OBJECTIVE: To observe the effects of electroacupuncture (EA) at "Shenting" (GV24) and "Baihui" (GV20) on mitochondrial autophagy in hippocampal neurons and silent information regulator sirtuin 1 (Sirt1)/forkhead box O3 (FOXO3)/PTEN-inducible kinase 1 (PINK1)/Parkin pathway in rats with learning-memory impairment after cerebral ischemia reperfusion injury. METHODS: A total of 35 male SD rats were randomly divided into a sham operation group (9 rats) and a modeling group (26 rats). In the modeling group, middle cerebral artery occlusion method was used to establish the middle cerebral artery ischemia-reperfusion (MCAO/R) model, and 18 rats of successful modeling were randomly divided into a model group and an EA group, 9 rats in each one. EA was applied at "Shenting" (GV24) and "Baihui" (GV20) in the EA group, 30 min a time, once a day for 14 days. After modeling and on 7th and 14th days of intervention, neurologic deficit score was observed; the learning-memory ability was detected by Morris water maze test; the morphology of neurons in CA1 area of hippocampus was detected by Nissl staining; the mitochondrial morphology was observed by transmission electron microscopy; the protein expression of Beclin-1, microtubule-associated protein 1 light chain 3B (LC3B), P62, Sitrt1, FOXO3, PINK1 and Parkin was detected by Western blot. RESULTS: After modeling, the neurologic deficit scores in the model group and the EA group were higher than that in the sham operation group (P<0.001); on 7th and 14th days of intervention, the neurologic deficit scores in the model group were higher than those in the sham operation group (P<0.001), the neurologic deficit scores in the EA group were lower than those in the model group (P<0.05, P<0.01). After modeling, the escape latency in the model group and the EA group was prolonged compared with that in the sham operation group (P<0.001); on 9th-13th days of intervention, the escape latency in the model group was prolonged compared with that in the sham operation group (P<0.001), the escape latency in the EA group was shortened compared with that in the model group (P<0.05, P<0.01, P<0.001). The number of crossing plateau in the model group was less than that in the sham operation group (P<0.001); the number of crossing plateau in the EA group was more than that in the model group (P<0.05). In the model group, in CA1 area of hippocampus, the number of neurons was less, with sparse arrangement, nuclear fixation, deep cytoplasmic staining, and reduction of Nissl substance; the morphology of mitochondrion was swollen, membrane structure was fragmented, and autophagic lysosomes were formed. Compared with the model group, in the EA group, in CA1 area of hippocampus, the number of neurons was increased, the number of cells of abnormal morphology was decreased, and the number of Nissl substance was increased; the morphology of mitochondrion was more intact and the number of autophagic lysosomes was increased. Compared with the sham operation group, in the model group, the protein expression of Beclin-1, FOXO3, PINK1, Parkin and the LC3BⅡ/Ⅰ ratio in hippocampus were increased (P<0.01, P<0.001), while the protein expression of P62 was decreased (P<0.05). Compared with the model group, in the EA group, the protein expression of Beclin-1, Sirt1, FOXO3, PINK1, Parkin and the LC3BⅡ/Ⅰratio in hippocampus were increased (P<0.001, P<0.01), while the protein expression of P62 was decreased (P<0.001). CONCLUSION EA at "Shenting" (GV24) and "Baihui" (GV20) can relieve the symptoms of neurological deficits and improve the learning-memory ability in MCAO/R rats, its mechanism may relate to the modulation of Sirt1/FOXO3/PINK1/Parkin pathway and the enhancement of mitochondrial autophagy.
Animals ; Electroacupuncture ; Male ; Rats, Sprague-Dawley ; Rats ; Forkhead Box Protein O3/genetics* ; Reperfusion Injury/metabolism* ; Ubiquitin-Protein Ligases/genetics* ; Brain Ischemia/complications* ; Mitochondria/genetics* ; Autophagy ; Protein Kinases/genetics* ; Sirtuin 1/genetics* ; Humans ; Memory Disorders/psychology* ; Signal Transduction

OBJECTIVES: To explore the correlation of hypertension with postoperative cognitive dysfunction and its possible mechanism. METHODS: Twelve-week-old spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats were both randomized into control group and surgical group (n=8). In the latter group, the rats received carotid artery exposure surgery under sevoflurane anesthesia to establish models of postoperative learning and memory impairment. Postoperative cognitive function changes of the rats were evaluated using behavioral tests. The hippocampus of the rats were collected for determining ATP level and mitochondrial membrane potential (MMP) and for detecting expressions of UCP2 and astrocyte markers (GFAP and NOX4) using Western blotting and immunofluorescence staining. Serum levels of ROS, IL-6, IL-1β and TNF‑α were detected using ELISA. Nissl staining was used to examine hippocampal neuronal loss in the CA1 region. RESULTS: The SHRs exhibited exacerbated learning and memory deficits following the surgery as shown by significantly reduced performance in novel object recognition tests and context-related and tone-related fear conditioning experiments. Compared with WKY rats, the SHRs had significantly decreased mitochondrial UCP2 expression and MMP in the hippocampus, increased hippocampal ATP level, and markedly increased serum levels of ROS and inflammatory factors, showing also increased activation of hippocampal astrocytes and microglia and reduced number of neurons positive for Nissl staining. CONCLUSIONS Hypertension can exacerbate major postoperative learning and memory impairment in rats possibly as a result of UCP2-mediated mitochondrial dysfunction and oxidative stress damage, which further leads to astrocyte overactivation and neuronal damage.
Animals ; Rats, Inbred SHR ; Rats ; Uncoupling Protein 2 ; Rats, Inbred WKY ; Hypertension/physiopathology* ; Hippocampus/metabolism* ; Mitochondria/metabolism* ; Down-Regulation ; Male ; Memory Disorders/etiology* ; Mitochondrial Proteins/metabolism*

Early-life stress (ES) leads to cognitive dysfunction in female adolescents, but the underlying neural mechanisms remain elusive. Recent evidence suggests that the cell adhesion molecules NECTIN1 and NECTIN3 play a role in cognition and ES-related cognitive deficits in male rodents. In this study, we aimed to investigate whether and how nectins contribute to ES-induced cognitive dysfunction in female adolescents. Applying the well-established limited bedding and nesting material paradigm, we found that ES impairs recognition memory, suppresses prefrontal NECTIN1 and hippocampal NECTIN3 expression, and upregulates corticotropin-releasing hormone (Crh) and its receptor 1 (Crhr1) mRNA levels in the hippocampus of adolescent female mice. Genetic experiments revealed that the reduction of dorsal CA1 (dCA1) NECTIN3 mediates ES-induced object recognition memory deficits, as knocking down dCA1 NECTIN3 impaired animals' performance in the novel object recognition task, while overexpression of dCA1 NECTIN3 successfully reversed the ES-induced deficits. Notably, prefrontal NECTIN1 knockdown did not result in significant cognitive impairments. Furthermore, acute systemic administration of antalarmin, a CRHR1 antagonist, upregulated hippocampal NECTIN3 levels and rescued object and spatial memory deficits in stressed mice. Our findings underscore the critical role of dCA1 NECTIN3 in mediating ES-induced object recognition memory deficits in adolescent female mice, highlighting it as a potential therapeutic target for stress-related psychiatric disorders in women.
Animals ; Female ; Mice ; CA1 Region, Hippocampal/metabolism* ; Cell Adhesion Molecules/metabolism* ; CRF Receptor, Type 1/metabolism* ; Memory Disorders/etiology* ; Mice, Inbred C57BL ; Nectins/genetics* ; Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors* ; Recognition, Psychology/physiology* ; Stress, Psychological/complications*

Alzheimer's disease (AD), a neurodegenerative disorder with complex etiologies, manifests through a cascade of pathological changes before clinical symptoms become apparent. Among these early changes, alterations in the expression of non-coding RNAs (ncRNAs) have emerged as pivotal events. In this study, we focused on the aberrant expression of ncRNAs and revealed that Lamr1-ps1, a pseudogene of the laminin receptor, significantly exacerbates early spatial learning and memory deficits in APP/PS1 mice. Through a combination of bioinformatics prediction and experimental validation, we identified the miR-29c/Bace1 pathway as a potential regulatory mechanism by which Lamr1-ps1 influences AD pathology. Importantly, augmenting the miR-29c-3p levels in mice ameliorated memory deficits, underscoring the therapeutic potential of targeting miR-29c-3p in early AD intervention. This study not only provides new insights into the role of pseudogenes in AD but also consolidates a foundational basis for considering miR-29c as a viable therapeutic target, offering a novel avenue for AD research and treatment strategies.
Animals ; Alzheimer Disease/pathology* ; Pseudogenes/genetics* ; Mice ; Memory Disorders/metabolism* ; MicroRNAs/genetics* ; Disease Models, Animal ; Spatial Learning/physiology* ; Mice, Transgenic ; Presenilin-1/genetics* ; Male ; Amyloid Precursor Protein Secretases/metabolism* ; Mice, Inbred C57BL ; Aspartic Acid Endopeptidases/metabolism*

Vascular damage plays a significant role in the onset and progression of Alzheimer's disease (AD). However, the precise molecular mechanisms underlying the induction of neuronal injury by vascular damage remain unclear. The present study aimed to examine the impact of fibrinogen (Fg) on tau pathology. The results showed that Fg deposits in the brains of tau P301S transgenic mice interact with tau, enhancing the cytotoxicity of pathological tau aggregates and promoting tau phosphorylation and aggregation. Notably, Fg-modified tau fibrils caused enhanced neuronal apoptosis and synaptic damage compared to unmodified fibrils. Furthermore, intrahippocampal injection of Fg-modified tau fibrils worsened the tau pathology, neuroinflammation, synaptic damage, neuronal apoptosis, and cognitive dysfunction in tau P301S mice compared to controls. The present study provides compelling evidence linking Fg and tau, thereby connecting cerebrovascular damage to tau pathology in AD. Consequently, inhibiting Fg-mediated tau pathology could potentially impede the progression of AD.
Animals ; tau Proteins/metabolism* ; Alzheimer Disease/metabolism* ; Fibrinogen/metabolism* ; Mice, Transgenic ; Mice ; Disease Models, Animal ; Memory Disorders/metabolism* ; Male ; Mice, Inbred C57BL ; Brain/metabolism* ; Hippocampus/metabolism* ; Protein Aggregation, Pathological/metabolism* ; Apoptosis ; Phosphorylation

OBJECTIVE: To explore the mechanism of electroacupuncture (EA) at "Fengchi" (GB 20) and "Sishencong" (EX-HN 1) on learning and memory impairment in vascular dementia (VD) rats by observing the influences on the N-methyl-D-aspartate receptor (NMDAR)/cyclic adenosine monophosphate response element-binding protein (CREB)/brain-derived neurotrophic factor (BDNF) signaling pathway and the excitotoxicity induced by hippocampal calcium overload. METHODS: Thirty-two male SD rats of SPF grade were selected and randomized into a normal group (6 rats), a sham-operation group (6 rats) and an operation group (20 rats). VD model was established with the modified Pulsinelli's four-vessel occlusion (4-VO) method. Twelve rats after successfully modeled were assigned randomly into a model group and an EA group, 6 rats in each one. In the EA group, EA was delivered at bilateral "Fengchi" (GB 20) and "Sishencong" (EX-HN 1), with the continuous wave, the frequency of 2 Hz and the electric current of 1 mA. Stimulation intensity was adjusted depending on the slightly trembling of rat head. EA was given once daily, 30 min each time; and EA intervention was delivered for 21 days continuously. Using Morris water maze test, the learning and memory function was assessed. The neuronal morphology in the hippocampal CA1 was observed with HE staining; the level of glutamate (GLU) in serum and hippocampal tissue, as well as the activity of calcium pump (Ca²⁺-ATP) in the hippocampus were detected using colorimetric method. The protein expression of NMDAR, calmodulin-dependent protein kinase Ⅱ (CaMKⅡ), phosphorylated calmodulin-dependent protein kinase Ⅱ (p-CaMKⅡ), phosphorylated cyclic phosphoradenosine effector element binding proteins (p-CREB), CREB, and BDNF in the hippocampal CA1 was detected using immunohistochemistry. The protein expression of NMDAR, CREB, p-CREB and BDNF in the hippocampal tissue was detected using Western blot method. RESULTS: Compared to the sham-operation group, in the model group, the escape latency was prolonged and the platform crossing times of rats were reduced (P<0.01), the hippocampal neuron structure was damaged to different degrees, the structure in hippocampal CA1 was loosened, the arrangement disorganized, with clear grid-like structure; the neuronal morphology was irregular, pyknosis and even dissolution occurred, glial cells increased, blood capillary was dilated and the inflammatory cells were infiltrated and scattered. The level of GLU in the serum and hippocampal tissue and the protein expression of hippocampal NMDAR were elevated (P<0.01), the activity of Ca²⁺-ATP and the protein expression of CaMKⅡ, p-CaMKⅡ, CREB, p-CREB and BDNF were reduced (P<0.01, P<0.05); and the ratio of p-CaMKⅡ/CaMKⅡ and that of p-CREB/CREB were dropped (P<0.05). In comparison with the model group, in the EA group, the escape latency was shortened and the platform crossing times of rats rose (P<0.01), the arrangement was improved in the hippocampal CA1, the neuronal morphology was intact, the nucleoli were clear relatively and the pyknosis or dissolution were attenuated, the numbers of glial cells reduced relatively, the dilation of blood capillary was alleviated. The level of GLU in the serum and hippocampal tissue and the protein expression of NMDAR were reduced in the hippocampal tissue (P<0.01), the activity of Ca²⁺-ATP and the protein expression of CaMKⅡ, p-CaMKⅡ, CREB, p-CREB and BDNF were elevated (P<0.05, P<0.01); and the ratio of p-CaMKⅡ/CaMKⅡ and that of p-CREB/CREB increased (P<0.05). CONCLUSION EA at "Fengchi" (GB 20) and "Sishencong" (EX-HN 1) can attenuate learning and memory impairment in VD rats, which may be obtained by reducing GLU level in hippocampal tissue, inhibiting hippocampal excitotoxicity, mediating protein expression related to the NMDAR/CREB/BDNF signaling pathway, and maintaining neuronal survival and growth.
Electroacupuncture ; Male ; Animals ; Rats, Sprague-Dawley ; Learning ; Memory ; Signal Transduction ; Cyclic AMP Response Element-Binding Protein/metabolism* ; Memory Disorders/therapy* ; Brain-Derived Neurotrophic Factor/metabolism* ; Receptors, N-Methyl-D-Aspartate/metabolism* ; Dementia, Vascular/therapy*

OBJECTIVE: Exposure to high intensity, low frequency noise (HI-LFN) causes vibroacoustic disease (VAD), with memory deficit as a primary non-auditory symptomatic effect of VAD. However, the underlying mechanism of the memory deficit is unknown. This study aimed to characterize potential mechanisms involving morphological changes of neurons and nerve fibers in the hippocampus, after exposure to HI-LFN. METHODS: Adult wild-type and transient receptor potential vanilloid subtype 4 knockout (TRPV4^-/-) mice were used for construction of the HI-LFN injury model. The new object recognition task and the Morris water maze test were used to measure the memory of these animals. Hemoxylin and eosin and immunofluorescence staining were used to examine morphological changes of the hippocampus after exposure to HI-LFN. RESULTS: The expression of TRPV4 was significantly upregulated in the hippocampus after HI-LFN exposure. Furthermore, memory deficits correlated with lower densities of neurons and neurofilament-positive nerve fibers in the cornu ammonis 1 (CA1) and dentate gyrus (DG) hippocampal areas in wild-type mice. However, TRPV4^-/- mice showed better performance in memory tests and more integrated neurofilament-positive nerve fibers in the CA1 and DG areas after HI-LFN exposure. CONCLUSION TRPV4 up-regulation induced neurofilament positive nerve fiber injury in the hippocampus, which was a possible mechanism for memory impairment and cognitive decline resulting from HI-LFN exposure. Together, these results identified a promising therapeutic target for treating cognitive dysfunction in VAD patients.
Animals ; Mice ; TRPV Cation Channels/metabolism* ; Intermediate Filaments/metabolism* ; Hippocampus/metabolism* ; Neurons/metabolism* ; Memory Disorders/metabolism*

Mice ; Animals ; Alzheimer Disease/complications* ; Entorhinal Cortex/metabolism* ; Brain-Derived Neurotrophic Factor/metabolism* ; Memory Disorders/etiology* ; Thalamus/metabolism* ; Disease Models, Animal

Objective: The hippocampus is thought to be a vulnerable target of microwave exposure. The aim of the present study was to investigate whether 20-hydroxyecdysone (20E) acted as a fate regulator of adult rat hippocampal neural stem cells (NSCs). Furthermore, we investigated if 20E attenuated high power microwave (HMP) radiation-induced learning and memory deficits. Methods: Sixty male Sprague-Dawley rats were randomly divided into three groups: normal controls, radiation treated, and radiation+20E treated. Rats in the radiation and radiation+20E treatment groups were exposed to HPM radiation from a microwave emission system. The learning and memory abilities of the rats were assessed using the Morris water maze test. Primary adult rat hippocampal NSCs were isolated in vitro and cultured to evaluate their proliferation and differentiation. In addition, hematoxylin & eosin staining, western blotting, and immunofluorescence were used to detect changes in the rat brain and the proliferation and differentiation of the adult rat hippocampal NSCs after HPM radiation exposure. Results: The results showed that 20E induced neuronal differentiation of adult hippocampal NSCs from HPM radiation-exposed rats via the Wnt3a/β-catenin signaling pathway in vitro. Furthermore, 20E facilitated neurogenesis in the subgranular zone of the rat brain following HPM radiation exposure. Administration of 20E attenuated learning and memory deficits in HPM radiation-exposed rats and frizzled-related protein (FRZB) reduced the 20E-induced nuclear translocation of β-catenin, while FRZB treatment also reversed 20E-induced neuronal differentiation of NSCs in vitro. Conclusion These results suggested that 20E was a fate regulator of adult rat hippocampal NSCs, where it played a role in attenuating HPM radiation-induced learning and memory deficits.
Animals ; Cell Proliferation ; Ecdysterone/pharmacology* ; Hippocampus/metabolism* ; Male ; Memory Disorders ; Microwaves ; Neural Stem Cells/physiology* ; Rats ; Rats, Sprague-Dawley ; beta Catenin/metabolism*

BACKGROUND: Prenatal stress can cause neurobiological and behavioral defects in offspring; environmental factors play a crucial role in regulating the development of brain and behavioral; this study was designed to test and verify whether an enriched environment can repair learning and memory impairment in offspring rats induced by prenatal stress and to explore its mechanism involving the expression of insulin-like growth factor-2 (IGF-2) and activity-regulated cytoskeletal-associated protein (Arc) in the hippocampus of the offspring. METHODS: Rats were selected to establish a chronic unpredictable mild stress (CUMS) model during pregnancy. Offspring were weaned on 21st day and housed under either standard or an enriched environment. The learning and memory ability were tested using Morris water maze and Y-maze. The expression of IGF-2 and Arc mRNA and protein were respectively measured by using RT-PCR and Western blotting. RESULTS: There was an elevation in the plasma corticosterone level of rat model of maternal chronic stress during pregnancy. Maternal stress's offspring exposed to an enriched environment could decrease their plasma corticosterone level and improve their weight. The offspring of maternal stress during pregnancy exhibited abnormalities in Morris water maze and Y-maze, which were improved in an enriched environment. The expression of IGF-2, Arc mRNA, and protein in offspring of maternal stress during pregnancy was boosted and some relationships existed between these parameters after being exposed enriched environment. CONCLUSIONS The learning and memory impairment in offspring of prenatal stress can be rectified by the enriched environment, the mechanism of which is related to the decreasing plasma corticosterone and increasing hippocampal IGF-2 and Arc of offspring rats following maternal chronic stress during pregnancy.
Animals ; Cytoskeletal Proteins/metabolism* ; Female ; Gene Expression Regulation ; Hippocampus/metabolism* ; Insulin-Like Growth Factor II/metabolism* ; Learning ; Learning Disabilities/psychology* ; Male ; Memory Disorders/psychology* ; Nerve Tissue Proteins/metabolism* ; Pregnancy ; Prenatal Exposure Delayed Effects/psychology* ; Random Allocation ; Rats ; Rats, Wistar ; Social Environment ; Stress, Psychological/genetics*