oxidative stress within the brain. This holistic intervention through the Microbial-Gut-Brain Axis (MGBA) underscores DSS's potential as an integrative therapeutic agent in combatting AD.

Anti-Alzheimer potential of Solanum lycopersicum seeds: in vitro, in vivo, metabolomic, and computational investigations

Abstract Background Solanum lycopersicum Linn. (Tomato, Family Solanaceae) is one of the fruits that are most consumed worldwide. The current research intends to emphasise the possibility of positive and therapeutic effects of S. lycopersicum seed extract (SLSE) on Alzheimer's disease's neurodegeneration effects being reversed in a study utilising rats exposed to aluminium chloride. Investigations were done on the cholinesterase and antioxidant in vitro activity of SLSE. Rats with Alzheimer's disease were given SLSE, and donepezil (500, and 10 mg/kg.b.wt., daily for six weeks, respectively) to test SLSE biological activity. Beam-balance and T-maze tests, as well as serum levels of AChE, norepinephrine, dopamine, serotonin, IL-6, glycated end product, BDNF, MDA, TAC, and GSH were assessed, accompanied with histological investigation. To impact the effectiveness of this extract, bioinformatics study was validated. Results Crude SLSE showed in vitro DPPH scavenging and AChE inhibition activities, indicating the extract might have anti-Alzheimer potential, which was validated using an aluminium-intoxicated rat model, in vivo. In Alzheimer's rats, in vivo studies showed considerable improvements, as seen by improved beam balance, and T-maze tests and decreased serum levels of AChE, norepinephrine, dopamine, serotonin, IL-6, glycated end product, BDNF, and MDA, with increasing in TAC, and GSH levels. Brain tissue histological tests revealed a largely typical pattern of collagen fibre distribution. LC–HRESIMS metabolomic profiling of crude SLSE identified 33 compounds. Furthermore, the bioinformatics study discovered 378 targets related to the major identified compounds, of which only 133 were related to Alzheimer's and memory disorders, with APP, AChE, and PSEN2 targets which were marked as the top genes. Gene enrichment analysis identified the arachidonic acid metabolism and PPAR signalling pathway as the biological pathways enriched by all the gene sets under investigation. Conclusion As a result, the study findings are expected to pave the way for the creation of dietary supplements for Alzheimer's disease management. Graphic abstract

Cacao Ameliorates Amyloid Beta-Induced Cognitive and Non-Cognitive Disturbances.

Alzheimer's disease (AD) is a progressive neurological disorder characterized by a wide range of cognitive and non-cognitive impairments. The present study was designed to investigate the potential effects of cacao on cognitive and non-cognitive performance and to identify the role of oxidative stress in an AD animal model induced by unilateral intracerebroventricular (U-ICV) injection of amyloid beta1-42 (Aβ1-42). Oral administration of cacao (0.5 g/kg/day) was performed for 60 consecutive days. Following 60 days, the open-field (OF) test, elevated plus-maze (EPM) test, novel object recognition (NOR) test, Barnes maze (BM) test, and Morris water maze (MWM) test were used to evaluate locomotor activity, anxiety-like behavior, recognition memory, and spatial memory, respectively. Total oxidant status (TOS) and total antioxidant capacity (TAC) in plasma were also examined. Furthermore, the number of healthy cells in the hippocampus's dentate gyrus (DG), CA1, and CA3 regions were identified using hematoxylin and eosin staining. The results indicated that the injection of Aβ1-42 in rats led to recognition memory and spatial memory impairments, as well as increased anxiety. This was accompanied by decreased total antioxidant capacity (TAC), increased total oxidative stress (TOS), and increased neuronal death. Conversely, cacao treatment in AD rats improved memory function, reduced anxiety, modulated oxidative stress balance, and decreased neuronal death. The findings suggest that cacao's ability to improve the balance between oxidants and antioxidants and prevent neuronal loss may be the mechanism underlying its beneficial effect against AD-related cognitive and non-cognitive impairments.

Tau‑targeting multifunctional nanocomposite based on tannic acid-metal for near-infrared fluorescence/magnetic resonance bimodal imaging-guided combinational therapy in Alzheimer's disease.

Rationale: Alzheimer's disease (AD) is hallmarked by amyloid-β (Aβ) plaques and hyperphosphorylated tau (p-tau) neurofibrillary tangles. While Aβ-centric therapies have shown promise, the complex pathology of AD requires a multifaceted therapeutic approach. The weak association between Aβ levels and cognitive decline highlights the need for alternative theranostic strategies. Currently, oxidative stress and tau hyperphosphorylation are now recognized as critical pathological events in AD. Thus, therapies that concurrently attenuate oxidative stress damage and inhibit tau pathology hold great potential for AD treatment. Methods: Herein, a multifunctional neuron-targeted nanocomposite is devised to realize dual imaging-guided AD therapy, integrating the inhibition of tau pathology and reactive oxygen species (ROS)-neutralizing biofunctions. The construction of the nanocomposite incorporates polyphenolic antioxidants tannic acid (TA)-based nanoparticles carrying manganese ions (Mn2+) and fluorescent dye IR780 iodide (IR780), coupled with a neuron-specific TPL peptide. The resulting IR780-Mn@TA-TPL nanoparticles (NPs) are comprehensively evaluated in both in vitro and in vivo AD models to assess their imaging capabilities and therapeutic efficacy. Results: The nanocomposite facilitates Mn-enhanced magnetic resonance (MR) imaging and near-infrared (NIR) fluorescence imaging. It effectively neutralizes toxic ROS and reduces tau hyperphosphorylation and aggregation. In AD rat models, the nanocomposite restores neuronal density in the hippocampus and significantly improves spatial memory. Conclusions: Such a neuron‑targeting multifunctional nanocomposite represents a potential theranostic strategy for AD, signifying a shift towards bimodal imaging-guided treatment approaches.

Crocin nano-chitosan-coated compound improves anxiety disorders, learning, and spatial memory in Alzheimer's model induced by beta-amyloid in rats.

Alzheimer's disease (AD) is a neurodegenerative disease that results in the gradual breakdown of brain tissue, causing the deterioration of intellectual function and ability. Crocin is a saffron carotenoid compound proven to have excellent neuroprotective and anti-inflammation properties, although it has some limitations such as low stability and bioavailability. Therefore, in the current research, we tried to improve these limitations by using nanotechnology and chitosan as the carrier. Our study examined the therapeutic effects of crocin nano-chitosan-coated compound and compared it with intact crocin in lower dosages than other studies in AD rat models. Encapsulating crocin into chitosan nanoparticles was done through a modified technique to improve its limitations. The AD rat model was induced by bilaterally injecting beta-amyloid (Aβ) peptide into the frontal lobe using a stereotaxic device. To evaluate memory, we conducted the Barnes maze test, and to evaluate anxiety, we used the elevated plus maze test. Also, histological tests were conducted to evaluate neuronal damage in each group. Crocin nano-chitosan-coated administration significantly improved specific memory indicators compared to the Aβ and other treated groups. A significant decrease in anxiety indicators was detected compared to the Aβ and other treated groups. Finally, the results of hippocampus staining indicated a meaningful difference between the Aβ group and other treated groups, compared to the crocin nano-chitosan-coated group. Treatment with low dosages of crocin in the nano-coated form exhibited great efficacy in reducing AD's adverse effects compared to the same dosage of intact crocin.

Amelioration of Amyloid-β Induced Alzheimer's Disease by Bacopa monnieri through Modulation of Mitochondrial Dysfunction and GSK-3β/Wnt/β-Catenin Signaling.

Alzheimer's disease (AD) is the most prevalent dementia, affecting a large number of populations. Despite being under scrutiny for decades, an effective therapeutic option is still not available. This study explores the therapeutic role of a nootropic herb Bacopa monnieri (BM) in AD-like pathological conditions produced by injecting preformed amyloid-β42 (Aβ42) fibril bilaterally into hippocampus of Wistar rats, and ethanolic extract of BM is orally administered for 4 weeks. Assessment of behavioral changes reveals that BM treatment ameliorates Aβ42-induced cognitive impairment and compromised explorative behavior. Supplementation of BM also reduces oxidative stress biomarkers, proinflammatory cytokines, and cholinesterase activity in the AD rats. Additionally, BM treatment restores Bcl-2-associated X protein (Bax)/ B-cell lymphoma 2 (Bcl-2) imbalance, increases neurotrophic factors expression, and prevents neurodegeneration validated by quantifying Nissl-positive hippocampal neurons. Interestingly, BM administration eliminates amyloid plaques in the hippocampal region and normalizes the Aβ42-induced increase in phospho-tau and total tau expression. Mechanistic investigations reveal that BM interacts with glycogen synthase kinase (GSK-3β) and restores Wnt/β-catenin signaling. BM has been used in diet as a nootropic herb for several centuries. This study highlights the anti-Alzheimer activity of BM from the behavioral to the molecular level by modulating mitochondrial dysfunction, and GSK-3β mediates the Wnt/β-catenin signaling pathway.

UPLC-Q-TOF/MS based serum and urine metabolomics strategy to analyze the mechanism of nervonic acid in treating Alzheimer’s disease

Nervonic acid is a natural component of breast milk and is frequently used as a food additive due to its excellent neuroprotective effects. Although it has been reported that nervonic acid may play a role in the recovery of human cognitive impairment, its specific mechanism of action is still unclear. In this study, the results of serum biochemical indexes showed that nervonic acid improved inflammation and reduced amyloid β peptide (Aβ) deposition and tau protein phosphorylation in Alzheimer’s disease (AD) rats. Subsequently, we further used a metabolomics approach to investigate the potential mechanism of action of nervonic acid in the treatment of AD. The results of serum and urine metabolomics study showed that the intervention of nervonic acid significantly reversed the metabolic profile disorder in AD rats. A total of 52 metabolites were identified. They mainly involved linoleic acid metabolism, alpha-linolenic acid metabolism, phenylalanine metabolism and arachidonic acid metabolism, and all these metabolic pathways were associated with the emergence of inflammation in vivo. It suggests that the therapeutic effect of nervonic acid on AD is likely to be produced by ameliorating inflammation. The results obtained in this study provide new insights into the mechanism of nervonic acid treatment of AD and lay a foundation for the clinical application of nervonic acid in the treatment of Alzheimer’s disease.

Coconut oil ameliorates behavioral and biochemical alterations induced by D-GAL/AlCl3 in rats

Alzheimer's disease (AD) is a chronic, progressive neurodegenerative condition marked by cognitive impairment. Although coconut oil has been shown to be potentially beneficial in reducing AD-related cognitive deficits, information on its mechanism of action is limited. Thus, we investigated the effects of coconut oil on spatial cognitive ability and non-cognitive functions in a rat model of AD induced by G-galactose (D-GAL) and aluminum chloride (AlCl3), and examined the changes in synaptic transmission, cholinergic activity, neurotrophic factors and oxidative stress in this process. The AD model was established by administering D-GAL and AlCl3 for 90 days, while also supplementing with coconut oil during this time. Cognitive and non-cognitive abilities of the rats were evaluated at the end of the 90-day supplementation period. In addition, biochemical markers related to the pathogenesis of the AD were measures in the hippocampus tissue. Exposure to D-GAL/AlCl3 resulted in a reduction in locomotor activity, an elevation in anxiety-like behavior, and an impairment of spatial learning and memory (P < 0.05). The aforementioned behavioral disturbances were observed to coincide with increased oxidative stress and cholinergic impairment, as well as reduced synaptic transmission and levels of neurotrophins in the hippocampus (P < 0.05). Interestingly, treatment with coconut oil attenuated all the neuropathological changes mentioned above (P < 0.05). These findings suggest that coconut oil shows protective effects against cognitive and non-cognitive impairment, AD pathology markers, oxidative stress, synaptic transmission, and cholinergic function in a D-GAL/AlCl3-induced AD rat model.

Temporal evaluation of imaging and biofluid biomarkers, spatial neuropathology and glial function in the TgF344‐AD rat model

AbstractBackgroundThe development and characterization of Alzheimer’s disease (AD) animal models is particularly important for the investigation of pathophysiological mechanisms and drug development. The TgF344‐AD rat is a model harboring human APP/PS1 mutations with comprehensive presentation, including age‐dependent development of amyloid‐β (Aβ) plaques, neuronal loss and tau deposits, but not yet fully characterized. In light of this, we evaluated imaging and biofluid biomarkers, spatial neuropathology and glial function in these animals across multiple key ages.MethodsTgF344‐AD rats and wild‐type littermates were longitudinally evaluated at 3, 6, 9, 12 and 16‐18 months of age. Rats underwent [18F]FDG‐microPET scans and CSF samplings. CSF glial and immune markers (GFAP, S100B, TREM2, IL‐6, TNF‐α, IL‐10) were measured by multiplex immunoassay. A cross‐sectional cohort was used to measure cortical glutamate uptake (ex‐vivo slices) and follow the spatial distribution of Aβ plaques (6E10 antibody) at the same time points.ResultsAt 3, 6, 12 and 16‐18mo, no changes in [18F]FDG metabolism were observed. At 9mo, we identified a significant cortical hypermetabolism in the TgF344‐AD rats. CSF GFAP levels were elevated at 6 and 9 months of age, while CSF S100B was decreased at 9mo. The CSF inflammatory markers IL‐6, TNF‐α and IL‐10 were elevated at 16‐18mo. Additionally, the glutamate uptake was increased in the cortex at 9mo and 12mo, and in the hippocampus at 12mo. TREM2 was not altered in any of the ages evaluated. The (Aβ) plaques deposition starts at 6mo in the posterior temporal cortices and hippocampus and spreads slowly to frontal brain regions, reaching a plateau around 16mo.ConclusionThis work shows that the TgF344‐AD rat model recapitulates the early and transient glucose hypermetabolism seen in AD patients. Our results also indicate an associated early astrocyte response in these animals, with changes in relevant astrocyte biomarkers and function (glutamate uptake). Due to the critical role of astrocytes in brain glucose handling, these findings suggest that astrocyte reactivity could be driving glucose hypermetabolism. In contrast, the neuroinflammatory biomarkers changes identified suggest a strong neuroinflammatory response only at later stages in this rat model, however, further investigations are necessary to better elucidate these findings.

Association between glial and synaptic fluid biomarkers and brain [18F]FDG‐PET signal

AbstractBackgroundBeyond the hypometabolic signature, indexed by [18F]FDG‐PET imaging, seen in the brain of Alzheimer’s disease (AD) patients, a transient brain glucose hypermetabolism has been recently identified in the early stages of AD. The cellular source of this dual metabolic response remains controversial, with glial cells gaining a lot of attention. In light of this, whether glial and synaptic fluid biomarkers are associated with [18F]FDG‐PET signal in the early stages of AD remains debatable. Thus, we evaluated the association of astrocyte, microglial and synaptic fluid biomarkers with [18F]FDG‐PET signal in an AD rat model.Method[18F]FDG‐PET imaging was conducted in ten‐month‐old (early amyloid stage) APP/PS1 (TgF344‐AD, n = 8‐17) and wild‐type (WT, n = 8‐15) rats. Glial (GFAP and sTREM2), synaptic (neurogranin), and amyloid biomarkers (Aß1‐40 and Aß1‐42) were quantified in the cerebrospinal fluid (CSF) and plasma through a multiplex immunoassay. T‐statistical maps of brain [18F]FDG‐PET and those fluid biomarkers were conducted at the voxel level using RMINC. Differences were considered statistically significant at p&lt;0.05 (t&gt;2).ResultA large hypermetabolic cluster was identified in ten‐month‐old TgF344‐AD (Fig. 1AB, local maxima, t(13) = 4.28). We found positive correlations between CSF TREM2 and brain [18F]FDG‐PET signal (Fig. 2AC, local maxima, t(13) = 4.12). In addition, we identified a positive correlation between plasma GFAP and brain [18F]FDG‐PET signal (Fig. 2BC, local maxima, t(13) = 10.62). Plasma TREM2, CSF GFAP, and plasma neurogranin did not associate with brain glucose metabolism.ConclusionOur findings suggest that CSF TREM2 and plasma GFAP are associated with brain metabolism before amyloid load reaches a plateau. Stronger association of plasma GFAP, rather than CSF GFAP, with brain pathology corroborates cross‐sectional human studies. One could argue that [18F]FDG‐PET hypermetabolism identified is likely a response to astrocyte and microglial changes.

Effects of the ethanolic extract of white tea (Camellia Sinensis) on metabolic functions in Alzheimer's disease rat model

Effects of the ethanolic extract of white tea (Camellia Sinensis) on metabolic functions in Alzheimer's disease rat model

Protective effects of Urolithins A and B on learning and memory and anxiety-like behaviors in streptozotocin-induced Alzheimer's rat model

Protective effects of Urolithins A and B on learning and memory and anxiety-like behaviors in streptozotocin-induced Alzheimer's rat model