OBJECTIVE: To observe the effects of "olfactory three needles" on cognition, learning and memory abilities, as well as hippocampal microglia (MG) phagocytic activity in vascular dementia (VD) rats, and explore the mechanisms of acupuncture in regulating MG activation and improving remyelination, so as to ameliorate VD. METHODS: Among 38 SD rats meeting experimental requirements, 9 rats were randomly assigned to a sham-operation group, and the remaining rats underwent permanent bilateral common carotid artery ligation to establish VD model. Eighteen successfully modeled rats were randomly divided into a model group and an electroacupuncture (EA) group, with 9 rats in each one. In the EA group, EA was performed at "olfactory three needles" ("Yintang" [GV24⁺] and bilateral "Yingxiang" [LI20]), at disperse-dense wave, the frequency of 2 Hz/15 Hz and the current intensity of 1 mA, for 15 min per intervention, once daily. One course was composed of 7 days, and 2 courses were required, with the interval of 2 days. The novel object recognition test was employed to assess the cognition of rats, and the Morris water maze was adopted to observe learning and memory abilities. Luxol fast blue (LFB) staining was performed to evaluate myelin sheath loss in the hippocampus, the Western blot was used to detect the protein expression of triggering receptor expressed on myeloid cells-2 (TREM2) and proteolipid protein (PLP) in the hippocampus; and the immunofluorescence staining was used to detect the positive expression of PLP, sex determining region Y-box 10 (SOX10), ionized calcium binding adaptor molecule 1 (Iba1)⁺ TREM2⁺ and Iba1⁺ lysosome-associated membrane protein 1 (LAMP1)⁺ in the hippocampus. RESULTS: Compared with the sham-operation group, the rats in the model group exhibited the prolonged escape latency on day 3 and 4 (P<0.05, P<0.01), the increase of the total distance traveling (P<0.01) and the decrease of the recognition index (RI) and platform crossing frequency (P<0.01). Compared with the model group, the rats in the EA group showed the shortened escape latency on day 3 and 4 (P<0.05), the decrease of total distance traveling (P<0.01) and the increase of RI and platform crossing frequency (P<0.05, P<0.01). When compared with the sham-operation group, the rats of the model group presented uneven staining, sparse arrangement of myelin sheath fibers, unclear contours, and prominent vacuole-like changes in the hippocampal CA1 region. When compared with the model group, the EA group showed more dense staining, the increase of myelin sheath fibers with more orderly alignment, and fewer vacuolar changes in the hippocampal CA1 region. Compared with the sham-operation group, the model group exhibited the increase of TREM2 protein expression and the decrease of PLP protein expression in the hippocampus (P<0.01), whereas the EA group showed the up-regulation of TREM2 and PLP protein expression when compared with the model group (P<0.01, P<0.05). The positive expression of the hippocampal PLP, SOX10, and Iba1⁺LAMP1⁺ in the model group was reduced in comparison with the sham-operation group (P<0.05, P<0.01), and the positive expression of Iba1⁺ TREM2⁺ was elevated (P<0.05). In the EA group, the positive expression of PLP, SOX10, Iba1⁺TREM2⁺, and Iba1⁺ LAMP1⁺ was higher compared with that in the model group (P<0.05, P<0.01). CONCLUSION "Olfactory three needles" can improve the learning and memory, and cognitive functions of VD rats, and its mechanism may be associated with the up-regulation of TREM2 and LAMP1 to adjust MG phagocytic activity and intracellular degradation, and promote remyelination.
Animals ; Dementia, Vascular/metabolism* ; Rats ; Rats, Sprague-Dawley ; Microglia/metabolism* ; Male ; Acupuncture Therapy/instrumentation* ; Acupuncture Points ; Humans ; Remyelination ; Memory ; Hippocampus/cytology* ; Cognition ; Electroacupuncture ; Needles

OBJECTIVE: To observe the effects of Tongdu Tiaoshen acupuncture (acupuncture for unblocking the obstruction in the governor vessel and regulating the spirit) on the depression-like behavior and the hippocampal neuronal ferroptosis mediated by solute carrier family 7 member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) pathway in depression rats, and explore the mechanism of this therapy for depression. METHODS: Of 30 male SD rats of SPF grade, 24 rats were selected. According to the random number table, they were divided into a normal group (n=8) and a modeling group (n=16). The rats in the modeling group were subjected to chronic unpredictable mild stress (CUMS) for 28 consecutive days to establish depression model. After modeling, 16 successfully-modeled rats were randomly divided into a model group and an acupuncture group, 8 rats in each one. In the acupuncture group, Tongdu Tiaoshen acupuncture was applied to "Dazhui"(GV14), "Shuigou" (GV26), "Baihui" (GV20) and "Shenting" (GV24). This intervention measure was deliveredonce a day, continuously for 6 days. The intervention discontinued on day 7, and was completed in 4 weeks. Before and after modeling, and after intervention completion, the behavioristics detection was performed using sucrose preference experiment and open field experiment. After intervention, using hematoxylin-eosin (HE) and Nissl staining, the morphology of hippocampal neurons was observed; with Western blot method, the protein expression of GPX4, SLC7A11, Ferritin and acyl-CoA synthetase long-chain family 4 (ACSL4) in hippocampal tissues was detected; with the real-time fluorescence quantitative PCR adopted, the mRNA expression of GPX4, SLC7A11, Ferritin and ACSL4 was detected; and using colorimetry, the hippocampal iron content was determined. RESULTS: After modeling, the sucrose preference rates, the total distance of movement, the standing times and the boxes of horizontal crossing in the model group and the acupuncture group were lower than those in the normal group (P<0.01). After the intervention, the sucrose preference rates, the total distance of movement, the standing times and the boxes of horizontal crossing in the acupuncture group were higher than those in the model group (P<0.01, P<0.05). Compared with the normal group, the number of necrotic cells increased and the number of Nissl bodies decreased in the model group; and when compared with the model group, the neuronal pyknosis and necrosis were ameliorated, the cells were arranged more regularly, the neuronal structure was clear, the matrix was dense, the blood vessels were enriched and the number of Nissl bodies increased in the acupuncture group. In comparison with the normal group, the relative expression of protein and mRNA of hippocampal GPX4, SLC7A11 decreased (P<0.01), it increased in the expression of hippocampal Ferritin and ACSL4 (P<0.01) in the model group. When compared with the model group, in the acupuncture group, the relative expression of protein and mRNA of hippocampal GPX4, SLC7A11 was elevated (P<0.01, P<0.05), it was dropped for hippocampal Ferritin and ACSL4 (P<0.01). In the model group, the hippocampal iron content was elevated when compared with that in the normal group (P<0.01); and it was reduced in the acupuncture group when compared with that in the model group (P<0.05). CONCLUSION Tongdu Tiaoshen acupuncture attenuates depression-like behaviors in the depression rats, which may be related to regulating SLC7A11/GPX4 pathway and inhibiting neuronal ferroptosis in the hippocampus.
Animals ; Ferroptosis ; Male ; Hippocampus/cytology* ; Rats, Sprague-Dawley ; Rats ; Depression/enzymology* ; Phospholipid Hydroperoxide Glutathione Peroxidase/genetics* ; Acupuncture Therapy ; Neurons/metabolism* ; Humans ; Acupuncture Points ; Amino Acid Transport System y+/genetics* ; Glutathione Peroxidase/genetics*

OBJECTIVE: To observe the effect of electroacupuncture at "Sishencong" (EX-HN1) and "Fengchi" (GB20) on hippocampal neuronal ferritinophagy mediated by the nuclear receptor coactivator 4 (NCOA4)/ferritin heavy chain 1 (FTH1) signaling pathway in vascular dementia (VD) rats, and to explore the potential mechanisms of electroacupuncture for VD. METHODS: A total of 60 male rats of SPF grade were randomly divided into a blank group (12 rats), a sham surgery group (12 rats) and a modeling group (36 rats). In the modeling group, the modified 4-vessel occlusion method was used to establish the VD model. The 24 successfully modeled rats were randomly divided into a model group and an electroacupuncture group, with 12 rats in each group. In the electroacupuncture group, electroacupuncture was applied at left and right "Sishencong" (EX-HN1), and bilateral "Fengchi" (GB20), with continuous wave, in frequency of 2 Hz and current intensity of 1 mA, 30 min a time, once daily for 21 consecutive days. The learning and memory abilities were assessed using the Morris water maze test before modeling, after modeling and after intervention, as well as the novel object recognition test after intervention. After intervention, the neuronal morphology in the hippocampus was observed by Nissl staining; the iron deposition was observed by Prussian blue staining; the reactive oxygen species (ROS) level was detected by dihydroethidium (DHE) fluorescence staining; the levels of iron, malondialdehyde (MDA) and superoxide dismutase (SOD) in the hippocampal tissue were measured by the colorimetric assay, TBA method, and WST-1 method, respectively; the positive expression of NCOA4, FTH1 and glutathione peroxidase 4 (GPX4) was detected by immunohistochemistry; the protein expression of NCOA4, FTH1, GPX4, and the ratio of microtubule-associated protein 1 light chain 3B (LC3B) Ⅱ/Ⅰ in the hippocampus were detected by Western blot. RESULTS: Compared with the sham surgery group, in the model group, the escape latency was prolonged, and the number of platform crossings reduced (P<0.01), the recognition index (RI) was decreased (P<0.01); the hippocampal neurons displayed a blurred laminar structure, disorganized cellular arrangement, and the number of Nissl bodies was decreased (P<0.01); the percentage of iron deposition area in the hippocampus was increased (P<0.01); in the hippocampus, the levels of ROS, iron, MDA, and the protein expression of NCOA4, as well as the LC3B Ⅱ/Ⅰ ratio were increased (P<0.01), the SOD level, and the protein expression of FTH1 and GPX4 were decreased (P<0.01). Compared with the model group, in the electroacupuncture group, the escape latency was shortened and the number of platform crossings was increased (P<0.01), the RI was increased (P<0.01); the hippocampal neurons exhibited more regular morphology, better-organized cellular structure, and the number of Nissl bodies was increased (P<0.05); the percentage of iron deposition area in the hippocampus reduced (P<0.01); in the hippocampus, the levels of ROS, iron, MDA, and the protein expression of NCOA4, as well as the LC3B Ⅱ/Ⅰ ratio were decreased (P<0.01, P<0.05), the SOD level, and the protein expression of FTH1 and GPX4 were increased (P<0.01). CONCLUSION Electroacupuncture at "Sishencong" (EX-HN1) and "Fengchi" (GB20) can improve learning and memory abilities in VD rats, and its mechanism may be associated with the regulation of the hippocampal NCOA4/FTH1 signaling pathway, inhibition of ferritinophagy, and alleviation of oxidative stress damage.
Animals ; Electroacupuncture ; Dementia, Vascular/genetics* ; Male ; Rats ; Signal Transduction ; Humans ; Memory ; Rats, Sprague-Dawley ; Nuclear Receptor Coactivators/genetics* ; Ferritins/genetics* ; Learning ; Hippocampus/metabolism* ; Acupuncture Points

OBJECTIVE: To observe the effects of Tongdu Tiaoshen acupuncture (for unblocking the obstruction in the governor vessel and regulating the spirit) on depression-like behavior and the hippocampal Endophilin A1/reactive oxygen species (ROS) pathway in the chronic unpredictable mild stress (CUMS) model rats, and explore the mechanism of this therapy for depression. METHODS: Forty-eight male SD rats of SPF grade were randomly divided into a normal group (n=12) and a modeling group (n=36). In the modeling group, CUMS was performed to establish depression model. The successfully-modeled rats were randomized into a model group, a Tongdu Tiaoshen acupuncture group (referred to as the acupuncture group), and a fluoxetine group, with 12 rats in each group. In the acupuncture group, "Baihui" (GV20), "Shenting" (GV24), "Shuigou" (GV26) and "Dazhui" (GV14) were stimulated with acupuncture. This intervention measure was delivered once a day, continuously for 6 days; it was discontinued on day 7 and was completed in 28 days. In the fluoxetine group, intragastric administration was done with fluoxetine solution (2.1 mg/kg), once a day, and for 28 consecutive days. Before and after modeling, and after intervention completion, the body mass, sucrose preference rate and the total distance of movement and the boxes of horizontal crossing in the open field experiment were observed in each group. After intervention, using HE staining, the hippocampal neuron morphology was observed; using Nissl staining, the hippocampal Nissl body number was counted. The hippocampal mitochondria was observed under transmission electron microscopy. The average fluorescence intensity of ROS in hippocampal was determined using flow cytometry. With Western blot method, the protein expression of Endophilin A1, growth associated protein 43 (GAP-43), and brain-derived neurotrophic factor (BDNF) in hippocampal was detected; and with RT-qPCR method, the mRNA expression of Endophilin A1, GAP-43, and BDNF was recorded. Using the immunofluorescence, the average fluorescence intensity of Endophilin A1, GAP-43, and BDNF in hippocampal tissue was determined. RESULTS: Compared with the normal group, in the model group, the body mass, sucrose preference rate, and the total distance of movement and the boxes of horizontal crossing in the open field experiment decreased (P<0.01); the hippocampal neuronal structure was unclear, the matrix was relatively loose, and the number of Nissl body decreased (P<0.01); mitochondrial structure was disarranged, the outer membrane was ruptured, mitochondrial cristae was irregular or missed; the average fluorescence intensity of ROS in hippocampal tissue, the protein and mRNA expression and the average fluorescence intensity of Endophilin A1 in hippocampal tissue increased (P<0.01), while the protein and mRNA expression of GAP-43 and BDNF and its average fluorescence intensity decreased (P<0.01). Compared with the model group, the acupuncture group and the fluoxetine group showed the increase in body mass, sucrose preference rate, the total distance of movement and the boxes of horizontal crossing in the open field experiment (P<0.05, P<0.01); the hippocampal neuronal structure became relatively clear, the matrix was relatively dense, and the number of Nissl body was elevated (P<0.01); mitochondrial structure got normal and disarranged slightly, the average fluorescence intensity of ROS in hippocampal tissue, the protein and mRNA expression and the average fluorescence intensity of Endophilin A1 in hippocampal tissue were reduced (P<0.01), while the protein and mRNA expression of GAP-43 and BDNF and the average fluorescence intensity rose (P<0.01, P<0.05). Compared with the fluoxetine group, the acupuncture group presented the increase in the average fluorescence intensity of ROS, the protein expression and the average fluorescence intensity of Endophilin A1, the protein expression of GAP-43 and the mRNA expression of BDNF (P<0.01, P<0.05), and the decrease of the protein expression and the average fluorescence intensity of BDNF, the mRNA expression of Endophilin A1, and the average fluorescence intensity of GAP-43 (P<0.01, P<0.05). CONCLUSION Tongdu tiaoshen acupuncture alleviates depression-like behaviors in CUMS model rats and protects hippocampal neurons, which may be related to suppressing Endophilin A1/ROS signaling pathway and attenuating oxidative stress reactions.
Animals ; Male ; Hippocampus/metabolism* ; Acupuncture Therapy ; Rats, Sprague-Dawley ; Rats ; Depression/psychology* ; Humans ; Reactive Oxygen Species/metabolism* ; Disease Models, Animal ; Acupuncture Points

OBJECTIVE: To observe the effect of Huayu Tongluo moxibustion on the NOD-like receptor protein 3 (NLRP3)/cysteine-aspartic acid protease-1 (Caspase-1)/gasdermin D (GSDMD) signaling pathway in rats with vascular dementia (VD), and to explore its mechanism in improving learning and memory ability and alleviating neuronal injury in the hippocampal CA1 region. METHODS: A total of 80 SPF-grade male Wistar rats were included. Three rats were excluded based on the Morris water maze test. From the remaining rats, 12 were randomly selected as the sham operation group. The rest were used to establish VD models via modified bilateral common carotid artery ligation. Thirty-six successfully modeled rats were randomly divided into a model group, a medication group, and a moxibustion group, with 12 rats in each group. The medication group was treated with nimodipine solution (12 mg/kg) via gavage. The moxibustion group was treated with Huayu Tongluo moxibustion. The suspended moxibustion was applied at Shenting (GV24) and Dazhui (GV14), and aconite cake-separated moxibustion was applied at Baihui (GV20), with each acupoint treated for 20 min. All treatments were administered once daily for 21 consecutive days. Before and after modeling, and after intervention, the Morris water maze test was used to assess cognitive function. After intervention, the activation and morphology of microglia in the hippocampal CA1 region were observed by immunofluorescence. Ultrastructure of hippocampal CA1 neurons was examined by transmission electron microscopy. Western blot was used to detect protein expression of NLRP3, apoptosis-associated speck-like protein (ASC), Caspase-1, GSDMD, and interleukin-1β (IL-1β) in the hippocampal CA1 region. ELISA was used to detect the content of IL-6, IL-8, and tumor necrosis factor-α (TNF-α) in the hippocampal CA1 region. RESULTS: Compared with the sham operation group, the model group showed longer mean escape latency (P<0.01) and fewer platform crossings (P<0.01); the microglial processes in the hippocampal CA1 region were thickened, cytoplasm was hypertrophic, and relative fluorescence intensity of ionized calcium-binding adapter molecule 1 (IBA-1) was increased (P<0.05); the neuronal ultrastructure in the CA1 region was severely damaged, rough endoplasmic reticulum was swollen, mitochondria were deformed and swollen, some cristae were ruptured or dissolved, showing vacuolar changes; the protein expression of NLRP3, ASC, Caspase-1, GSDMD, and IL-1β, as well as levels of IL-6, IL-8, and TNF-α were significantly elevated (P<0.001). Compared with the model group, both the medication group and the moxibustion group showed shortened mean escape latency (P<0.01) and increased platform crossings (P<0.01); the microglial processes were thinner, and IBA-1 fluorescence intensity was decreased (P<0.05); the neuronal ultrastructure in the CA1 region was partially improved; the protein expression of NLRP3, ASC, Caspase-1, GSDMD, and IL-1β, and levels of IL-6, IL-8, and TNF-α were significantly reduced (P<0.001). Compared with the medication group, the moxibustion group showed shortened mean escape latency (P<0.05) and more platform crossings (P<0.05); the IBA-1 fluorescence intensity was decreased (P<0.05); the neuronal ultrastructure in the CA1 region was improved; the protein expression of NLRP3, ASC, Caspase-1, GSDMD, and IL-1β, as well as levels of IL-6, IL-8, and TNF-α, were significantly lower (P<0.001). CONCLUSION The Huayu Tongluo moxibustion could enhance learning and memory abilities in VD rats, inhibit excessive activation of microglia, and alleviate neuronal injury in the hippocampal CA1 region. Its mechanism may involve modulation of the NLRP3/Caspase-1/GSDMD signaling pathway, reduction of inflammatory responses.
Animals ; Male ; Dementia, Vascular/physiopathology* ; Rats ; Signal Transduction ; Moxibustion ; Rats, Wistar ; CA1 Region, Hippocampal/injuries* ; NLR Family, Pyrin Domain-Containing 3 Protein/genetics* ; Caspase 1/genetics* ; Memory ; Humans ; Neurons/metabolism* ; Learning

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Hegu" (LI4) and "Taichong" (LR3) on DNA methylation of the solute carrier family 6 member 4 (SLC6A4) gene promoter region in the hippocampus of depressed rats, and to explore the potential antidepressant mechanism of EA. METHODS: Thirty male Sprague-Dawley rats were randomly divided into a blank group, a model group, a medication group, a 5-Azacytidine (5-AZA) group, and an EA group, 6 rats in each group. Depression models were established in the model group, the medication group, the 5-AZA group, and the EA group using chronic unpredictable mild stress (CUMS) combined with solitary housing. The medication group was treated with intragastric administration of fluoxetine hydrochloride capsules; the 5-AZA group was treated with intraperitoneal injection of 5-AZA; the EA group was treated with EA at bilateral "Hegu" (LI4) and "Taichong" (LR3), with disperse-dense wave, frequency of 2 Hz/100 Hz, and intensity of 1-1.2 mA, 20 min each session. All the treatment was given in three groups once daily for 21 consecutive days. Behavioral changes were evaluated by sucrose preference test, open field test, and novelty-suppressed feeding test. Serum levels of serotonin (5-HT), dopamine (DA), and norepinephrine (NE) were measured by ELISA. The expression of SLC6A4 and 5-HT1AR protein and mRNA in hippocampus was detected by Western blot and real-time quantitative PCR, respectively. DNA methylation status of the SLC6A4 promoter region in hippocampal tissue was analyzed by bisulfite sequencing PCR (BSP). RESULTS: Compared with the blank group, the model group showed decreased sucrose preference, reduced total locomotor distance, and prolonged latency to feeding (P<0.05), decreased serum 5-HT, DA, and NE levels (P<0.05), downregulated hippocampal SLC6A4 and 5-HT1AR protein and mRNA expression (P<0.05), and increased CpG site methylation rate of the SLC6A4 promoter region (P<0.05). Compared with the model group, the medication group, the 5-AZA group, and the EA group exhibited increased sucrose preference, increased total locomotor distance, shortened latency to feeding (P<0.05), elevated serum 5-HT, DA, and NE levels (P<0.05), upregulated hippocampal SLC6A4 and 5-HT1AR protein and mRNA expression (P<0.05), and reduced CpG site methylation rate of the SLC6A4 promoter (P<0.05). Compared with the medication group and the 5-AZA group, the EA group showed higher sucrose preference, greater total locomotor distance, shorter latency to feeding (P<0.05), and increased serum DA and NE levels (P<0.05). CONCLUSION EA could improve depressive behaviors in depressed rat models. The underlying mechanism may involve inhibition of SLC6A4 hypermethylation in the hippocampus on the serotonergic system, upregulation of SLC6A4 and 5-HT1AR protein and mRNA expression, and elevation of monoamine neurotransmitters such as 5-HT.
Animals ; Electroacupuncture ; Male ; Hippocampus/metabolism* ; Rats, Sprague-Dawley ; Rats ; Acupuncture Points ; DNA Methylation ; Depression/metabolism* ; Promoter Regions, Genetic ; Serotonin Plasma Membrane Transport Proteins/metabolism* ; Humans

The hippocampus, a major component of the limbic system, is the most important region related to emotion regulation and memory processing. Cognitive impairment and depressive symptoms observed in Alzheimer's disease (AD) patients may be attributed to hippocampal damage caused by amyloid β-protein (Aβ). Our previous studies have demonstrated that a steroid sulfatase inhibitor DU-14 can enhance hippocampal synaptic plasticity and spatial memory abilities in a chronic AD murine model by counteracting the toxic effects of Aβ. However, limited experimental evidence exists regarding the efficacy of steroid sulfatase inhibitor on depressive symptoms in AD animal models. In this study, we investigated the effects of DU-14 on depressive symptoms and theta-band neuronal oscillations in rats with intrahippocampal injection of Aβ_1-42 using various behavioral tests such as sucrose preference test, tail suspension test, forced swimming test, and in vivo hippocampal local field potential (LFP) recording. The results demonstrated that, in comparison to the control group: (1) rats in the Aβ group exhibited a decrease in sucrose preference, indicating a loss of interest in pleasurable activities; (2) rats in the Aβ group displayed aggravated depressive-like behavior characterized by prolonged immobility time during tail suspension and forced swimming tests; (3) Aβ disrupted the induction of theta rhythm via tail pinch stimulation, and resulted in a significant reduction in peak power of theta rhythm. In contrast to the Aβ group, pretreatment with DU-14 resulted in: (1) a significant improvement in Aβ-induced anhedonia, as evidenced by increased sucrose preference; (2) significant alleviation of Aβ-induced despair and depressive-like behaviors, reflected by reduced immobility time during tail suspension and forced swimming tests; (3) successful mitigation of Aβ-mediated inhibition on bilateral hippocampal theta rhythm. These findings indicate that steroid sulfatase inhibitor DU-14 can counteract neurotoxicity induced by Aβ, and prevent Aβ-induced depressive-like behavior and suppression of theta rhythm.
Animals ; Amyloid beta-Peptides/toxicity* ; Rats ; Depression/physiopathology* ; Theta Rhythm/drug effects* ; Hippocampus/physiopathology* ; Male ; Rats, Sprague-Dawley ; Alzheimer Disease/physiopathology* ; Steryl-Sulfatase/antagonists & inhibitors* ; Peptide Fragments ; Behavior, Animal/drug effects*

Dopamine, as a catecholamine neurotransmitter widely distributed in the central nervous system, is involved in physiological functions such as motivation, arousal, reinforcement, and movement through various dopamine signaling pathways. The hippocampus receives dopaminergic neuron projections from regions such as the ventral tegmental area, locus coeruleus, and substantia nigra. Through D1-like and D2-like receptors, dopamine exerts significant regulatory effects such as spatial navigation, episodic memory, fear, anxiety, and reward. This review mainly summarizes the research progress on the functions of dopamine in the hippocampus from aspects including the sources of dopamine, receptor distribution and function, and the association of hippocampal dopamine system dysregulation with neurodegenerative diseases. The aim is to provide insights into the involvement of the dopamine system in hippocampal functions and the diagnosis and treatment of related diseases.
Hippocampus/physiology* ; Dopamine/physiology* ; Humans ; Animals ; Receptors, Dopamine D2/physiology* ; Memory/physiology* ; Signal Transduction/physiology* ; Neurodegenerative Diseases/physiopathology*

To study the ameliorative effect of Eucommiae Cortex extract on spatial learning disabilities in APP/PS1 double-transgenic mice and explore its relationship with estrogen receptor β(ERβ)/c-Jun N-terminal kinase(JNK) signaling pathway, sixty 3-month-old male APP/PS1 mice were randomly divided into a model group, an anti-brain failure capsule group(0.585 g·kg~(-1)), a donepezil hydrochloride group(0.65 mg·kg~(-1)), and a Eucommiae Cortex extract group(1.3 g·kg~(-1)), and 15 C57BL/6 mice of the same genetic background were set as WT control group. The learning and memory ability of mice was assessed by the Morris water maze test(MWM), the passive avoidance test(PAT), and the novel object recognition test(NOR). The histomorphological and cellular ultrastructural features of the hippocampal region of the mice were observed by hematoxylin-eosin(HE) staining and transmission electron microscopy(TEM); the molecular docking validation of the key active ingredients and the key targets was performed by using AutoDock Vina software, and the immunohistochemical method(IHC) was used to detect the ERβ expression in the dentate gyrus(DG) area of mouse hippocampus. Western blot(WB) was utilized to detect the expression of ERβ, p-JNK, and JNK in mouse hippocampal area. Compared with those in the WT control group, the results of behavioral experiments showed that the latency of the mice in the model group was significantly increased, the number of platform traversals, and the target quadrant residence time were significantly decreased in the MWM. The evasion latency was significantly reduced, and the number of errors was significantly increased in the PAT. The index of recognition of novel objects was significantly reduced in the NOR. The results of HE staining indicated that the hippocampal area of mice in the model group showed a decrease in the number of neurons, disorganization of pyramidal cell arrangement, nucleus consolidation, and other changes. TEM results showed that some neuronal nuclei in the hippocampal area had a consolidated state, slightly thickened and aberrant nuclear membranes, and fewer intracytoplasmic nidus bodies; the IHC results showed that the expression of ERβ in the hippocampal DG area of the mice was reduced. The WB results showed that the ERβ expression in the hippocampal tissue was decreased, and the p-JNK/JNK level was elevated. Compared with the model group, the Eucommiae Cortex extract group showed a significant decrease in latency, and increase in number of platform traversals and target quadrant residence time in the MWM, a significant increase in evasion latency and decrease in number of errors in the PAT, and a significant increase in the index of recognition of novel objects in the NOR. In addition, there was an increase in the number of neurons in the hippocampal area of mice. The pyramidal cells tended to be arranged in an orderly manner; the nuclei of neurons in the hippocampal area were in a better state; the expression of ERβ in the hippocampal DG area of the mice was elevated; the expression of ERβ in the hippocampal tissue was elevated, and the level of p-JNK/JNK was reduced. The effects of donepezil hydrochloride group and anti-brain failure capsule on APP/PS1 mice in terms of behavioral, HE, and TEM indexes were similar to those of Eucommiae Cortex extract, and there was no significant difference between donepezil hydrochloride group and the model group in IHC and WB experiments, and the results of molecular docking indicated that the estrogen-like components in Eucommiae Cortex extract were tightly bound to ERβ. In conclusion, the binding of Eucommiae Cortex extract to estrogen receptors, regulation of ERβ expression, and activation of ERβ/JNK signaling pathway may be one of the key mechanisms by which it improves the learning and memory ability of APP/PS1 mice.
Animals ; Male ; Mice ; Mice, Transgenic ; Memory/drug effects* ; Mice, Inbred C57BL ; Estrogen Receptor beta/genetics* ; Eucommiaceae/chemistry* ; Alzheimer Disease/psychology* ; Amyloid beta-Protein Precursor/metabolism* ; Presenilin-1/metabolism* ; Humans ; MAP Kinase Signaling System/drug effects* ; Drugs, Chinese Herbal/administration & dosage* ; Hippocampus/metabolism* ; Maze Learning/drug effects* ; Learning/drug effects*

This study explores the mechanism of Guben Jiannao Liquid on Alzheimer's disease(AD) by regulating autophagy based on the liver kinase B1(LKB1)/adenosine monophosphate-activated protein kinase(AMPK)/mammalian target of rapamycin(mTOR) pathway. Male SD rats were randomly divided into the blank group, model group, low-dose and high-dose groups of Guben Jiannao Liquid, and rapamycin group, with 10 rats in each group. Except for the blank group, all other groups of rats were injected bilaterally in the hippocampus with β-amyloid(Aβ)_(1-42) to establish the AD model. The low-dose(6.21 g·kg~(-1)) and high-dose(12.42 g·kg~(-1)) groups of Guben Jiannao Liquid and rapamycin group(1 mg·kg~(-1)) were given the corresponding drugs by gavage, and the blank and model groups were given an equal volume of saline by gavage for four weeks. Morris water maze was used to test the learning and memory ability of rats in each group; hematoxylin-eosin(HE) and Nissl staining were used to observe the morphological and quantitative changes of neurons and Nissl bodies in the CA1 region of rat hippocampus; immunohistochemistry was utilized to detect Aβ-positive cell expression in the CA1 region of rat hippocampus; transmission electron microscopy was employed to observe ultrastructural changes in rat hippocampal tissue, and Western blot was used to examine the protein expression levels of LKB1, p-AMPK/AMPK, p-mTOR/mTOR, Beclin1, p62, and LC3-Ⅱ in the hippocampal tissue of the rats. The results showed that compared with those in the blank group, rats in the model group had elevated evasion latency and decreased number of platform transversal and residence time in the platform quadrant. The number of neurons in the hippocampal area was reduced, and the morphology was impaired. The average integral optical density value of Aβ-positive cells was elevated; the expression levels of LKB1, p-AMPK/AMPK, Beclin1, and LC3-Ⅱ were decreased, and the expression levels of p-mTOR/mTOR and p62 were increased. Compared with those in the model group, rats in the low-dose and high-dose groups of Guben Jiannao Liquid had shorter evasion latency, higher number of platform transversal, longer residence time in the platform quadrant, increased number of neurons, decreased expression of Aβ-positive cells and average integral optical density values, and increased number of autophagic lysosomes in hippocampal tissue. The expression levels of LKB1, Beclin1, and LC3-Ⅱ were elevated in the hippocampus of rats in the low-dose group of Guben Jiannao Liquid. The expression levels of LKB1, p-AMPK/AMPK, Beclin1, and LC3-Ⅱ were elevated in the hippocampal tissue of rats in the high-dose group of Guben Jiannao Liquid, and the expression levels of p-mTOR/mTOR and p62 were decreased. The findings suggest that Guben Jiannao Liquid can improve cognitive impairment in AD rats, and its mechanism of action may be related to the activation of the LKB1/AMPK/mTOR signaling pathway and the up-regulation of autophagy level.
Animals ; Alzheimer Disease/physiopathology* ; Male ; TOR Serine-Threonine Kinases/genetics* ; Autophagy/drug effects* ; Rats, Sprague-Dawley ; Protein Serine-Threonine Kinases/genetics* ; AMP-Activated Protein Kinases/genetics* ; Rats ; Drugs, Chinese Herbal/administration & dosage* ; Signal Transduction/drug effects* ; AMP-Activated Protein Kinase Kinases ; Humans ; Hippocampus/metabolism*