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1.
Biomédica (Bogotá) ; 42(1): 196-206, ene.-mar. 2022. graf
Article in Spanish | LILACS | ID: biblio-1374518

ABSTRACT

Introducción. Las lesiones del nervio facial afectan la plasticidad a largo plazo en el hipocampo, así como la memoria de reconocimiento de objetos y la memoria espacial, dos procesos dependientes de esta estructura. Si bien se ha descrito una activación de la microglía en la corteza motora primaria asociada con esta lesión, no se conoce si ocurre algo similar en el hipocampo. Objetivo. Caracterizar en ratas el efecto de la lesión unilateral del nervio facial sobre la activación de células de la microglía en el hipocampo contralateral. Materiales y métodos. Se hicieron experimentos de inmunohistoquímica para detectar células de la microglía en el hipocampo de ratas sometidas a lesión irreversible del nervio facial. Los animales se sacrificaron en distintos momentos después de la lesión, para evaluar la evolución de la proliferación (densidad de células) y la activación (área celular) de la microglía en el tejido del hipocampo. Los tejidos cerebrales de los animales de control se compararon con los de animales lesionados sacrificados en los días 1,3, 7, 21 y 35 después de la lesión. Resultados. Las células de la microglía en el hipocampo de animales con lesión del nervio facial mostraron signos de proliferación y activación a los 3, 7 y 21 días después de la lesión. Sin embargo, al cabo de cinco semanas, estas modificaciones se revirtieron, a pesar de que no hubo recuperación funcional de la parálisis facial. Conclusiones. La lesión irreversible del nervio facial produce proliferación y activación temprana y transitoria de las células de la microglía en el hipocampo. Estos cambios podrían estar asociados con las modificaciones electrofisiológicas y las alteraciones comportamentales dependientes del hipocampo descritas recientemente.


Introduction: Facial nerve injury induces changes in hippocampal long-term synaptic plasticity and affects both object recognition memory and spatial memory consolidation (i.e., hippocampus-dependent tasks). Although facial nerve injury-associated microglíal activation has been described regarding the primary motor cortex, it has not been ascertained whether something similar occurs in the hippocampus. Peripheral nerve injury- associated microglíal changes in hippocampal tissue could explain neuronal changes in the contralateral hippocampus. Objective: To characterize the effect of unilateral facial nerve injury on microglíal proliferation and activation in the contralateral hippocampus. Materials and methods: Immunohistochemical experiments detected microglíal cells in the hippocampal tissue of rats that had undergone facial nerve injury. The animals were sacrificed at specific times after injury to evaluate hippocampal microglíal cell proliferation (cell density) and activation (cell area); sham-operated animals were compared to lesioned animals sacrificed 1,3, 7, 21, or 35 days after injury. Results: Facial nerve-injured rats' hippocampal microglíal cells proliferated and adopted an activated phenotype 3- to 21-days post-lesion. Such modifications were transient since the microglíal cells returned to their resting state five weeks after injury, despite the injury's irreversible nature. Conclusions: Facial nerve injury causes the transient proliferation and activation of microglíal cells in the hippocampus. This finding might partly explain the morphological and electrophysiological changes described for CA1 pyramidal neurons and the impairment of spatial memory consolidation which has previously been observed in facial nerve-injured rats.


Subject(s)
Facial Nerve , Hippocampus , Rats , Immunohistochemistry
2.
Braz. J. Pharm. Sci. (Online) ; 58: e18807, 2022. graf
Article in English | LILACS | ID: biblio-1364413

ABSTRACT

Abstract This study aimed to investigate possible changes in the spatial memory of rats and the expression or activity of EGR-1, c-Fos, PKA, and PKC after propofol anesthesia. Thirty-six Sprague-Dawley rats aged 20 months and 36 Sprague-Dawley rats aged three months were each randomly divided into three groups: the control group, the Morris Water Maze (MWM) group, and the propofol group. In the propofol groups of both young and aged rats, the rats were anesthetized by propofol for two or four hours and then performed the MWM test two days or two weeks after anesthesia to assess cognitive function. EGR-1, c-Fos, PKA, and PKC expressions in the rat hippocampus were determined via immunohistochemistry. For the older rats, the escape latency in the P4h/2d group was significantly prolonged (P < 0.05), and the learning curve was right-shifted in the P4h/2w group (P < 0.05). The expression levels of EGR-1, c-Fos, PKA, and PKC in the MWM groups were significantly higher than those in the control groups (P < 0.05). In the P4h/2d group of aged rats, the expression levels of both PKA and PKC were decreased compared with those of the MWM groups. The decreased expression of both protein kinases may be responsible for the observed impairment after propofol anesthesia


Subject(s)
Animals , Male , Female , Rats , Propofol/pharmacology , Rats, Sprague-Dawley/classification , Morris Water Maze Test , Anesthesia/adverse effects , Cognition/classification , Cognitive Dysfunction/pathology , Spatial Memory , Hippocampus
3.
Frontiers of Medicine ; (4): 227-239, 2022.
Article in English | WPRIM | ID: wpr-929199

ABSTRACT

Chronic stress impairs radial neural stem cell (rNSC) differentiation and adult hippocampal neurogenesis (AHN), whereas promoting AHN can increase stress resilience against depression. Therefore, investigating the mechanism of neural differentiation and AHN is of great importance for developing antidepressant drugs. The nonpsychoactive phytocannabinoid cannabidiol (CBD) has been shown to be effective against depression. However, whether CBD can modulate rNSC differentiation and hippocampal neurogenesis is unknown. Here, by using the chronic restraint stress (CRS) mouse model, we showed that hippocampal rNSCs mostly differentiated into astrocytes under stress conditions. Moreover, transcriptome analysis revealed that the FoxO signaling pathway was involved in the regulation of this process. The administration of CBD rescued depressive-like symptoms in CRS mice and prevented rNSCs overactivation and differentiation into astrocyte, which was partly mediated by the modulation of the FoxO signaling pathway. These results revealed a previously unknown neural mechanism for neural differentiation and AHN in depression and provided mechanistic insights into the antidepressive effects of CBD.


Subject(s)
Animals , Cannabidiol/pharmacology , Cell Differentiation , Depression/prevention & control , Hippocampus/metabolism , Humans , Mice , Neural Stem Cells , Neurogenesis/physiology
4.
Neuroscience Bulletin ; (6): 474-488, 2022.
Article in English | WPRIM | ID: wpr-929086

ABSTRACT

Astrocytes are increasingly recognized to play an active role in learning and memory, but whether neural inputs can trigger event-specific astrocytic Ca2+ dynamics in real time to participate in working memory remains unclear due to the difficulties in directly monitoring astrocytic Ca2+ dynamics in animals performing tasks. Here, using fiber photometry, we showed that population astrocytic Ca2+ dynamics in the hippocampus were gated by sensory inputs (centered at the turning point of the T-maze) and modified by the reward delivery during the encoding and retrieval phases. Notably, there was a strong inter-locked and antagonistic relationship between the astrocytic and neuronal Ca2+ dynamics with a 3-s phase difference. Furthermore, there was a robust synchronization of astrocytic Ca2+ at the population level among the hippocampus, medial prefrontal cortex, and striatum. The inter-locked, bidirectional communication between astrocytes and neurons at the population level may contribute to the modulation of information processing in working memory.


Subject(s)
Animals , Astrocytes , Hippocampus/physiology , Humans , Memory, Short-Term/physiology , Mice , Neurons/physiology , Population Dynamics
5.
Neuroscience Bulletin ; (6): 209-222, 2022.
Article in English | WPRIM | ID: wpr-929079

ABSTRACT

Epilepsy is a common neurological disorder characterized by hyperexcitability in the brain. Its pathogenesis is classically associated with an imbalance of excitatory and inhibitory neurons. Calretinin (CR) is one of the three major types of calcium-binding proteins present in inhibitory GABAergic neurons. The functions of CR and its role in neural excitability are still unknown. Recent data suggest that CR neurons have diverse neurotransmitters, morphologies, distributions, and functions in different brain regions across various species. Notably, CR neurons in the hippocampus, amygdala, neocortex, and thalamus are extremely susceptible to excitotoxicity in the epileptic brain, but the causal relationship is unknown. In this review, we focus on the heterogeneous functions of CR neurons in different brain regions and their relationship with neural excitability and epilepsy. Importantly, we provide perspectives on future investigations of the role of CR neurons in epilepsy.


Subject(s)
Amygdala/metabolism , Calbindin 2/metabolism , Epilepsy , GABAergic Neurons , Hippocampus/metabolism , Humans
6.
Article in English | WPRIM | ID: wpr-928988

ABSTRACT

OBJECTIVES@#During pregnancy, pregnant women are prone to stress reactions due to external stimuli, affecting their own health and fetal development. At present, there is no good treatment for the stress reactions from pregnant women during pregnancy. This study aims to explore the effect of probiotics on abnormal behavior and hippocampal injury in pregnant stressed offspring.@*METHODS@#SD pregnant rats were divided into a control group, a stress group, and a probiotics group, with 6 rats in each group. The control group was untreated; the stress group was given restraint stress on the 15th-20th day of pregnancy; the probiotics group was given both bifidobacterium trisporus capsules and restraint stress on the 15th-20th day of pregnancy, and the offspring continued to be fed with probiotics until 60 days after birth (P60). The offspring rats completed behavioral tests such as the open field test, the elevated plus maze test, the new object recognition test, and the barnes maze test at 60-70 d postnatally. Nissl's staining was used to reflect the injury of hippocampal neurons; immunohistochemical staining was used to detect the expression of microglia marker ionized calcium binding adapter molecule 1 (IBA-1) which can reflect microglia activation; ELISA was used to detect the content of plasma TNF-α and IL-1β; Western blotting was used to detect the expression of Bax, Bcl-2, and caspase-3.@*RESULTS@#The retention time of offspring rats in the stress group in the central area of the open field was significantly less than that in the control group (P<0.01), and the retention time of offspring rats in the probiotic group in the central area of the open field was significantly more than that in the stress group (P<0.05). The offspring rats in the stress group stayed in the open arm for a shorter time than the control group (P<0.05) and entered the open arm less often than the control group (P<0.01); the offspring rats in the probiotic group stayed in the open arm for a longer time than the stress group and entered the open arm more often than the stress group (both P<0.05). The discrimination ratio for new to old objects in the offspring rats of the stress group was significantly lower than that of the control group (P<0.01), and the discrimination ratio for new to old objects in the offspring rats of the probiotic group was significantly higher than that of the stress group (P<0.05). The offspring rats in the stress group made significantly more mistakes than the control group (P<0.05), and the offspring rats in the probiotic group made significantly fewer mistakes than the stress group (P<0.05). Compared with the control group, the numbers of Nissl bodies in CA1, CA3, and DG area were significantly reduced in the offspring rats of the stress group (all P<0.001), the number of activated microglia in DG area of hippocampus was significantly increased (P<0.01), the contents of TNF-α and IL-1β in peripheral blood were significantly increased (P<0.05 or P<0.01), the protein expression level of Bcl-2 was significantly down-regulated, and the protein expression levels of Bax and caspase-3 were significantly up-regulated (all P<0.001). Compared with the stress group, the numbers of Nissl bodies in CA1, CA3, and DG area were significantly increased in the probiotic group offspring rats (P<0.001, P<0.01, P<0.05), the number of activated microglia in the DG area of hippocampus was significantly reduced (P<0.05), and the TNF-α and IL-1β levels in peripheral blood were significantly decreased (both P<0.05), the protein expression level of Bcl-2 was significantly up-regulated, and the protein expression levels of Bax and caspase-3 were significantly down-regulated (all P<0.001).@*CONCLUSIONS@#Probiotic intervention partially ameliorated anxiety and cognitive impairment in rats offspring of pregnancy stress, and the mechanism may be related to increasing the number of neurons, inhibiting the activation of hippocampal microglia, and reducing inflammation and apoptosis.


Subject(s)
Animals , Caspase 3/metabolism , Female , Hippocampus/physiopathology , Humans , Pregnancy , Probiotics/therapeutic use , Proto-Oncogene Proteins c-bcl-2/metabolism , Rats , Stress, Psychological/therapy , Tumor Necrosis Factor-alpha/metabolism , bcl-2-Associated X Protein/metabolism
7.
Article in English | WPRIM | ID: wpr-928956

ABSTRACT

OBJECTIVE@#To investigate the pharmacodynamic material basis, mechanism of actions and targeted diseases of Salicornia europaea L. (SE) based on the network pharmacology method, and to verify the antidepressant-like effect of the SE extract by pharmacological experiments.@*METHODS@#Retrieval tools including Chinese medicine (CM), PubMed, PharmMapper, MAS 3.0 and Cytoscape were used to search the components of SE, predict its targets and related therapeutic diseases, and construct the "Component-Target-Pathway" network of SE for central nervous system (CNS) diseases. Further, protein-protein interaction (PPI) network, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) function annotation of depression-related targets were analyzed to predict the antidepressant mechanism of SE. Chronic unpredictable mild stress (CUMS) model was used to construct a mouse model with depression-like symptoms. And the animals were randomly divided into 6 groups (n=10) including the normal group (nonstressed mice administered with distilled water), the CUMS group (CUMS mice administered with distilled water), the venlafaxine group (CUMS mice administered with venlafaxine 9.38 mg/kg), SE high-, medium-, and low-dose groups (CUMS mice administered with SE 1.8, 1.35 and 0.9 g/kg, respectively). Then some relevant indicators were determined for experimental verification by the forced swim test (FST), the tail suspension test (TST) and open-field test (OFT). Dopamine (DA) concentration in hippocampus and cerebral cortex, IL-2 and corticosterone (CORT) levels in blood, and nuclear factor E2 related factor 2 (Nrf2), kelch-like epichlorohydrin related protein 1 (Keap1), NAD(P) H dehydrogenase [quinone] 1 (NQO1) and heme oxygenase-1 (HO-1) levels in mice were measured by enzyme linked immunosorbent assay (ELISA) and Western blot respectively to explore the possible mechanisms.@*RESULTS@#The "target-disease" network diagram predicted by network pharmacology, showed that the potential target of SE involves a variety of CNS diseases, among which depression accounts for the majority. The experimental results showed that SE (1.8, 1.35 g/kg) significantly decreased the immobility period, compared with the CUMS group in FST and TST in mice after 3-week treatment, while SE exhibited no significant effect on exploratory behavior in OFT in mice. Compared with CUMS group, the SE group (0.9 g/kg) showed significant differences (P<0.05) in DA levels in the hippocampus and cerebral cortex. In addition, compared with CUMS control group, SE (1.8 g/kg) group showed a significant effect on decreasing the activities of CORT (P<0.05), and serum IL-2 level with no statistical significance. Finally, Western blot results showed that compared with the model group, Nrf2, Keap1, NQO1 and HO-1 protein expressions in SE group (1.8 g/kg) were up-regulated (all P<0.01).@*CONCLUSION@#The SE extract may have an antidepressant effect, which appeared to regulate Nrf2-ARE pathway and increased levels of DA and CORT in the hippocampus and cortex.


Subject(s)
Animals , Antidepressive Agents/therapeutic use , Behavior, Animal , Chenopodiaceae/metabolism , Depression/drug therapy , Disease Models, Animal , Hippocampus , Kelch-Like ECH-Associated Protein 1/metabolism , Mice , NF-E2-Related Factor 2/metabolism , Network Pharmacology , Plant Extracts/therapeutic use , Stress, Psychological/drug therapy
8.
Article in Chinese | WPRIM | ID: wpr-941024

ABSTRACT

OBJECTIVE@#To explore the mechanism by which berberine inhibits ferroptosis of mouse hippocampal neuronal cells (HT22).@*METHODS@#Cultured HT22 cells were pretreated with 30 or 60 μmol/L berberine for 2 h before exposure to 0.5 μmol/L erastin for 8 h, and the cell proliferation, intracellular ferric iron level, changes in intracellular reactive oxygen species (ROS) and cell apoptosis were detected using CCK-8, Fe2+ fluorescent probe, fluorescent dye (DAPI) and fluorescent probe (H2DCFH-DA). RT-qPCR and Western blotting were used to detect the mRNA and protein expressions of Nrf2, HO-1 and GPX4 in the cells. We further tested the effects of treatments with 2 μmol/L ML385 (a Nrf2 inhibitor), 60 μmol/L berberine and erastin in the cells to explore the protective mechanism of berberine against erastin-induced ferroptosis in the neuronal cells.@*RESULTS@#Treatment with 0.5 μmol/L erastin significantly lowered the viability of HT22 cells (P < 0.05) and increased the production of ROS, cell apoptosis rate and ferric iron level (P < 0.05). Pretreatment with 30 and 60 μmol/L berberine both significantly increased the vitality of erastin-exposed cells (P < 0.05) and lowered the levels of intracellular ROS and ferric iron content (P < 0.05). RT-qPCR and Western blotting showed that berberine obviously promoted the expressions of Nrf2, HO-1 and GPX4 in the cells (P < 0.05), and treatment with ML385 significantly inhibited the Nrf2-HO-1/GPX4 pathway, increased intracellular ROS and ferric iron contents and mitigated the protective effect of berberine against erastin-induced ferroptosis (P < 0.05).@*CONCLUSION@#Berberine can inhibit erastin-induced ferroptosis in HT22 cells possibly by activating the Nrf2-HO-1/ GPX4 pathway.


Subject(s)
Animals , Berberine/pharmacology , Ferroptosis , Fluorescent Dyes , Hippocampus/metabolism , Iron/metabolism , Mice , NF-E2-Related Factor 2/metabolism , Piperazines , Reactive Oxygen Species/metabolism
9.
Article in English | WPRIM | ID: wpr-939588

ABSTRACT

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.


Subject(s)
Animals , Cell Proliferation , Ecdysterone/pharmacology , Hippocampus/metabolism , Male , Memory Disorders , Microwaves , Neural Stem Cells/physiology , Rats , Rats, Sprague-Dawley , beta Catenin/metabolism
10.
Article in Chinese | WPRIM | ID: wpr-936136

ABSTRACT

OBJECTIVE@#To investigate the effects of CACNA1H gene knockout (KO) on autistic-like behaviors and the morphology of hippocampal neurons in mice.@*METHODS@#In the study, 25 CACNA1H KO mice of 3-4 weeks old and C57BL/6 background were recruited as the experimental group, and 26 wild type (WT) mice of the same age and background were recruited as the control group. Three-chamber test and open field test were used to observe the social interaction, anxiety, and repetitive behaviors in mice. After that, their brain weight and size were measured, and the number of hippocampal neurons were observed by Nissl staining. Furthermore, the CACNA1H heterozygote mice were interbred with Thy1-GFP-O mice to generate CACNA1H-/--Thy1+(KO-GFP) and CACNA1H+/+-Thy1+ (WT-GFP) mice. The density and maturity of dendritic spines of hippocampal neurons were observed.@*RESULTS@#In the sociability test session of the three-chamber test, the KO mice spent more time in the chamber of the stranger mice than in the object one (F1, 14=95.086, P < 0.05; Post-Hoc: P < 0.05), without any significant difference for the explored preference index between the two groups (t=1.044, P>0.05). However, in the social novelty recognition test session, no difference was observed between the time of the KO mice spend in the chamber of new stranger mice and the stranger one (F1, 14=18.062, P < 0.05; Post-Hoc: P>0.05), and the explored preference index of the KO mice was less than that of the control group (t=2.390, P < 0.05). In the open field test, the KO mice spent less time in the center of the open field apparatus than the control group (t=2.503, P < 0.05), but the self-grooming time was significantly increased compared with the control group (t=-2.299, P < 0.05). Morphological results showed that the brain weight/body weight ratio (t=0.356, P>0.05) and brain size (t=-0.660, P>0.05) of the KO mice were not significantly different from those of the control group, but the number of neurons were significantly reduced in hippocampal dentate gyrus compared with the control group (t=2.323, P < 0.05). Moreover, the density of dendritic spine of dentate gyrus neurons in the KO-GFP mice was significantly increased compared with the control group (t=-2.374, P < 0.05), without any significant difference in spine maturity (t=-1.935, P>0.05).@*CONCLUSION@#CACNA1H KO mice represent autistic-like behavior, which may be related to the decrease in the number of neurons and the increase in the density of dendritic spine in the dentate gyrus.


Subject(s)
Animals , Autistic Disorder/genetics , Calcium Channels, T-Type/genetics , Gene Knockout Techniques , Hippocampus , Mice , Mice, Inbred C57BL , Mice, Knockout , Neurons
11.
Article in Chinese | WPRIM | ID: wpr-936110

ABSTRACT

OBJECTIVE@#To investigate the influence of chronic masseter hyperalgesia induced by 17β-estradiol (E2) and experimental occlusal interference (EOI) on underlying mechanism in hippocampus of ovariectomized (OVX) rats.@*METHODS@#In the study, 32 OVX rats were randomly divided into 4 groups (8 rats/group): The control group was OVX group, and 0 μg/d E2 (vehicle) injection was started 7 d after OVX without EOI; in the experimental group (1) OVX + E2 group, 80 μg/d E2 injection was started 7 d after OVX without EOI; in the experimental group (2) OVX + EOI group, vehicle injection was started 7 d after OVX and EOI was applied 17 d after OVX; in the experimental group (3) OVX + E2 + EOI group, 80 μg/d E2 injection was started 7 d after OVX and EOI was applied 17 d after OVX. Bilateral masseter muscle mechanical withdrawal thresholds were measured before OVX, 7 days after OVX (before E2 injection), 17 days after OVX (10 days after E2 injection and before EOI) and 24 days after OVX (7 days after EOI). Immunofluorescence staining was used to reveal phospho-extracellular signal regulated kinase 1/2 (p-ERK1/2)-positive neurons in CA3 of hippocampus. The protein expression of p-ERK1/2 in hippocampus was detected using Western Blot.@*RESULTS@#Compared with the control group [left side: (135.3±8.5) g, right side: (135.4±10.8) g], bilateral masseter muscle mechanical withdrawal thresholds of OVX+E2 group [left side: (113.3±5.6) g, right side: (112.5 ± 5.6) g] and OVX+EOI group [left side: (93.3±5.4) g, right side: 90.8±5.5) g] were decreased (P < 0.01). Bilateral masseter muscle mechanical withdrawal thresholds were significantly lower in OVX+E2+EOI group [left side: (81.2±6.2) g, right side: 79.8±7.7) g] than in the control, OVX+E2 and OVX+EOI groups (P < 0.05). The proportion of p-ERK1/2 positive neurons in the CA3 region of the hippocampus was increased in the control, OVX+E2, OVX+EOI and OVX+E2+EOI groups in turn, and the difference between the groups was statistically significant (P < 0.05). p-ERK1/2 protein expression was increased in the control, OVX+E2 and OVX+EOI groups in turn, but the difference was not statistically significant (P>0.05). p-ERK1/2 expression was significantly higher in OVX+E2+EOI group than in the other three groups (P < 0.05).@*CONCLUSION@#High concentration of E2 could exacerbated EOI-induced chronic masseter hyperalgesia in ovariectomized rats, and its central mechanism may be related to the upregulation of the phosphorylation of ERK1/2 in hippocampus.


Subject(s)
Animals , Estradiol , Female , Hippocampus , Humans , Hyperalgesia/chemically induced , Masseter Muscle , Ovariectomy , Rats , Rats, Sprague-Dawley
12.
Chinese Journal of Stomatology ; (12): 375-383, 2022.
Article in Chinese | WPRIM | ID: wpr-935870

ABSTRACT

Objectives: To study the effects of Porphyromonas gingivalis (Pg) injected through tail vein on the molecular expression levels of biomarkers of neural stem cells (NSC) and neurons in the hippocampus of wild-type adult rats, and the effects on hippocampal neurogenesis. Methods: Eighteen male Sprague-Dawley (SD) rats were randomly divided into 3 groups based on the table of random numbers (n=6 in each group). In low-intensity group and high-intensity group, rats were injected intravenously through tail vein with 200 μl Pg ATCC33277 [1.0×103 and 1.0×108 colony forming unit (CFU), respectively] 3 times per week for 8 weeks. In the sham group, 200 μl of phosphate buffer saline (PBS) was given instead. Behavioral tests: the navigation and the exploration tests using Morris water maze (MWM) were applied to evaluate learning and memory ability of rats. Immunohistochemistry was performed to detect cells positively expressing nestin, doublecortin (DCX) and neuronal nuclei (NeuN) in the subgranular zone (SGZ) of rats in each group. Western blotting was used to evaluate the expression levels of nestin, DCX and NeuN in rat hippocampus. Results: Learning and memory abilities: on day 5 of navigation test, the lagency time was 22.83 (16.00, 38.34) s in the high-intensity group, significantly longer than the sham group [5.59 (5.41, 6.17) s] (t=-11.17, P<0.001). There were no significant differences between the low-intensity group [9.85 (8.75, 21.01) s] and the sham group (t=-6.83, P=0.080). Results in the exploration test showed that, in the high-intensity group, the number of fime crossing over the previous platform area within 60 s was 1.50 (1.00, 2.00), significantly less than the sham group [4.00 (2.75, 4.00)] (t=9.75, P=0.003); no significant differences between the low-intensity group [2.50 (2.00, 3.00)] and the sham one (t=4.50, P=0.382). Immunohistochemistry showed that the nestin+ cell density in the low-intensity group [(35.36±4.32) cell/mm2] and high-intensity group [(26.51±5.89) cell/mm2] were significantly lower than the sham group [(59.58±14.15) cell/mm2] (t=24.21, P=0.018; t=33.07, P=0.005); as for the mean absorbance of DCX+ cells, the low-intensity group (0.007±0.002) and the high-intensity group (0.006±0.002) were significantly lower than the sham group (0.011±0.001) (t=0.004, P=0.018; t=0.006, P=0.005); compared with the sham group [(1.13±0.14)×103 cell/mm2], the density of NeuN+ neurons in the high-intensity group [(0.75±0.08)×103 cell/mm2] was significantly reduced (t=0.38, P=0.017), and was not significantly changed in the low-intensity group [(0.88±0.19)×103 cell/mm2] (t=0.25, P=0.075). Western blotting results showed that, compared with the sham group, the expression levels of nestin, DCX, and NeuN were significantly reduced in the high-intensity group (t=0.74, P<0.001; t=0.18, P=0.014; t=0.35, P=0.008), but were not statistically changed in the low-intensity group (t=0.18, P=0.108; t=0.08, P=0.172; t=0.19, P=0.077). Conclusions: Pg injected through tail vein may reduce learning and memory abilities of wild-type rats, and may reduce the number of nestin, DCX, and NeuN-positive cells, and the protein expression levels of the above molecules in the hippocampus.


Subject(s)
Animals , Biomarkers/metabolism , Hippocampus/metabolism , Male , Nestin/metabolism , Neural Stem Cells/metabolism , Neurons/metabolism , Porphyromonas gingivalis/metabolism , Rats , Rats, Sprague-Dawley , Tail/metabolism
13.
Article in Chinese | WPRIM | ID: wpr-935769

ABSTRACT

Objective: To investigate the effect and underlying mechanism of paeoniflorin on hippocampal neuron apoptosis induced by lead acetate. Methods: In September 2020, primary hippocampal neuronal cells were isolated and cultured from fetal rats, and identified using cellular immunofluorescent. MTT assay was used to measure the cell viability to determine the concentration and time of lead acetate-induced hippocampal neuron apoptosis. MTT was also used to evaluate the effect of paeoniflorin concentration on the apoptosis of hippocampal neurons induced by lead acetate. According to the results, different concentrations of paeoniflorin were selected to intervene hippocampal neuron cells, after 24 h, lead acetate was added to the cells, meanwhile, blank and model groups were set up, the content of reactive oxygen species (ROS) , superoxide dismutase (SOD) , lactate dehydrogenase (LDH) , malondialdehyde (MDA) and Caspase-3 were measured. Extracellular signal regulated kinase (ERK) , phosphorylated ERK (p-ERK) , p38 mitogen -activated protein kinases (p38MAPK) , phosphorylated p38MAPK (p-p38MAPK) , c-Jun N-terminal kinase (JNK) and phosphorylated JNK (p-JNK) protein expression in hippocampal neuronal cells were determined by Western blotting. Results: The isolated and cultured hippocampal neurons were identified by immunofluorescence chemical staining and then treated with lead acetate, MTT results showed that lead acetate had the best toxicity effect when treated for 24 h at a concentration of 25 μmol/L. Paeoniflorin showed no cytotoxic effect on hippocampal neuronal cells when the concentrations below 80 μmol/L. Compared with the model group, the activity of hippocampal neuronal cells was significantly increased after treating with 20, 40 or 80 μmol/L paeoniflorin (P<0.05) . Compared with the blank group, the ROS activity, LDH release level, MDA content and caspase-3 content were significantly increased (P<0.01) , and the SOD activity was significantly decreased (P< 0.01) in the hippocampal neuronal cells of the model group. Compared with the model group, the ROS activity, LDH release level, MDA content and caspase-3 content were obviously decreased (P<0.05) , SOD activity was significantly increased (P <0.01) after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin. Relative to the model group, the ratio of p-ERK/ERK were significantly up-regulated (P<0.01) , while the ratios of p-p38MAPK/p38MAPK and p-JNK/JNK were significantly down-regulated after hippocampal neuronal cells were treated with 40 or 80 μmol/L paeoniflorin (P<0.05) . Conclusion: Paeoniflorin may down-regulate the expression of p-p38MAPK and p-JNK protein, up-regulate the expression of p-ERK protein, and inhibit the apoptosis of hippocampal neurons induced by lead acetate through the MAPK signaling pathway.


Subject(s)
Acetates/pharmacology , Animals , Apoptosis , Caspase 3/metabolism , Extracellular Signal-Regulated MAP Kinases/metabolism , Glucosides , Hippocampus/metabolism , JNK Mitogen-Activated Protein Kinases/pharmacology , Lead , Monoterpenes , Neurons/metabolism , Rats , Reactive Oxygen Species/metabolism , Superoxide Dismutase/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism
14.
Article in English | WPRIM | ID: wpr-922579

ABSTRACT

OBJECTIVE@#To investigate whether electroacupuncture (EA) alleviates cognitive impairment by suppressing the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signaling pathway, which triggers immune-inflammatory responses in the hippocampus of rats with vascular dementia (VaD).@*METHODS@#The experiments were conducted in 3 parts and in total the Sprague-Dawley rats were randomly divided into 8 groups by a random number table, including sham, four-vessel occlusion (4-VO), 4-VO+EA, 4-VO+non-EA, sham+EA, 4-VO+lipopolysaccharide (LPS), 4-VO+LPS+EA, and 4-VO+TAK-242 groups. The VaD model was established by the 4-VO method. Seven days later, rats were treated with EA at 5 acupoints of Baihui (DV 20), Danzhong (RN 17), Geshu (BL 17), Qihai (RN 6) and Sanyinjiao (SP 6), once per day for 3 consecutive weeks. Lymphocyte subsets, lymphocyte transformation rates, and inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor α(TNF-α) were measured to assess immune function and inflammation in VaD rats. Transmission electron microscopy was used to observe the ultrastructure of nerve cells in the hippocampus. The levels of TLR4, MyD88, IL-6, and TNF-α were detected after EA treatment. TLR4/MyD88 signaling and cognitive function were also assessed after intracerebroventricular injection of TLR4 antagonist TAK-242 or TLR4 agonist LPS with or without EA.@*RESULTS@#Compared with the 4-VO group, EA notably improved immune function of rats in the 4-VO+EA group, inhibited the protein and mRNA expressions of TLR4 and MyD88 in the hippocampus of rats, reduced the expressions of serum IL-6 and TNF-α (all P0.05).@*CONCLUSIONS@#EA attenuated cognitive impairment associated with immune inflammation by inhibition of the TLR4/MyD88 signaling pathway. Thus, EA may be a promising alternative therapy for the treatment of VaD.


Subject(s)
Animals , Dementia, Vascular/therapy , Electroacupuncture , Hippocampus/metabolism , Immunity , Myeloid Differentiation Factor 88 , Rats , Rats, Sprague-Dawley , Signal Transduction , Toll-Like Receptor 4/metabolism
15.
Article in Chinese | WPRIM | ID: wpr-928217

ABSTRACT

Physiological studies reveal that rats rely on multiple spatial cells for spatial navigation and memory. In this paper, we investigated the firing mechanism of spatial cells within the entorhinal-hippocampal structure of the rat brain and proposed a spatial localization model for mobile robot. Its characteristics were as follows: on the basis of the information transmission model from grid cells to place cells, the neural network model of place cells interaction was introduced to obtain the place cell plate with a single-peaked excitatory activity package. Then the solution to the robot's position was achieved by establishing a transformation relationship between the position of the excitatory activity package on the place cell plate and the robot's position in the physical environment. In this paper, simulation experiments and physical experiments were designed to verify the model. The experimental results showed that compared with RatSLAM and the model of grid cells to place cells, the positioning performance of the model in this paper was more accurate, and the cumulative error in the long-time path integration process of the robot was also smaller. The research results of this paper lay a foundation for the robot navigation method that mimics the cognitive mechanism of rat brain.


Subject(s)
Animals , Cognition , Hippocampus , Models, Neurological , Place Cells , Rats , Robotics
16.
Article in Chinese | WPRIM | ID: wpr-928189

ABSTRACT

With the ultra high performance liquid chromatography-quadruple-electrostatic field orbitrap high resolution mass spectrometry(UHPLC-Q Exactive Orbitrap-MS)-based metabonomics technology, this study aims to analyze the effect of Chaiqin Ningshen Granules(CNG) on endogenous metabolites in insomnia rats of liver depression syndrome and explore the sleep-improving mechanism of this prescription. Parachlorophenylalanine(PCPA, ip) and chronic stimulation were combined to induce insomnia of liver depression pattern in rats, and the effect of CNG on the macroscopic signs, hemorheology, and neurotransmitters in the hippocampus of insomnia rats of liver depression syndrome was observed. After the administration, rat hippocampus was collected for liquid chromatography-mass spectrometry(LC-MS) analysis of the metabolomics. Principal component analysis(PCA), partial least squares discriminant analysis(PLS-DA), and orthogonal partial least squares discriminant analysis(OPLS-DA) were employed for analyzing the metabolites in rat hippocampus and screening potential biomarkers. MetPA was used to yield the related metabolic pathways and metabolic networks. The results show that the drugs can significantly improve the mental state, liver depression, and blood stasis of rats, significantly increase the content of 5-hydroxytryptamine(5-HT) and gamma aminobutyric acid(GABA) in hippocampus(except low-dose CNG), and significantly reduce the content of glucose(Glu)(except low-dose CNG). Among them, estazolam and high-dose CNG had better effect than others. Metabolomics analysis yielded 27 potential biomarkers related to insomnia. MetPA analysis showed 4 metabolic pathways of estazolam in intervening insomnia and 3 metabolic pathways of high-dose CNG in intervening insomnia, involving purine metabolism, glycerophospholipid metabolism, histidine metabolism, and caffeine metabolism. CNG can alleviate insomnia by regulating endogenous differential metabolites and further related metabolic pathways. The result lays a basis for further elucidating the mechanism of CNG in improving sleep.


Subject(s)
Animals , Biomarkers , Chromatography, High Pressure Liquid , Drugs, Chinese Herbal/pharmacology , Estazolam , Hippocampus/metabolism , Metabolomics/methods , Rats , Sleep , Sleep Initiation and Maintenance Disorders/drug therapy
17.
Article in Chinese | WPRIM | ID: wpr-928147

ABSTRACT

The present study investigated the mechanism of the Tibetan patent medicine Ershiwuwei Shanhu Pills(ESP) in alleviating Alzheimer's disease in mice via Akt/mTOR/GSK-3β signaling pathway. BALB/c mice were randomly assigned into a blank control group, a model group, low(200 mg·kg~(-1)), medium(400 mg·kg~(-1)) and high(800 mg·kg~(-1)) dose groups of ESP, and donepezil hydrochloride group. Except the blank control group, the other groups were given 20 mg·kg~(-1) aluminum chloride by gavage and 120 mg·kg~(-1) D-galactose by intraperitoneal injection for 56 days to establish Alzheimer's disease model. Morris water maze was used to detect the learning and memory ability of mice. The level of p-tau protein in mouse hippocampus and the levels of superoxide dismutase(SOD), malondialdehyde(MDA), catalase(CAT), and total antioxidant capacity(T-AOC) in hippocampus and serum were detected. Hematoxylin-eosin staining and Nissl staining were performed for the pathological observation of whole brain in mice. TdT-mediated dUTP nick-end labeling(TUNEL) staining was employed for the observation of apoptosis in mouse cortex. Western blot was adopted to detect the protein levels of p-mTOR, p-Akt, and GSK-3β in the hippocampus. Compared with the model group, the ESP groups showcased alleviated pathological damage of the whole brain, decreased TUNEL positive cells, reduced level of p-tau protein in hippocampus, and risen SOD, CAT, and T-AOC levels and declined MDA level in hippocampus and serum. Furthermore, the ESP groups had up-regulated protein levels of p-mTOR and p-Akt while down-regulated protein level of GSK-3β in hippocampus. Therefore, ESP can alleviate the learning and memory decline and oxidative damage in mice with Alzheimer's disease induced by D-galactose combined with aluminum chloride, which may be related to Akt/mTOR/GSK-3β signaling pathway.


Subject(s)
Aluminum Chloride/adverse effects , Alzheimer Disease/drug therapy , Animals , Galactose/metabolism , Glycogen Synthase Kinase 3 beta/metabolism , Hippocampus/metabolism , Mice , Mice, Inbred BALB C , Plant Extracts , Proto-Oncogene Proteins c-akt/metabolism , Signal Transduction , Superoxide Dismutase/metabolism , TOR Serine-Threonine Kinases/metabolism , tau Proteins
18.
Article in Chinese | WPRIM | ID: wpr-927953

ABSTRACT

The effects of Jingui Shenqi Pills(Jingui) and Liuwei Dihuang Pills(Liuwei) which respectively tonify kidney Yang and kidney Yin on brain function have attracted great attention, while the differences of protein expression regulated by Jingui and Liuwei remain to be studied. This study explored the difference of protein expression profiles in the hippocampi of mice orally administrated with the two drugs for 7 days. The protein expression was quantified using LC-MS/MS. The results showed that among the 5 860 proteins tested, 151, 282 and 75 proteins responded to Jingui alone, Liuwei alone, and both drugs, respectively. The ratio of up-regulated proteins to down-regulated proteins was 1.627 in Jingui group while only 0.56 in Liuwei group. The proteins up-regulated by Jingui were mainly involved in membrane transport, synaptic vesicle cycle, serotonergic synapse, dopaminergic synapse and so on, suggesting that Jingui may play a role in promoting the transport of neurotransmitter in the nervous system. The proteins down-regulated by Liuwei were mainly involved in membrane transport, synapse, ion transport(potassium and sodium transport), neurotransmitter transport, innate and acquired immune responses, complement activation, inflammatory response, etc. In particular, Liuwei showed obvious down-regulation effect on the members of solute carrier(SLC) superfamily, which suggested that Liuwei had potential inhibitory effect on membrane excitation and transport. Finally, consistent results were obtained in the normal mouse and the mouse model with corticosterone-induced depressive-like behavior. This study provides an experimental basis for understanding the effect of Jingui and Liuwei on brain function from protein network.


Subject(s)
Animals , Chromatography, Liquid , Drugs, Chinese Herbal/pharmacology , Hippocampus/metabolism , Mice , Proteome/metabolism , Proteomics , Tandem Mass Spectrometry
19.
Article in Chinese | WPRIM | ID: wpr-927921

ABSTRACT

The present study explored the effect and mechanism of repeatedly steamed and sundried Rehmanniae Radix Praeparata(RRP) in delaying brain aging in ovariectomized mice. After ovariectomy, the mice were randomly divided into a model group, an estradiol valerate group(0.3 mg·kg~(-1)), and low-(1.0 g·kg~(-1)), medium-(2.0 g·kg~(-1)), and high-dose(4.0 g·kg~(-1)) RRP groups, and a sham operation group was also set up, with 15 mice in each group. One week after the operation, intragastric administration was carried out for 15 consecutive weeks. The step-down test and Morris water maze test were used to detect the behavioral changes of mice. HE staining and Nissl staining were used to observe the morphological changes of mouse brain tissues. Immunohistochemistry was used to detect the expression of Aβ and ER_β in mouse brain tissues. The serum estrogen levels and cholinesterase and cholinesterase transferase levels in brain tissues of mice were detected by assay kits. The extracted hippocampal protein was detected by the Nano-ESI-LC-MS system, identified by the Protein Discovery, and analyzed quantitatively and qualitatively by the SIEVE. The PANTHER Classification System was used for GO analysis and KEGG pathway enrichment analysis of the differential proteins. Compared with the sham operation group, the model group showed decreased learning and memory ability, shortened step-down latency(P<0.05), prolonged escape latency(P<0.05), reduced platform crossings and residence time in the target quadrant, scattered nerve cells in the hippocampus with enlarged intercellular space, increased expression of Aβ-positive cells(P<0.05), declining expression of ER_β-positive cells and estrogen level(P<0.05), and weakened cholinergic function(P<0.05). Compared with the model group, the RRP groups showed improved learning and memory ability, prolonged step-down latency(P<0.05), increased estrogen level(P<0.05), neatly arranged nerve cells in the hippocampus with complete morphology, declining Aβ-positive cells, and elevated expression of ER_β-positive cells. A total of 146 differential proteins were screened out by proteomics, and KEGG pathway enrichment yielded 75 signaling pathways. The number of proteins involved in the dopaminergic synapse signaling pathway was the largest, with 13 proteins involved. In summary, RRP can delay brain aging presumedly by increasing the level of estrogen, mediating the dopaminergic synapse signaling pathway, and improving cholinergic function.


Subject(s)
Aging , Animals , Female , Hippocampus/metabolism , Learning , Mice , Plant Extracts , Proteomics , Rehmannia
20.
Article in Chinese | WPRIM | ID: wpr-927891

ABSTRACT

Objective: To uncover the time-dependent expression pattern of ptk2b gene and ptk2b-encoded protein, protein tyrosine kinase 2 beta(PTK2B), in the brain tissues of transgenic animal models of Alzheimer's disease (AD) and its relationship with the levels of Aβ1-42, phosphorylation of Tau (p-Tau) and low density lipoprotein receptor-related protein-1(LRP-1) in blood and brain tissues. Methods: In this study, 5-, 10- and 15-month-old APPswe/PS1dE9 double-transgenic mice harboring the genotype of AD confirmed by the gene test were divided into the 5-, 10- and 15-month-old experiment groups, and simultaneously, age-matched C57BL/6J mice were placed into the corresponding control groups, with 8 mice in each group. All mice were subjected to the Morris Water Maze for test of cognitive and behavioral ability. Expression profiles of PTK2B, Aβ1-42, p-Tau/Tau and LRP-1 in the hippocampus or blood of mice were quantified by using the immunohistochemistry staining, Western blot or enzyme-linked immunosorbent assay (ELISA), while the mRNA expression of ptk2b in the hippocampus was quantified by using the real-time quantitative polymerase chain reaction (qRT-PCR). Results: Results of experiment groups demonstrated that as mice aged, the expression levels of PTK2B, ptk2b mRNA, Aβ1-42 and p-Tau/Tau in the hippocampus were increased, and the expression of LRP-1 was decreased gradually. While in the blood, the level of Aβ1-42 was decreased, and the cognitive and behavioral ability was decreased in an age-dependent manner (all P< 0.05). However, comparisons among the control groups, only the age-dependent downregulation of LRP-1 were observed in hippocampus(P<0.05), but other indicators had no significant differences (P>0.05). Conclusion: In the hippocampus of APP/PS1 double-transgenic mice, the expressions of PTK2B, Aβ1-42 and p-Tau/Tau are upregulated, LRP-1 is downregulated, while cognitive and behavioral ability is decreased, and such changes are presented in a time-dependent manner.


Subject(s)
Alzheimer Disease/metabolism , Amyloid beta-Peptides , Amyloid beta-Protein Precursor/genetics , Animals , Focal Adhesion Kinase 2/metabolism , Hippocampus/metabolism , Low Density Lipoprotein Receptor-Related Protein-1 , Maze Learning , Mice , Mice, Inbred C57BL , Mice, Transgenic , RNA, Messenger
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