Mouse Model Of Dementia Research Articles

Suppression of PTBP1 in hippocampal astrocytes promotes neurogenesis and ameliorates recognition memory in mice with cerebral ischemia

The therapeutic potential of suppressing polypyrimidine tract-binding protein 1 (Ptbp1) messenger RNA by viral transduction in a post-stroke dementia mouse model has not yet been examined. In this study, 3 days after cerebral ischemia, we injected a viral vector cocktail containing adeno-associated virus (AAV)-pGFAP-mCherry and AAV-pGFAP-CasRx (control vector) or a cocktail of AAV-pGFAP-mCherry and AAV-pGFAP-CasRx-SgRNA-(Ptbp1) (1:5, 1.0 × 1011 viral genomes) into post-stroke mice via the tail vein. We observed new mCherry/NeuN double-positive neuron-like cells in the hippocampus 56 days after cerebral ischemia. A portion of mCherry/GFAP double-positive astrocyte-like glia could have been converted into new mCherry/NeuN double-positive neuron-like cells with morphological changes. The new neuronal cells integrated into the dentate gyrus and recognition memory was significantly ameliorated. These results demonstrated that the in vivo conversion of hippocampal astrocyte-like glia into functional new neurons by the suppression of Ptbp1 might be a therapeutic strategy for post-stroke dementia.

Beneficial effect of lupeol and metformin in mouse model of intracerebroventricular streptozotocin induced dementia.

This study examines the effectiveness of lupeol and metformin in a mouse model of dementia generated by intracerebroventricular streptozotocin (i.c.v., STZ). Dementia was induced in Swiss mice with the i.c.v. administration of STZ at a dosage of 3mg/kg on the first and third day. The assessment of dementia involved an examination of the Morris Water Maze (MWM) performance, as well as a number of biochemical and histological studies. STZ treatment resulted in significant decrease in MWM performance; various biochemical alterations (increase in brain acetyl cholinesterase (AChE) activity, thiobarbituric acid reactive species (TBARS), nitrite/nitrate, and reduction in nuclear factor erythroid 2 related factor-2 (Nrf-2), reduced glutathione (GSH) levels) and neuroinflammation [increased myeloperoxidase (MPO) activity & neutrophil infiltration]. The administration of Lupeol (50mg/kg & 100mg/kg; p.o.) and Metformin (150mg/kg & 300mg/kg; p.o.) demonstrated a considerable reduction in the behavioral, biochemical, and histological alterations produced by STZ. Low dose combination of lupeol (50mg/kg; p.o.) and Metformin (150mg/kg; p.o.) produced more pronounced effect than that of high doses of either agent alone. It is concluded that Lupeol and Metformin has shown efficacy in dementia with possible synergism between the two and can be explored as potential therapeutic agents for managing dementia of Alzheimer's disease (AD) type.

Targeting terminal pathway reduces brain complement activation, amyloid load and synapse loss, and improves cognition in a mouse model of dementia

Complement is dysregulated in the brain in Alzheimer’s Disease and in mouse models of Alzheimer’s disease. Each of the complement derived effectors, opsonins, anaphylatoxins and membrane attack complex (MAC), have been implicated as drivers of disease but their relative contributions remain unclarified. Here we have focussed on the MAC, a lytic and pro-inflammatory effector, in the AppNL−G−F mouse amyloidopathy model. To test the role of MAC, we back-crossed to generate AppNL−G−F mice deficient in C7, an essential MAC component. C7 deficiency ablated MAC formation, reduced synapse loss and amyloid load and improved cognition compared to complement-sufficient AppNL−G−F mice at 8–10 months age. Adding back C7 caused increased MAC formation in brain and an acute loss of synapses in C7-deficient AppNL−G−F mice. To explore whether C7 was a viable therapeutic target, a C7-blocking monoclonal antibody was administered systemically for one month in AppNL−G−F mice aged 8–9 months. Treatment reduced brain MAC and amyloid deposition, increased synapse density and improved cognitive performance compared to isotype control-treated AppNL−G−F mice. The findings implicate MAC as a driver of pathology and highlight the potential for complement inhibition at the level of MAC as a therapy in Alzheimer’s disease.

Functional BRI2-TREM2 interactions in microglia: implications for Alzheimer’s and related dementias

ITM2B/BRI2 mutations cause Alzheimer’s Disease (AD)-related dementias. We observe heightened ITM2B/BRI2 expression in microglia, a pivotal cell type in AD due to risk-increasing variants in the microglial gene TREM2. Single-cell RNA-sequencing demonstrates a Trem2/Bri2-dependent microglia cluster, underscoring their functional interaction. α-secretase cleaves TREM2 into TREM2-CTF and sTREM2. As BRI2 hinders α-secretase cleavage of the AD-related Aβ-Precursor-Protein, we probed whether BRI2 influences TREM2 processing. Our findings indicate a BRI2-TREM2 interaction that inhibits TREM2 processing in heterologous cells. Recombinant BRI2 and TREM2 proteins demonstrate a direct, cell-free BRI2-TREM2 ectodomain interaction. Constitutive and microglial-specific Itm2b-Knock-out mice, and Itm2b-Knock-out primary microglia provide evidence that Bri2 reduces Trem2 processing, boosts Trem2 mRNA expression, and influences Trem2 protein levels through α-secretase-independent pathways, revealing a multifaceted BRI2-TREM2 functional interaction. Moreover, a mutant Itm2b dementia mouse model exhibits elevated Trem2-CTF and sTrem2, mirroring sTREM2 increases in AD patients. Lastly, Bri2 deletion reduces phagocytosis similarly to a pathogenic TREM2 variant that enhances processing. Given BRI2’s role in regulating Aβ-Precursor-Protein and TREM2 functions, it holds promise as a therapeutic target for AD and related dementias.

To investigate the mechanism of Qizhi Tongluo capsule in improving vascular dementia model mice

To investigate the mechanism of Qizhi Tongluo capsule in improving vascular dementia model mice

104 Targeting terminal pathway in brain reduces complement activation and synapse loss in a mouse model of dementia

104 Targeting terminal pathway in brain reduces complement activation and synapse loss in a mouse model of dementia

Dl-3-n-butylphthalide promotes synaptic plasticity by activating the Akt/ERK signaling pathway and reduces the blood-brain barrier leakage by inhibiting the HIF-1α/MMP signaling pathway in vascular dementia model mice.

DL-3-n-butylphthalide (NBP) exerts beneficial effects on global cognitive functions, but the underlying molecular mechanisms are still poorly understood. The present study aimed to investigate whether NBP mediates synaptic plasticity and blood-brain barrier (BBB) function, which play a pivotal role in the pathogenesis of vascular dementia (VaD), in a mouse model of bilateralcommon carotid artery stenosis (BCAS). NBP was administered to model mice at a dose of 80 mg/kg by gavage for 28 days after surgery. Cognitive function was evaluated by behavioral tests, and hippocampal synaptic plasticity was evaluated by in vivo electrophysiological recording. Cerebral blood flow (CBF), hippocampal volume, and white matter integrity were measured with laser speckle imaging (LSI) and MRI. In addition, BBB leakage and the expression of proteins related to the Akt/ERK and HIF-1α/MMP signaling pathways were assessed by biochemical assays. NBP treatment alleviated cognitive impairment, hippocampal atrophy, and synaptic plasticity impairment induced by BCAS. In addition, NBP treatmentincreased CBF, promoted white matter integrity, and decreased BBB leakage. Regarding the molecular mechanisms, in mice with BCAS,NBP may activate the Akt/ERK signaling pathway, which upregulates the expression of synapse-associated proteins, anditmayalso inhibit the HIF-1α/MMP signaling pathway, therebyincreasing the expression of tight junction (TJ) proteins. In conclusion, our results demonstrated the therapeutic effects of NBP in improving cognitive function via a wide range of targets in mice subjected to BCAS.

PS-B10-12: A NOVEL PLATFORM FOR A LARGE-VOLUME CSF COLLECTION IN THE FREE-BEHAVING MICE AS A PRECLINICAL MODEL FOR BIOMARKER DEVELOPMENT.

Objectives: With the emergence of disease-modifying therapies for dementia including Alzheimers disease and vascular dementia, there is an urgent need for the development of better biomarkers detecting early stage of dementia and predicting rate of progression. Cerebrospinal fluid (CSF) provides close representation of pathophysiological changes occurring in the central nervous system, and CSF biomarkers have proven to be useful for the diagnosis and prognosis of dementia. Preclinical work using mouse models would be useful to explore novel CSF biomarkers; however, detailed characterization of CSF has been challenging due to the difficulty in collecting large amount of CSF from mice. Here, we developed a novel technique that allows consistent recovery of CSF in the awake, free-moving mouse. Methods: Three-month-old C57/B6 male mice were used in this study. A small incision was made on the dura mater over the cisterna magna and a collecting tube was placed and fixed on the surface of the dura mater that CSF can be drawn via the small hole. Roller pump was connected to the tubing and CSF was continually collected in awake mobile mice. Results: We were able to collect a large volume of CSF from an awake mouse over a few days. Brain tissue had no apparent damage after the long-term collection and no detectable level of blood contamination was found in the collected CSF. This technique allowed a serial measurement of CSF biomarkers in a high-temporal resolution and a continuous administration of compounds / drugs into the subarachnoid space of awake mice. Conclusions: This technique would provide the opportunity to identify novel CSF biomarkers using mouse models of dementia.

Fosgonimeton, a Novel Positive Modulator of the HGF/MET System, Promotes Neurotrophic and Procognitive Effects in Models of Dementia

SummaryAll types of dementia, including Alzheimer’s disease, are debilitating neurodegenerative conditions marked by compromised cognitive function for which there are few effective treatments. Positive modulation of hepatocyte growth factor (HGF)/MET, a critical neurotrophic signaling system, may promote neuronal health and function, thereby addressing neurodegeneration in dementia. Here, we evaluate a series of novel small molecules for their ability to (1) positively modulate HGF/MET activity, (2) induce neurotrophic changes and protect against neurotoxic insults in primary neuron culture, (3) promote anti-inflammatory effects in vitro and in vivo, and (4) reverse cognitive deficits in animal models of dementia. Through screening studies, the compound now known as fosgonimeton-active metabolite (fosgo-AM) was identified by use of immunocytochemistry to be the most potent positive modulator of HGF/MET and was selected for further testing. Primary hippocampal neurons treated with fosgo-AM showed enhanced synaptogenesis and neurite outgrowth, supporting the neurotrophic effects of positive modulators of HGF/MET. Additionally, fosgo-AM protected against neurotoxic insults in primary cortical neuron cultures. In vivo, treatment with fosgo-AM rescued cognitive deficits in the rat scopolamine amnesia model of dementia. Although fosgo-AM demonstrated several procognitive effects in vitro and in vivo, a prodrug strategy was used to enhance the pharmacological properties of fosgo-AM, resulting in the development of fosgonimeton (ATH-1017). The effect of fosgonimeton on cognition was confirmed in a lipopolysaccharide (LPS)–induced neuroinflammatory mouse model of dementia. Together, the results of these studies support the potential of positive modulators of HGF/MET to be used as novel therapeutics and suggest the drug candidate fosgonimeton might protect against neurodegeneration and be therapeutic in the management of Alzheimer’s disease and other types of dementia.

GC/MS-Based Urine Metabolomics Study on the Ameliorative Effect of Xanthoceras sorbifolia Extract on Alzheimer's Disease in Mice.

The cause of Alzheimer's disease, the most common type of dementia today, is still unclear, and in current research, there are no drugs that work relatively well. Therefore, the study for new drugs to treat Alzheimer's disease is an urgent research need. Research on the improvement of Alzheimer's disease with extracts of Xanthoceras sorbifolia has been increasing in recent years, but the mechanism is not fully understood. The experiments were conducted to validate the model and analyze the treatment effect through D-galactose and Aβ25–35 induced dementia model mice, using the Morris water maze, to detect the learning behavior and brain tissue section to observe the hippocampal tissue structure of mice. We performed a nontargeted metabolomic analysis of the urine obtained from different groups of mice using gas chromatography-mass spectrometry. Fourteen potential biomarkers were identified in the mice's urine, outlining five metabolic pathways of interest. It was shown that the extracts of Xanthoceras sorbifolia may exert protective effects on mice in dementia models through energy metabolism, neuroinflammation, and antioxidants. This study reveals the potential pathogenesis of Alzheimer's disease and the possible therapeutic mechanism of Xanthoceras sorbifolia, suggests relevant biomarkers, and provides an additional basis for the clinical application of Xanthoceras sorbifolia.

DL-3-n-butylphthalide imparts neuroprotection via Nrf2/SIRT3 pathway in a mouse model of vascular dementia

The goal of this study was to explore the mechanism of action of DL-3-n-butylphthalidein (NBP) the treatment of vascular dementia (VD) in mice. A vascular dementia mouse model was established with repeated cerebral ischemia/reperfusion (I/R), followed by administration of two different doses of NBP for 28 days. A Morris water maze was used to detect any changes in spatial cognition, while H&E staining was used to observe any histopathological changes in the hippocampus. The number of Caspase-3 and Caspase-9 positive neurons in the hippocampal CA1 region were also assessed using immunohistochemistry. The expression of Nrf2, Sirt3, and autophagy-related factors LC3 II/I and p62 in the hippocampus were detected by Western blotting. The results indicated that NBP treatment ameliorated learning and memory deficits, attenuated pathological damage in the CA1 regions, and reduced autophagy and apoptosis via the Nrf2/SIRT3 pathway after repeated cerebral I/R. Therefore, NBP treatment can improve the learning and cognitive memory of VD mice, possibly through the inhibition of autophagy and apoptosis mediated by the Nrf2/SIRT3 signaling pathway.

A standardized black pepper seed extract containing β-caryophyllene improves cognitive function in scopolamine-induced amnesia model mice via regulation of brain-derived neurotrophic factor and MAPK proteins.

β-caryophyllene (BCP), a natural sesquiterpene present in plants, is a selective agonist of cannabinoid receptor type-2 (CB2) of the endocannabinoid system. In this study, we have prepared an extract from Piper nigrum (black pepper) seeds using supercritical fluid extraction, standardized to contain 30% BCP (ViphyllinTM ). The beneficial effects of prophylactic treatment with Viphyllin on cognitive functions were demonstrated in Scopolamine-induced dementia model mice. Male Swiss albino mice (25-30g) were administered with Viphyllin (50mg and 100mg/kg body weight p.o.) or donepezil (1.60mg/kg) for 14days. Subsequently, cognitive deficits were induced by treating the animals intraperitoneally with Scopolamine (0.75mg/kg). The cognitive behavior of mice was evaluated using a novel object recognition test (NORT) and Morris water maze (MWM) test. The brain homogenates were studied for biochemical parameters including cholinesterase activities and antioxidant status. Western blot analysis was performed to investigate the mechanism of action. Viphyllin dose dependently improved the recognition and spatial memory and cholinergic functions in Scop-treated mice. The extract was found protective against Scop-induced oxidative damage and histopathologic changes in the brain. At 100mg/kg Viphyllin markedly reduced the proBDNF/mBDNF ratio (p<.05) and augmented the TrkB expression (p<.01). Viphyllin (100mg/kg) was found to be neuroprotective by reducing the Scop-induced upregulation of p-JNK and p-p38 MAPK proteins, Bax/Bcl-2 ratio, and caspase activation in the brain. Viphyllin also exerted anti-inflammatory effects by downregulating Cox-2, TNF-α, and NOS-2 in Scop-induced mice (p<.05). To summarize, our data encourage Viphyllin as a functional ingredient/dietary supplement for brain health and cognition. PRACTICAL APPLICATIONS: Black pepper is a culinary spice having several medicinal attributes. Essential oils in the seeds of the plant give aroma and flavor to it. Here we have prepared an extract from the seeds of black pepper using supercritical fluid extraction, characterized for the presence of β-caryophyllene (not <30%). This research work further validates the neuroprotective mechanism of the extract in Scopolamine-induced cognitive impairment model mice. The findings from this study strongly suggest the beneficial neuroactive properties of black pepper seed extract having the presence of BCP, a CB2 receptor agonist. It can thus be used potentially as a functional food ingredient for cognition and brain function.

Nasal Rifampicin Improves Cognition in a Mouse Model of Dementia with Lewy Bodies by Reducing α-Synuclein Oligomers.

α-Synuclein oligomers are thought to play an important role in the pathogenesis of dementia with Lewy bodies (DLB). There is no effective cure for DLB at present. Previously, we demonstrated that in APP- and tau-transgenic mice, oral or intranasal rifampicin reduced brain Aβ and tau oligomers and improved mouse cognition. In the present study, we expanded our research to DLB. Rifampicin was intranasally administered to 6-month-old A53T-mutant α-synuclein-transgenic mice at 0.1 mg/day for 1 month. The mice displayed memory impairment but no motor deficit at this age, indicating a suitable model of DLB. α-Synuclein pathologies were examined by the immunohistochemical/biochemical analyses of brain tissues. Cognitive function was evaluated by the Morris water maze test. Intranasal rifampicin significantly reduced the levels of [pSer129] α-synuclein in the hippocampus and α-synuclein oligomers in the visual cortex and hippocampus. The level of the presynaptic marker synaptophysin in the hippocampus was recovered to the level in non-transgenic littermates. In the Morris water maze, a significant improvement in spatial reference memory was observed in rifampicin-treated mice. Taken together with our previous findings, these results suggest that intranasal rifampicin is a promising remedy for the prevention of neurodegenerative dementia, including Alzheimer’s disease, frontotemporal dementia, and DLB.

Antibody Protection against Long-Term Memory Loss Induced by Monomeric C-Reactive Protein in a Mouse Model of Dementia.

Monomeric C-reactive protein (mCRP), the activated isoform of CRP, induces tissue damage in a range of inflammatory pathologies. Its detection in infarcted human brain tissue and its experimentally proven ability to promote dementia with Alzheimer’s disease (AD) traits at 4 weeks after intrahippocampal injection in mice have suggested that it may contribute to the development of AD after cerebrovascular injury. Here, we showed that a single hippocampal administration of mCRP in mice induced memory loss, lasting at least 6 months, along with neurodegenerative changes detected by increased levels of hyperphosphorylated tau protein and a decrease of the neuroplasticity marker Egr1. Furthermore, co-treatment with the monoclonal antibody 8C10 specific for mCRP showed that long-term memory loss and tau pathology were entirely avoided by early blockade of mCRP. Notably, 8C10 mitigated Egr1 decrease in the mouse hippocampus. 8C10 also protected against mCRP-induced inflammatory pathways in a microglial cell line, as shown by the prevention of increased generation of nitric oxide. Additional in vivo and in vitro neuroprotective testing with the anti-inflammatory agent TPPU, an inhibitor of the soluble epoxide hydrolase enzyme, confirmed the predominant involvement of neuroinflammatory processes in the dementia induced by mCRP. Therefore, locally deposited mCRP in the infarcted brain may be a novel biomarker for AD prognosis, and its antibody blockade opens up therapeutic opportunities for reducing post-stroke AD risk.

Effect of Memantine Hydrochloride on Homocysteine Level and Cognitive Function in Diabetic Vascular Dementia Model Mice

Increased Hcy has a toxic effect on nerve cells and can cause hippocampal death and directly damage the body’s cognitive function and memory ability, leading to the occurrence of vascular dementia. Hcy predicts vascular disease and might be a basis for clinical judgment. This article provides a new basis for the prevention and treatment of this disease by exploring the mechanism of action of memantine hydrochloride in diabetic vascular dementia. After grouping, mice walked through the Morris water maze to record the escape latency, and measured the Hcy level of the mice by high performance liquid chromatography. Observing the volume of brain atrophy in mice. GFAPT, APP, and CHAT level in mouse hippocampus was assessed by IHC and CHAT mRNA was detected by RT-PCR. Escape latency, Hcy level (11.46 ±0.74) yiimmol/L, brain atrophy volume (25.21 ±1.21) mm3, number of APP positive cells (46.7003±3.2431), number of GFAP positive cells (21.4000 ± 1.8127) were all significantly lower than those of model group. The positive rate of CHAT and the amount of CHAT mRNA in the memantine hydrochloride group was significantly elevated (P &lt; 0.05) with higher CHAT mRNA than model group and lower than blank group (P &lt; 0.05). Memantine hydrochloride could reduce the level of Hcy in mice, improve the cognitive function of mice with diabetic vascular dementia by improving the number of GFAP and CHAT positive cells in hippocampus and cortex, and increasing the amount of CHAT mRNA in brain tissue.

Central administration of afzelin extracted from Ribes fasciculatum improves cognitive and memory function in a mouse model of dementia

Neurodegenerative disorders are characterized by the decline of cognitive function and the progressive loss of memory. The dysfunctions of the cognitive and memory system are closely related to the decreases in brain-derived neurotrophic factor (BDNF) and cAMP response element-binding protein (CREB) signalings. Ribes fasciculatum, a medicinal plant grown in diverse countries, has been reported to pharmacological effects for autoimmune diseases and aging recently. Here we found that afzelin is a major compound in Ribes fasciculatum. To further examine its neuroprotective effect, the afzelin (100 ng/µl, three times a week) was administered into the third ventricle of the hypothalamus of C57BL/6 mice for one month and scopolamine was injected (i.p.) to these mice to impair cognition and memory before each behavior experiment. The electrophysiology to measure long-term potentiation and behavior tests for cognitive and memory functions were performed followed by investigating related molecular signaling pathways. Chronic administration of afzelin into the brain ameliorated synaptic plasticity and cognitive/memory behaviors in mice given scopolamine. Studies of mice’s hippocampi revealed that the response of afzelin was accountable for the restoration of the cholinergic systems and molecular signal transduction via CREB-BDNF pathways. In conclusion, the central administration of afzelin leads to improved neurocognitive and neuroprotective effects on synaptic plasticity and behaviors partly through the increase in CREB-BDNF signaling.

Dementia model mice exhibited improvements of neuropsychiatric symptoms as well as cognitive dysfunction with neural cell transplantation.

Elderly patients with dementia suffer from cognitive dysfunctions and neuropsychiatric symptoms (NPS) such as anxiety and depression. Alzheimer’s disease (AD) is a form of age-related dementia, and loss of cholinergic neurons is intimately associated with development of AD symptoms. We and others have reported that neural cell transplantation ameliorated cognitive dysfunction in AD model mice. It remains largely unclear whether neural cell transplantation ameliorates the NPS of AD. It would be interesting to determine whether NPS correlates with cognitive dysfunctions before and after neural cell transplantation in AD model mice. Based on the revalidation of our previous data from a Morris water maze test, we found that neural cell transplantation improved anxiety and depression significantly and marginally affected locomotion activity in AD mice. A correlation analysis revealed that the spatial learning function of AD mice was correlated with their NPS scores both before and after cell transplantation in a similar manner. In contrast, in the mice subjected to cell transplantation, spatial reference memory function was not correlated with NPS scores. These results suggested the neural cell transplantation in the AD model mice significantly improved NPS to the same degree as cognitive dysfunctions, possibly via distinct mechanisms, such as the cholinergic and GABAergic systems.

Dietary Protein Source Influences Brain Inflammation and Memory in a Male Senescence-Accelerated Mouse Model of Dementia.

Dementia is a pathological condition characterized by a decline in memory, as well as in other cognitive and social functions. The cellular and molecular mechanisms of brain damage in dementia are not completely understood; however, neuroinflammation is involved. Evidence suggests that chronic inflammation may impair cognitive performance and that dietary protein source may differentially influence this process. Dietary protein source has previously been shown to modify systemic inflammation in mouse models. Thus, we aimed to investigate the effect of chronic dietary protein source substitution in an ageing and dementia male mouse model, the senescence-accelerated mouse-prone 8 (SAMP8) model. We observed that dietary protein source differentially modified memory as shown by inhibitory avoidance testing at 4 months of age. Also, dietary protein source differentially modified neuroinflammation and gliosis in male SAMP8 mice. Our results suggest that chronic dietary protein source substitution may influence brain ageing and memory-related mechanisms in male SAMP8 mice. Moreover, the choice of dietary protein source in mouse diets for experimental purposes may need to be carefully considered when interpreting results.

Autophagic activity of piperine on small intestine in dementia model mice with Parkinson's disease

This article is to investigate the effect of piperine on the small intestine of mice with Parkinson's disease with dementia(PDD). Ninety-six C57 BL/6 mice of SPF grade were randomly divided into 8 groups(male, 12 in each group): normal group, model group, autophagy inhibitor group(6-amino-3-methylpurine, 3 MA, 30 mg·kg~(-1)), autophagy activator group(rapamycin, 1 mg·kg~(-1)), low, medium, and high dose piperine groups(10, 20, 40 mg·kg~(-1)), and medopar group(112.5 mg·kg~(-1)). Except for the normal group, mice in each group were injected subcutaneously with reserpine(0.1 mg·kg~(-1)) once every 48 hours for 40 days. In addition, on the 20 th day of administration, except for the normal group, the mice in the other groups were subjected to bilateral common carotid artery occlusion to finally prepare PDD models. At the same time, each group was given the corresponding drug treatment once a day for 40 days. After the last administration, the behavioral changes of mice were observed by autonomic activity experiment and hot plate experiment. The expression levels of α-synuclein(α-syn) and tyrosine hydroxylase(TH) in the small intestine were detected by immunohistochemistry. The expression levels of beclin-1, microtubule-associated protein 1 light chain 3 B(LC3 B) and p62 in the small intestine were detected by immunofluorescence assay. Hematoxylin-eosin staining was used to observe the pathological morphology of small intestine tissues in each group. Enzyme-linked immunosorbent assay was adopted for detection of β-amyloid precursor protein(APP), p-tau, acetylcholine transferase(ChAT), interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) in small intestine. Real-time fluorescent quantitative polymerase chain reaction was used to detect the expression of α-syn, TH, beclin-1, microtubule-associated protein 1 light chain 3(LC3), and p62 mRNA and mmu-miR-99 a-5 p in the small intestine. The results of this study showed that, as compared with the model group, the number of activities, the expression levels of ChAT, TH, and p62 were significantly increased in the 3 MA group, the various piperine dose groups, and the medopar group(P&lt;0.05), and their first foot licking time was shortened; APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were significantly reduced(P&lt;0.05). However, as compared with the model group, the number of activities, ChAT, TH, and p62 expression levels in the rapamycin group were significantly reduced(P&lt;0.05), and the APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were significantly increased(P&lt;0.05). As compared with the 3 MA group, the number of activities, ChAT, TH, and p62 expression levels were significantly reduced in the low and medium dose piperine groups and rapamycin group(P&lt;0.05); howe-ver, their first foot licking time was significantly prolonged, APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were increased significantly(P&lt;0.05). As compared with the medopar group, the number of activities, ChAT, TH, and p62 expression levels were significantly reduced in low dose piperine group and rapamycin group(P&lt;0.05), but their first foot licking time was significantly extended, and APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were significantly increased(P&lt;0.05). In addition, as compared with the normal group, the small intestinal epithelial cells of the model group and the rapamycin group were shed off a lot, with severe damages of intestinal mucosa as well as edema and shedding of the small intestine villi. After administration of the therapeutic interventions, the small intestinal epithelial cells of the 3 MA group, each dose group of piperine, and the medopa group were slightly damaged and the villi were slightly shed off. In summary, piperine has a protective effect on the small intestine of PDD model mice, showing reduced expression of mmu-miR-99 a-5 p, pro-inflammatory factors and autophagy factors, and the mechanism of slowing PDD pathological symptoms may be related to the inhibition of autophagy.

Improvement of glymphatic\u2013lymphatic drainage of beta-amyloid by focused ultrasound in Alzheimer\u2019s disease model

Drainage of parenchymal waste through the lymphatic system maintains brain homeostasis. Age-related changes of glymphatic–lymphatic clearance lead to the accumulation beta-amyloid (Aβ) in dementia models. In this study, focused ultrasound treatment in combination with microbubbles (FUS-MB) improved Aβ drainage in early dementia model mice, 5XFAD. FUS-MB enhanced solute Aβ clearance from brain, but not plaques, to cerebrospinal fluid (CSF) space and then deep cervical lymph node (dCLN). dCLN ligation exaggerated memory impairment and progress of plaque formation and also the beneficial effects of FUS-MB upon Aβ removal through CSF-lymphatic routes. In this ligation model, FUS-MB improved memory despite accumulation of Aβ in CSF. In conclusion, FUS-MB enhances glymphatic–lymphatic clearance of Aβ mainly by increasing brain-to-CSF Aβ drainage. We suggest that FUS-MB can delay dementia progress in early period and benefits of FUS-MB depend on the effect of Aβ disposal through CSF-lymphatics.