scholarly journals Pathological and non-pathological aging, SAMP8 and SAMR1. What do hippocampal neuronal populations tell us?

2019 ◽  
Author(s):  
MJ Lagartos-Donate ◽  
J Gonzáles-Fuentes ◽  
P Marcos-Rabal ◽  
R Insausti ◽  
MM Arroyo-Jiménez
Keyword(s):  
Learning And Memory ◽  
Hippocampal Formation ◽  
Neurological Diseases ◽  
Accelerated Aging ◽  
Neural Population ◽  
Neuronal Populations ◽  
Pathological Aging ◽  
Local Circuitry ◽  
Samp8 Mice ◽  
Senescence Accelerated Mouse

ABSTRACTAlterations of cognitive processes and memory are one of the most important manifestations related to aging. However, not all memory types are affected in the same way. Learning and spatial memory are susceptible to these changes. The hippocampus represents the anatomical substrate of this type of memory, affected by structural and functional alterations along the normal aging and neurological diseases such as Alzheimer’s disease, Parkinson’s, schizophrenia and epilepsy. Some of the alterations related to aging are associated with alterations in the hippocampal interneuron populations and with an increase in excitability in the hippocampal circuit.In order to understand better the underlying processes in normal and pathological aging mechanisms, a murine model (Senescence-Accelerated Mouse Prone, SAMP8) and its respective controls (Senescence-Accelerated Mouse Resistant, SAMR1) have been used. While SAMP8 is a naturally occurring mouse line that displays a phenotype of accelerated aging with learning and memory impairment and these changes of learning and memory might be linked to some alterations in neuronal populations of the hippocampus. Thus, we analyzed the distribution and density of PV, CR and STT interneurons in the hippocampus of young and old mice as well as possible morphological and cholinergic changes in hippocampal formation. Comparing SAMR1 and SAMP8 we did not find any neural population that was specifically affected by aging in both groups. Interestingly, CR immunoreactivity and STT immunoreactivity showed changes in SAMP8 mice when they were compared to their controls. In SAMP8 CR+ and STT+ neurons decreased significantly along aging which suggests that CR and STT interneurons play a more important role than PV neurons in the pathological aging of the brain. In the case of SAMP8 mice the neural changes might be related to changes of the cholinergic system that might be affecting the wiring into the hippocampus formation through the perforant pathway. Further studies of this local circuitry will help to comprehend better how different inputs into these neural populations of the hippocampus could be affecting the development of neurodegerative diseases.

scholarly journals Icaritin Improves Memory and Learning Ability by Decreasing BACE-1 Expression and the Bax/Bcl-2 Ratio in Senescence-Accelerated Mouse Prone 8 (SAMP8) Mice

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yuan-Yuan Li ◽  
Nan-Qu Huang ◽  
Fei Feng ◽  
Ying Li ◽  
Xiu-Mei Luo ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Chinese Herb ◽  
Treated Group ◽  
Learning Ability ◽  
Control Group ◽  
Spatial Learning And Memory ◽  
Therapeutic Benefits ◽  
Samp8 Mice ◽  
Senescence Accelerated Mouse ◽  
Bace 1

Icaritin (ICT) is the main component in the traditional Chinese herb Epimedium, and it has been shown to have anti-Alzheimer’s disease (AD) effects, but its neuroprotective effects and the pharmacological mechanisms are unclear. In the present study, senescence-accelerated mouse prone 8 (SAMP8) mice were randomly divided into a model group and an ICT-treated group. Learning and memory abilities were detected by the Morris water maze assay, and the expression of amyloid beta protein (Aβ) and β-site APP cleavage enzyme 1 (BACE1) was determined by Western blotting and polymerase chain reaction (PCR). Histological changes in CA1 and CA3 were detected by hematoxylin-eosin staining (H&E staining), and the immunohistochemical analysis was used to detect the expression and localization of Bax and Bcl-2. The results showed that compared with the SAMP8 mice, the ICT-treated SAMP8 mice showed improvements in spatial learning and memory retention. In addition, the number of necrotic cells and the morphological changes in CA1 and CA3 areas were significantly alleviated in the group of ICT-treated SAMP8 mice, and the expression of BACE1, Aβ1-42 levels, and the Bax/Bcl-2 ratio in the hippocampus was obviously decreased in the ICT-treated group compared with the control group. The results demonstrated that ICT reduced BACE-1 levels, the contents of Aβ1-42, and the Bax/Bcl-2 ratio, suggesting that ICT might have potential therapeutic benefits by delaying or modifying the progression of AD.

scholarly journals Anredera cordifolia extract enhances learning and memory in senescence-accelerated mouse-prone 8 (SAMP8) mice

2021 ◽  
Author(s):  
Eri Sumiyoshi ◽  
Michio Hashimoto ◽  
Shahdat Hossain ◽  
Kentaro Matsuzaki ◽  
Rafiad Islam ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Samp8 Mice ◽  
Senescence Accelerated Mouse

Anredera cordifolia extract increased learning and memory by enhancing levels of hippocampal BDNF, PSD95, NR2A, and p-CREB in SAMP8 mice.

scholarly journals Microalgae Aurantiochytrium Sp. Increases Neurogenesis and Improves Spatial Learning and Memory in Senescence-Accelerated Mouse-Prone 8 Mice

2021 ◽  
Vol 8 ◽  
Author(s):  
Kazunori Sasaki ◽  
Noelia Geribaldi-Doldán ◽  
Qingqing Wu ◽  
Julie Davies ◽  
Francis G. Szele ◽  
...  
Keyword(s):  
Stem Cells ◽  
Learning And Memory ◽  
Morris Water Maze ◽  
Spatial Learning ◽  
Water Maze ◽  
Amyloid Β ◽  
Spatial Learning And Memory ◽  
And Function ◽  
Samp8 Mice ◽  
Senescence Accelerated Mouse

Much attention has recently been focused on nutraceuticals, with minimal adverse effects, developed for preventing or treating neurological diseases such as Alzheimer's disease (AD). The present study was conducted to investigate the potential effect on neural development and function of the microalgae Aurantiochytrium sp. as a nutraceutical. To test neuroprotection by the ethanol extract of Aurantiochytrium (EEA) and a derivative, the n-Hexane layer of EEA (HEEA), amyloid-β-stimulated SH-SY5Y cells, was used as an in vitro AD model. We then assessed the potential enhancement of neurogenesis by EEA and HEEA using murine ex vivo neurospheres. We also administered EEA or HEEA to senescence-accelerated mouse-prone 8 (SAMP8) mice, a non-transgenic strain with accelerated aging and AD-like memory loss for evaluation of spatial learning and memory using the Morris water maze test. Finally, we performed immunohistochemical analysis for assessment of neurogenesis in mice administered EEA. Pretreatment of SH-SY5Y cells with EEA or the squalene-rich fraction of EEA, HEEA, ameliorated amyloid-β-induced cytotoxicity. Interestingly, only EEA-treated cells showed a significant increase in cell metabolism and intracellular adenosine triphosphate production. Moreover, EEA treatment significantly increased the number of neurospheres, whereas HEEA treatment significantly increased the number of β-III-tubulin+ young neurons and GFAP+ astrocytes. SAMP8 mice were given 50 mg/kg EEA or HEEA orally for 30 days. EEA and HEEA decreased escape latency in the Morris water maze in SAMP8 mice, indicating improved memory. To detect stem cells and newborn neurons, we administered BrdU for 9 days and measured BrdU+ cells in the dentate gyrus, a neurogenic stem cell niche of the hippocampus. In SAMP8 mice, EEA rapidly and significantly increased the number of BrdU+GFAP+ stem cells and their progeny, BrdU+NeuN+ mature neurons. In conclusion, our data in aggregate indicate that EEA and its constituents could be developed into a nutraceutical for promoting brain health and function against several age-related diseases, particularly AD.

scholarly journals Hippocampal Sclerosis in Pilocarpine Epilepsy: Survival of Peptide-Containing Neurons and Learning and Memory Disturbances in the Adult NMRI Strain Mouse

2021 ◽  
Vol 23 (1) ◽  
pp. 204
Author(s):  
Adrienne Mátyás ◽  
Emőke Borbély ◽  
András Mihály
Keyword(s):  
Neuropeptide Y ◽  
Learning And Memory ◽  
Hippocampal Formation ◽  
Hippocampal Sclerosis ◽  
Neuronal Loss ◽  
Cell Counting ◽  
Barnes Maze ◽  
Memory Functions ◽  
Neuronal Populations ◽  
Immunohistochemical Methods

The present experiments reveal the alterations of the hippocampal neuronal populations in chronic epilepsy. The mice were injected with a single dose of pilocarpine. They had status epilepticus and spontaneously recurrent motor seizures. Three months after pilocarpine treatment, the animals were investigated with the Barnes maze to determine their learning and memory capabilities. Their hippocampi were analyzed 2 weeks later (at 3.5 months) with standard immunohistochemical methods and cell counting. Every animal displayed hippocampal sclerosis. The neuronal loss was evaluated with neuronal-N immunostaining, and the activation of the microglia was measured with Iba1 immunohistochemistry. The neuropeptide Y, parvalbumin, and calretinin immunoreactive structures were qualitatively and quantitatively analyzed in the hippocampal formation. The results were compared statistically to the results of the control mice. We detected neuronal loss and strongly activated microglia populations. Neuropeptide Y was significantly upregulated in the sprouting axons. The number of parvalbumin- and calretinin-containing interneurons decreased significantly in the Ammon’s horn and dentate gyrus. The epileptic animals displayed significantly worse learning and memory functions. We concluded that degeneration of the principal neurons, a numerical decrease of PV-containing GABAergic neurons, and strong peptidergic axonal sprouting were responsible for the loss of the hippocampal learning and memory functions.

scholarly journals Mechanism of anti-dementia effects of mangiferin in a senescence accelerated mouse (SAMP8) model

2019 ◽  
Vol 39 (9) ◽  
Author(s):  
Zhengcai Du ◽  
Fangcao Fanshi ◽  
Yu-Heng Lai ◽  
Jung-Ren Chen ◽  
Erwei Hao ◽  
...  
Keyword(s):  
Mouse Model ◽  
Learning And Memory ◽  
Hippocampal Neurons ◽  
Amyloid Β ◽  
Memory Retention ◽  
Samp8 Mouse ◽  
Mango Leaves ◽  
Samp8 Mice ◽  
The Brain ◽  
Senescence Accelerated Mouse

Abstract Mangiferin (2-β-d-glucopyranosyl-1,3,6,7-tetrahydroxy-9H-xanthen-9-one), a xanthanoid, is one of the major compounds isolated from mango leaves and bark fruit. Previous studies have identified several properties of mangiferin, such as preventing microbial growth, reducing oxidative stress and helping reduce risk of diabetes. The aim of the present study is to explore the potential anti-dementia effects of Mangiferin in a senescence-accelerated mouse prone 8 (SAMP8) mouse model. Morris water maze (MWM) test showed that mangiferin significantly improved the learning and memory retention in SAMP8 mice. In addition, mangiferin reduced the damage in hippocampal neurons and mitochondria, and decreased the expression of amyloid-β (Aβ1-40 and Aβ1-42); however, no influence on the expression of amyloid precursor protein (APP) within the brain of SAMP8 mice. Moreover, Mangiferin inhibited lipid peroxidation (LPO). In conclusion, we provided evidences to show that mangiferin significantly restored the learning and memory impairment in the SAMP8 mouse model, and reduced the pathological injury in hippocampal by modulating lipid oxidation and amyloid-β deposition in the brain.

scholarly journals Erinacine A-Enriched Hericium erinaceus Mycelium Delays Progression of Age-Related Cognitive Decline in Senescence Accelerated Mouse Prone 8 (SAMP8) Mice

Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3659
Author(s):  
Li-Ya Lee ◽  
Wayne Chou ◽  
Wan-Ping Chen ◽  
Ming-Fu Wang ◽  
Ying-Ju Chen ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Active Avoidance ◽  
Brain Aging ◽  
Cognitive Disability ◽  
Neuroprotective Effects ◽  
Hericium Erinaceus ◽  
Age Related ◽  
Erinacine A ◽  
Samp8 Mice ◽  
Senescence Accelerated Mouse

There have been many reports on the neuroprotective effects of Hericium erinaceus mycelium, in which the most well-known active compounds found are diterpenoids, such as erinacine A. Previously, erinacine A-enriched Hericeum erinaceus mycelium (EAHEM) was shown to decrease amyloid plaque aggregation and improve cognitive disability in Alzheimer’s disease model APP/PS1 mice. However, its effects on brain aging have not yet been touched upon. Here, we used senescence accelerated mouse prone 8 (SAMP8) mice as a model to elucidate the mechanism by which EAHEM delays the aging of the brain. Three-month-old SAMP8 mice were divided into three EAHEM dosage groups, administered at 108, 215 and 431 mg/kg/BW/day, respectively. During the 12th week of EAHEM feeding, learning and memory of the mice were evaluated by single-trial passive avoidance and active avoidance test. After sacrifice, the amyloid plaques, induced nitric oxidase synthase (iNOS) activity, thiobarbituric acid-reactive substances (TBARS) and 8-OHdG levels were analyzed. We found that the lowest dose of 108 mg/kg/BW EAHEM was sufficient to significantly improve learning and memory in the passive and active avoidance tests. In all three EAHEM dose groups, iNOS, TBARS and 8-OHdG levels all decreased significantly and showed a dose-dependent response. The results indicate that EAHEM improved learning and memory and delayed degenerative aging in mice brains.

The Effects of P75NTR on Learning Memory Mediated by Hippocampal Apoptosis and Synaptic Plasticity

2020 ◽  
Vol 26 ◽  
Author(s):  
Jun-Jie Tang ◽  
Shuang Feng ◽  
Xing-Dong Chen ◽  
Hua Huang ◽  
Min Mao ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Learning And Memory ◽  
Neurological Diseases ◽  
Neurotrophin Receptor ◽  
P75 Neurotrophin Receptor ◽  
Negative Effects ◽  
Apoptotic Effect ◽  
New Ideas ◽  
The Relationship

: Neurological diseases bring great mental and physical torture to the patients, and have long-term and sustained negative effects on families and society. The attention to neurological diseases is increasing, and the improvement of the material level is accompanied by an increase in the demand for mental level. The p75 neurotrophin receptor (p75NTR) is a low-affinity neurotrophin receptor and involved in diverse and pleiotropic effects in the developmental and adult central nervous system (CNS). Since neurological diseases are usually accompanied by the regression of memory, the pathogenesis of p75NTR also activates and inhibits other signaling pathways, which has a serious impact on the learning and memory of patients. The results of studies shown that p75NTR is associated with LTP/LTD-induced synaptic enhancement and inhibition, suggest that p75NTR may be involved in the progression of synaptic plasticity. And its pro-apoptotic effect is associated with activation of proBDNF and inhibition of proNGF, and TrkA/p75NTR imbalance leads to pro-survival or pro-apoptotic phenomena. It can be inferred that p75NTR mediates apoptosis in the hippocampus and amygdale, which may affect learning and memory behavior. This article mainly discusses the relationship between p75NTR and learning memory and associated mechanisms, which may provide some new ideas for the treatment of neurological diseases.

Postnatal Development of the Hippocampus in Male Albino Rats: A Histomorphometric Study

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
A A A Baraka ◽  
K A Hafez ◽  
A I A Othman ◽  
A M M Sadek
Keyword(s):  
Dentate Gyrus ◽  
Postnatal Development ◽  
Learning And Memory ◽  
Hippocampal Formation ◽  
Critical Role ◽  
Mammalian Brain ◽  
Albino Rats ◽  
Ammon's Horn ◽  
Hippocampus Proper ◽  
Ammon’S Horn

Abstract Introduction In recent year deterioration in cognitive, learning, and memory become one of the significant problems in human life. Hippocampus is a pivotal part of the brain’s limbic system which serves a critical role in memory, learning process and regulating the emotions. In most regions of the brain, neurons are generated only at specific periods of early development, and not born in the adulthood. In contrast, hippocampal neurons are generated throughout development and adult life. The hippocampal dentate gyrus was reported to be one of the few regions of the mammalian brain where neurogenesis continue to occur throughout adulthood. The neurogenesis in the dentate gyrus was thought to play an important role in hippocampus-dependent learning and memory. The hippocampal formation is composed of the hippocampus proper, the dentate gyrus and the subiculum. The hippocampus proper is the largest part and is subdivided into fields designated as Cornu Ammonis or Ammon’s horn (CA) from CA1 to CA4. Ammon's horn is continuous with the subiculum, which acts as the main output source of the hippocampal formation. Aim of the Study To study the postnatal development of the hippocampal formation. Materials and Methods Five male albino rats from the following postnatal ages day 1, week 1, week 2, week3 and week 4 were studied by histological, immunohistochemical, and morphometric methods. Results The general architecture of the hippocampus proper with its polymorphic, pyramidal, and molecular layers was present at day1, whereas the details of the adult structure appeared at week 2. In the dentate gyrus, distinct lamination appeared at week 1 and its maturation continued with the production of neurons at the interhilar zone that peaked at week 2. The number and density of pyramidal axons and dendrites increase by age. Astrocytes increased in size and staining affinity for glial filaments, and acquired a stellate shape with age. Furthermore, the number of granule cell layers increased concomitantly with the increase in thickness of the molecular and polymorphic layers of both the hippocampus proper and the dentate gyrus. Conclusion The important sequences of events in the growth and maturation of the hippocampal formation in male albino rat occurred in the first 2 postnatal weeks.

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