Advances in the application of 5×FAD transgenic mice in Alzheimer's disease research / 中国实验动物学报

Transgenic 5 × FAD mice are APP/PS1 transgenic mice carrying five familial Alzheimer's disease(AD)gene mutations.Beta-amyloid precursor protein(amyloid precursor protein,APP)expression is related to the K670N/M671L(Swedish),1716V(Florida),and V7171(London)mutations,and presenilin 1(PSI)is affected by the M146L and L286V mutations.5 × FAD mice express high levels of β-amyloid in the brain at 1.5 months old,and neuritic plaques began to appear at 2 months old.The pathological phenotypes of 5 × FAD mice include amyloid plaque aggregation,neuronal loss,gliosis,and memory dysfunction,while their biological characteristics include changes in the formation of brain β-amyloid plaques,hyperphosphorylation of Tau protein,synaptic dysfunction,neuroinflammatory response,mitochondrial dysfunction,blood-brain barrier injury,neuronal injury,endoplasmic reticulum stress,and eye lesions.As a classic animal model of AD,5 × FAD transgenic mice can simulate the neuropathological process and behavioral manifestations of late-stage AD in humans,and these mice are thus widely used in research into the pathogenesis of AD and the development of new drugs.In this review,we summarize the model construction,biological background,and biological characteristics of 5 x FAD transgenic mice,and the development and application of drugs for the prevention and treatment of AD,to provide references for the application of 5 x FAD transgenic transgenic mice in AD research.

Effects of 5-Aza-CdR on hippocampal neurogenesis in mice via the Notch1 pathway / 中国比较医学杂志

Objective To investigate the effect of 5-Aza-CdR on Notch1 pathway and neural regeneration and to explore the effects of 5-Aza-CdR on learning memory ability in mice by exploring active avoidance behavior.Methods Sixty 6～8-week-old SPF-grade ICR male mice were divided into two groups.5-Aza-CdR was administered to one group of mice via lateral ventricular injection,while the control group was injected with bovine serum albumin.Notch1 and HES1 mRNA and protein expression levels were detected by Real-time PCR and Western blot 24 hours after injection;5-bromo-2'-deoxyuridine-positive cells were observed by laser confocal microscopy,and Notch1 expression in hippocampal dentate gyrus was viewed with laser confocal microscopy.Notch1 methylation changes were detected by ethylation-specific PCR,and learning and memory behaviors of mice were assessed by passive avoidance tests and shuttle avoidance assays.Results Injection of 5-Aza-CdR increased hippocampal Notch1 pathway activity,promoted neuronal regeneration in the DG region,decreased methylation levels in the Notch1 promoter region,and enhanced the ability of mice to perform active avoidance behavior.Conclusions The effect of 5-Aza-CdR on active avoidance behavior may be related to the influence of hippocampal neural regeneration through the Notch 1 pathway.

Effects of repetitive transcranial magnetic stimulation on learning-memory and synaptic plasticity in hippocampus of rats with post-stroke sleep deprivation / 中华行为医学与脑科学杂志

Objective:To investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on learning-memory and the expression of synaptic plasticity proteins in hippocampus of rats with post-stroke sleep deprivation.Methods:A total of 28 SPF grade healthy male Wistar rats with 8-week old were randomly divided into four groups (control group, sham operation group, model group and rTMS group) according to random number table method, with 7 rats in each group. The rats in the model group and the rTMS group were treated with middle cerebral artery occlusion and p-chlorophenylalanine intraperitoneal injection to establish the post-stroke sleep deprivation model. The rats in the rTMS group were treated with rTMS intervention for consecutive 14 days after modeling. The rats in the sham operation group were only separated arteries but not ligated and inserted. The rats in control group were fed normally. The open field test (OFT) was used to observe the autonomous behavior of rats.The water maze test(WMT) was used to observe the spatial learning and memory ability of rats.The content of tyrosine kinase receptor type B(TrkB) in hippocampus was detected by Western blot.The expressions of brain-derived neurotrophic factor(BDNF) and immediate early gene c-fos in hippocampus were detected by immunofluorescence.The morphology and structure of neurons in hippocampus were observed by optical microscopy and transmission electron microscopy. SPSS 21.0 software was used for statistical analysis, and repeated measurement ANOVA was used for the escape latency data, one-way ANOVA was used for the comparison of other data among multiple groups, and LSD test was used for further pairwise comparison.Results:(1) The OFT results showed that there were statistical differences in the numbers of crossing squares, upright times and total points of rats in the four groups after intervention ( F=27.638, 10.425, 30.690, all P<0.001). The numbers of crossing squares ((72.71±10.10)), upright times ((6.57±0.87)times) and total points ((79.29±10.03) points) of rats in rTMS group were all higher than those in model group after intervention ((43.71±6.96), (3.43±0.65)times, (47.14±6.82)points) (all P<0.05). As for the escape latency of WMT among the four groups of rats, the interaction effect was not significant( F=1.108, P=0.37), and the time main effect( Ftime=27.295, Ptime<0.01) and group main effect ( Fgroup=8.691, Pgroup<0.01) were significant after rTMS intervention.On the 3rd and 4th day, the escape latency of rTMS group rats was lower than that of the model group (both P<0.01). There were statistically significant differences in the numbers of crossing platform, swimming distance and residence time in target quadrant of rats in the four groups after intervention( F=8.569, 3.308, 3.547, all P<0.05). The numbers of crossing platform ((2.00±0.31)times), swimming distance in target quadrant ((196.95±24.57) cm) and residence time ((17.72±1.36)s) of rats in rTMS group were all higher than those in model group after intervention ((1.57±0.30)times, (146.61±4.79) cm, (13.58±0.98)s)(all P<0.05). (2)Optical microscopy and transmission electron microscopy showed that the hippocampal cells arranged irregularly, the organelles' integrity was destroyed in the model group compared with the normal control group. In rTMS group the arrangement and structure of nerve cells in the hippocampus were improved after rTMS intervention. (3) The immunofluorescence results showed that c-fos (1.49±0.09) and BDNF (0.84±0.06) in the hippocampus of rats in rTMS group were both higher than those in model group ((1.24±0.12), (0.48±0.08))(both P<0.05). The Western blot results showed that the expression level of TrkB (1.81±0.03) in the hippocampus of rats in rTMS group was higher than that in model group (0.96±0.02) ( P<0.05). Conclusion:The rTMS can improve the learning-memory ability and autonomous capacity of rats with post-stroke sleep deprivation, which may be related to promoting the expression of c-fos, BDNF and TrkB in hippocampus tissue.

Effects of aerobic exercise on learning and memory functions, hippocampal synaptic plasticity and the adiponectin signaling pathway in diabetic rats / 中华老年医学杂志

Objective:To explore the effects of aerobic exercise on learning and memory functions, hippocampal synaptic plasticity and the ADPN signaling pathway in diabetic rats.Methods:6-week-old male SD rats were randomly divided into a blank control group(NC group)and a high-fat diet group, and a rat model for diabetes was induced by feeding rats in the high-fat diet group with a high-fat diet combined with intraperitoneal instillation of low-dose streptozotocin(STZ)for 5 weeks.Rats in the high-fat diet group were further divided into a diabetic group(DC group)and a diabetic aerobic exercise group(DM group)after successful establishment of the model.Rats in the DM group were subjected to aerobic exercise for eight weeks and then the Morris water maze test was conducted to assess learning and memory functions, relevant serum markers were measured, Golgi staining was used to examine synaptic changes in the hippocampus, and Western blot was carried out to detect hippocampal protein expression levels of adiponectin(ADPN), AMP-activated protein kinase(AMPK), glucose transporter 4(GLUT4), synaptic plasticity-related protein synaptophysin(SYN)and postsynaptic density protein 95(PSD-95)for rats in each group.Results:Serum FBG and HBA1c in diabetic rats were markedly significantly decreased after 8 weeks of aerobic exercise( P<0.01), and serum ADPN and insulin were significantly increased after 8 weeks of aerobic exercise( P<0.05).When test results from the three groups of rats compared, the F value was 69.248 for FBG, 6.740 for INS, 7.017 for HBA1C and 14.315 for serum ADPN.The results of the water maze test and hippocampal Golgi staining showed that the escape latency of diabetic rats was highly significantly decreased after 8 weeks of aerobic exercise( P<0.01).The platform crossing times, the number of dendritic branches and the dendritic spine density in the hippocampal CA3 region of diabetic rats were significantly increased after 8 weeks of aerobic exercise( P<0.05).When results from the three groups of rats were compared, the F value was 13.934 for escape latency, 5.864 for platform crossing times, 9.307 and 6.734 for the number of dendritic branches and the density of dendritic spine in hippocampal CA3 region.Hippocampal PSD-95, SYN, ADPN, p-AMPK, and GLUT4 protein expression levels of diabetic rats were significantly increased( P<0.05)after 8 weeks of aerobic exercise.When results from the three groups of rats were compared, the F value was 15.137 for SYN, 5.415 for PSD-95, 9.687 for ADPN, 27.761 for GLUT4, and 9.298 for p-AMPK. Conclusions:Eight weeks of aerobic exercise can improve the learning and memory functions of diabetic rats, and the mechanisms may be related to exercise-induced hippocampal ADPN/AMPK/GLUT4 signaling activation in rats, leading to enhanced synaptic plasticity in the hippocampus.

Effects of Shiquan Dabu Decoction on cognitive impairment in a mouse model of Alzheimer's disease through regulation of synaptic function / 中成药

AIM To explore the effects of Shiquan Dabu Decoction on the synaptic function and cognitive impairment in a mouse model of Alzheimer's disease(AD).METHODS Sixty mice were randomly divided into the control group,the model group,the memantine group(5 mg/kg)and the high,medium and low dose Shiquan Dabu Decoction groups(6.24,3.12 and 1.56 g/kg),with 10 mice in each group.Except for those of the control group,the mice of other groups underwent their 70-day AD models induction by intraperitoneal injection of D-galactose and gavage feeding of AlCl3,followed by 42-day corresponding dosing of drugs by gavage on the 29th day.The mice had their spatial learning and associative memory detected by Morris water maze test and conditioned fear test;their morphological changes of hippocampal neurons observed by HE staining;their serum SOD activity,MDA level,and SOD,AChE activities and MDA,ACh,TNF-α and IL-1β levels in hippocampus detected by kits;and their PSD-95,Shank3,NR1,NR2A,NR2B,AMPK and p-AMPK protein expressions in hippocampus detected by Western blot.RESULTS Compared with the model group,the high-dose Shiquan Dabu Decoction group displayed improved spatial learning and memory ability and associative memory(P<0.05,P<0.01);reduced pathological damage of hippocampal neurons,decreased levels of oxidative stress and inflammation(P<0.05,P<0.01);enhanced cholinergic transmission(P<0.05,P<0.01),and increased protein expressions of PSD-95,Shank3,NR1,NR2A,NR2B,and p-AMPK in hippocampal tissue(P<0.05,P<0.01).CONCLUSION Shiquan Dabu Decoction can improve the cognitive impairment of in the mouse model of AD,and its mechanism may be related to AMPK activation and synaptic function restoration.

Effects of early-life 6:2 Cl-PFESA exposure on hippocampal AMPA receptor gene expression in offspring mice / 环境与职业医学

Background The compound 6:2 chlorinated polyfluorinated ether sulfonic acids (6:2 Cl-PFESA) has been demonstrated abilities of strong bioaccumulation and placental barrier penetration, and it can also cross the blood-brain barrier. However, the mechanism of its neurodevelopmental toxicity in offspring induced by early-life exposure is still unknown. Objective To explore effects of 6:2 Cl-PFESA on the growth and the α-amino-3-hydroxy-5-methylisoxazole-4-propionic (AMPA) receptor gene expression in the hippocampus of offspring mice by establishing a 6:2 Cl-PFESA exposure animal model. Methods Thirty Kunming pregnant mice were randomly divided into five groups: control group, and 2, 10, 50, and 250 μg·L−1 6:2 Cl-PFESA exposure groups. The treatment groups were exposed to designed doses of 6:2 Cl-PFESA through drinking water from the first day of gestation until the end of lactation. The pups were weaned on postnatal day (PND) 21, and continued to be exposed to 6:2 Cl-PFESA through drinking water. Birth weight and body length of the offspring were recorded. Offspring mice were anesthetized and sacrificed respectively on PND7, PND21, and PND35, then their hippocampus was peeled from harvested brain tissue. The ultrastructure of hippocampus was observed via transmission electron microscopy; and the expression of AMPA receptors GluR1, GluR2, and GluR3 in the hippocampus was evaluated by real-time reverse transcription polymerase chain reaction. The learning and memory ability of the PND35 mice was measured by Morris water maze test before they were sacrificed. Results The birth weights and the lengths of the pups in the 10, 50, and 250 μg·L−1 6:2 Cl-PFESA exposure groups were (2.23±0.36), (1.92±0.20), (1.88±0.31) g, and (33.73±0.98), (32.91±1.30), (32.52±2.07) mm, respectively, which were lower than those in the control group, (2.78±0.35) g and (36.46±2.34) mm (P<0.05), respectively. The results of Morris water maze showed that the escape latencies in the orientation navigation experiment on the 4th day in the 250 μg·L−1 6:2 Cl-PFESA exposure group and on the 5th day in the 10, 50, and 250 μg·L−1 6:2 Cl-PFESA exposure groups were longer than those in the control group (P<0.05). In the space exploration experiment, the times of crossing platform in the 50 and 250 μg·L−1 6:2 Cl-PFESA exposure groups were decreased when compared with the control group (P<0.05), and the time of staying in the target quadrant of the 250 μg·L−1 6:2 Cl-PFESA exposure groups were also decreased (P<0.05). Via transmission electron microscopy, compared with the control group, the postsynaptic density was decreased and the synaptic cleft width was widened on PND35 in the 250 μg·L−1 6:2 Cl-PFESA exposure group. The mRNA expression levels of GluR1, GluR2, and GluR3 in the hippocampus of pups exposed to 250 μg·L−1 6:2 Cl-PFESA during different developmental stages were significantly lower than those in the control group (P<0.05). Except for the 2 μg·L−1 6:2 Cl-PFESA exposure group on PND7, the 6:2 Cl-PFESA exposure inhibited the mRNA expression levels of GluR1, GluR2, and GluR3 in the hippocampus of pups at different developmental stages (P<0.05). Among them, the 6:2 Cl-PFESA exposure during early development resulted in the highest decrease in the expression levels of GluR1 and GluR2 mRNA in the hippocampus of pups on PND7; GluR3 mRNA expression level in the hippocampus of the exposed pups on PND21 showed the maximum inhibitory effect; the expression levels of GluR1, GluR2, and GluR3 mRNA all showed the least decrease in the hippocampus of the exposure groups on PND35. Conclusion Early-life exposure to 6:2 Cl-PFESA may affect the growth and development of offspring mice, alter the hippocampal synaptic structure, and influence the learning and memory abilities, which may be related to their inhibitory effects on the expression levels of AMPA receptor subunits GluR1, GluR2, and GluR3 genes in the hippocampus of offspring mice at various developmental stages.

Mechanism of hippocampal CRHR1 regulating chronic stress-induced learning and memory impairment in early aged mice / 安徽医科大学学报

Objective @# To explore the mechanism of hippocampal corticotropin-releasing hormone ( CRH) receptor type 1 ( CRHR1 ) in chronic stress-induced learning and memory impairment in early aged mice．@*Methods@#C57BL /6J mice aged 12 －14 months were divided into two groups according to gender，and then divided into wild type (WT) group and hippocampal CRHR1 conditional gene knockout (KN) group according to genotype．Mice in each group were randomly divided into control group and stress group，and the stress group was subjected to chronic unpredictable stress ( CUS ) for 30 days． Genotyping of mice was performed using polymerase chain reaction ( PCR) ，agarose gel electrophoresis and real-time fluorescence quantitative PCR (RT-qPCR) ．The new object rec- ognition experiment and Morris Water maze measured learning and memory ability．Golgi-Cox staining was used to observe damage to hippocampal neuronal dendrites． The protein expressions of target protein of rapamycin (mTOR) ，p-mTOR (Ser2448) ，ribosomal protein S6 kinase ( p70S6K) and p-p70S6K ( Thr389 / Thr412 ) were detected by Western blot．Serum levels of corticotropin releasing hormone ( CRH) were measured by ELISA. @*Results @# Compared to mice without chronic stress，the cognitive coefficient of WT stress groups decreased after chron- ic stress，and the difference was statistically significant (P ＜0. 05) ，while there was no significant difference in cognitive coefficient of KN stress groups before and after chronic stress．Compared with the WT stress group，the escape latency of the WT control group was shortened (P＜0. 05) ，and the number of crossing the platform and tar- get quadrant increased (P ＜0. 01) ，and there was no significant difference in the KN groups above． Compared with the WT control group，the WT stress group had a significant reduction in the neuronal complexity in the hipp- ocampal CA1，CA3 and DG regions (P ＜0. 05) and significant reductions in the expression of p-mTOR and p- p70S6K in the hippocampus (P＜0. 05) ．There was no significant difference in the expression of p-mTOR between the KN stress group and the KN control group (P＞0. 05) ，except that the expression of p-mTOR in the hippocam- pus of the female group decreased (P＜0. 05) ．In addition，the serum level of CRH in the stress group was higher than that in the control group (P＜0. 01) ．@*Conclusion @#Hippocampal CRHR1 regulates learning and memory im- pairment and neuronal dendrite damage in early aged mice induced by chronic stress．The mechanism may be that high levels of CRH induced by chronic stress cannot bind to CRHR1 receptor，thereby enhancing the expression of down-regulated mTOR / p70S6K signaling pathway.

Research Progress on Aerobic Exercise Intervention for Learning and Memory Ability in Chronic Cerebral Ischemia / 昆明医科大学学报

Active physical exercise can effectively alleviate the pathological process of chronic cerebral ischemia(CCH)and improve learning and memory ability.This paper reviews the possible biological mechanisms of aerobic exercise to delay the pathological process of chronic cerebral ischemia and improve learning and memory.Previous studies have found that aerobic exercise can improve the neuroprotective effect,enhance the plasticity of hippocampal synapses,improve the activity of the upper and lower pathways of hippocampal tissue,and improve learning and memory ability.However,the intervention effect of aerobic exercise on chronic cerebral ischemia should be fully considered at the intervention time,and the intervention effect is also different.

Effects of Jiaohong Pills and Its Prescription on Scopolamine-induced Alzheimer's Disease Mice / 中国实验方剂学杂志

ObjectiveTo investigate the effects of Jiaohong pills （JHP） and its prescription， Pericarpium Zanthoxyli （PZ） and Rehmanniae Radix （RR） cognitive dysfunction in scopolamine-induced Alzheimer's disease （AD） mice and its mechanism through pharmacodynamic and metabolomics study. MethodThe animal model of AD induced by scopolamine was established and treated with PZ， RG and JHP， respectively. The effects of JHP and its formulations were investigated by open field test， water maze test， object recognition test， avoidance test， cholinergic system and oxidative stress related biochemical test. Untargeted metabolomics analysis of cerebral cortex was performed by ultra-performance liquid chromatography-Quadrupole/Orbitrap high resolution mass spectrometry （UPLC Q-Exactive Orbitrap MS）. ResultThe behavioral data showed that， compared with the model group， the discrimination indexes of the high dose of JHP， PZ and RR groups was significantly increased （P<0.05）. The staging rate of Morris water maze test in the PZ， RR， high and low dose groups of JHP was significantly increased （P<0.05， P<0.01）， the crossing numbers in the PZ， JHP high and low dose groups were significantly increased （P<0.05， P<0.01）； the number of errors in the avoidance test were significantly reduced in the PZ and high-dose JHP groups （P<0.01）， and the error latencies were significantly increased in the JHP and its prescription drug groups （P<0.01）. Compared with the model group， the activities of acetylcholinesterase in the cerebral cortex of the two doses of JHP group and the PZ group were significantly increased （P<0.05， P<0.01）， and the activity of acetylcholinesterase in the high-dose JHP group was significantly decreased （P<0.05）， and the level of acetylcholine was significantly increased （P<0.01）. At the same time， the contents of malondialdehyde in the serum of the two dose groups of JHP decreased significantly （P<0.05， P<0.01）. The results of metabolomics study of cerebral cortex showed that 149 differential metabolites were identified between the JHP group and the model group， which were involved in neurotransmitter metabolism， energy metabolism， oxidative stress and amino acid metabolism. ConclusionJHP and its prescription can antagonize scopolamine-induced cognitive dysfunction， regulate cholinergic system， and reduce oxidative stress damage. The mechanism of its therapeutic effect on AD is related to the regulation of neurotransmitter， energy， amino acid metabolism， and improvement of oxidative stress.

Study on the protective effect of soybean phospholipid powder on nerve injury / 安徽医科大学学报

Objective @#To investigate the protective effects and mechanisms of soybean phospholipid powder on nerve cells in vitro and rats neural tissues.@*Methods @#In the cell experiments , the cytotoxicity of soybean phospholipid powder with different concentrations on mouse microglia cells ( BV2 ) and rat adrenal pheochromocytoma (PC12) cells was ob served by cell counting kit⁃8( CCK⁃8) assay. The effect of soybean phospholipid powder on the NO level of BV2 cells was analyzed by NO determination experiment , and the synaptic growth of PC12 cells was observed under the microscope. In the animal experiment , the cognitive dysfunction of rat was simulated by scopol⁃ ocampal tissue morphology and nerve cell density of scopolamine model mice were ob served by hematoxylin ⁃eosin staining (HE) staining.@*Results @#Soybean phospholipid powder had no obvious cytotoxicity on BV2 cells and PC12 cells within the concentration of 1 000 μg/ml. Compared with the control group , the NO secretion of BV2 cells pretreated with soybean phospholipid powder significantly decreased (P < 0. 01) , and the neuronal synapse growth of PC12 cells significantly increased (P < 0. 01) . In comparison to the model group , soybean phospholipid powder significantly improved the learning and memory ability of scopolamine model rats (P < 0. 05) , reduced the neuronal damage in dentate gyrus (DG) , cornu ammonis3 (CA3) , cornu ammonis1 (CA1) areas of hippocampus , and increased the density of nerve cells (P < 0. 001) .@*Conclusion @#Soybean phospholipid powder can play a neuroprotective role by reducing neuroinflammation and promoting neuronal synapse growth at the cellular level , and improve the learning and memory ability of rats with cognitive impairment , reduce hippocampal tissue damage.

Intervention effect of HSP60 on learning and memory impairment induced by combined exposure to lead and hypertension in mice / 中国职业医学

ObjectiveTo investigate the intervention effect of heat shock protein 60 (HSP60) on learning and memory impairment induced by combined exposure to lead and hypertension in mice, and the relative mechanism of triggering receptor expressed on myeloid cells 2 (TREM2). Methods Specific pathogen-free C57BL/6J male mice were randomly divided into control group, hypertension group, lead-exposed group and lead-exposed + hypertension group, or into control group, heat shock protein 60 (HSP60) control group, lead-exposed + hypertension group and HSP60 intervention group, with 10 mice in each group. Mice of hypertension group and lead-exposed + hypertension group were intraperitoneally injected with angiotensin Ⅱ at a dose of 0.5 mg/(kg·d) for seven consecutive days to induce hypertension model. Mice of the lead-exposed group, lead-exposed + hypertension group, and HSP60 intervention group were given lead acetate drinking water with a mass concentration of 250.0 mg/L, while mice in the control group, hypertension group, and HSP60 control group were given purified water for 12 weeks. Mice of the HSP60 control group and HSP60 intervention group were intraperitoneally injected with a solution of HSP60 at a dose of 4 mg/kg body weight, every other day for a total of three times at the 12th week. The learning and memory ability of mice was detected using the Morris water maze test. The enzyme-linked immunosorbent assay was used to detect the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in the hippocampal tissues of the mice. The relative expression of ionized calcium binding adaptor molecule-1 (IBA1) and TREM2 protein in the hippocampus of mice was detected using Western blot. Results i) The number of platform crossings of the mice in the hypertension group and the lead-exposed group was lower than that in the control group (both P<0.05). The escape latency of the mice on the third day was longer and the number of platform crossings was lower in the lead-exposed + hypertension group compared with the control group, hypertension group and lead-exposed group (all P<0.05). The levels of IL-1β, IL-6, and TNF-α in the hippocampus of the other three groups increased compared with the control group (all P<0.05). The relative expression of IBA1 protein in the hippocampus of lead-exposed group and lead-exposed + hypertension group increased (all P<0.05), while the relative protein expression of TREM2 decreased compared with the control group (all P<0.05). The levels of IL-1β, IL-6, TNF-α, and the relative protein expression of IBA1 protein in the hippocampus of the lead-exposed+hypertension group were higher (all P<0.05), and relative expression of TREM2 protein was lower (P<0.05) than those in the hypertension group. The level of TNF-α and the relative expression of IBA1 protein in the hippocampus of lead-exposed+hypertension group were higher than those in lead-exposed group (all P<0.05). ii) The escape latency of mice in the lead-exposed + hypertension group was longer than that in the control group (P<0.05), and the number of platform crossings was fewer than that in the control group (P<0.05). The escape latency of mice in the HSP60 intervention group was shortened (P<0.05), the number of platform crossings increased (P<0.05), and the levels of IL-1β, IL-6, TNF-α and relative expression of IBA1 protein decreased in the hippocampus (all P<0.05), while the relative expression of TREM2 protein increased (P<0.05) compared with the lead-exposed+hypertension group. Conclusion Combined exposure of lead and hypertension has a synergistic effect on learning and memory impairment in mice. The mechanism may be related to the inhibition of TREM2 expression by lead in the hippocampus of hypertensive mice and aggravating the neuroinflammatory response. Intervention with TREM2 receptor agonist HSP60 can alleviate learning and memory impairment in mice exposed to lead and hypertension by up-regulating TREM2 expression in the hippocampus.

miR-429-3p mediates memory decline by targeting MKP-1 to reduce surface GluA1-containing AMPA receptors in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a leading cause of dementia in the elderly. Mitogen-activated protein kinase phosphatase 1 (MKP-1) plays a neuroprotective role in AD. However, the molecular mechanisms underlying the effects of MKP-1 on AD have not been extensively studied. MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level, thereby repressing mRNA translation. Here, we reported that the microRNA-429-3p (miR-429-3p) was significantly increased in the brain of APP23/PS45 AD model mice and N2AAPP AD model cells. We further found that miR-429-3p could downregulate MKP-1 expression by directly binding to its 3'-untranslated region (3' UTR). Inhibition of miR-429-3p by its antagomir (A-miR-429) restored the expression of MKP-1 to a control level and consequently reduced the amyloidogenic processing of APP and Aβ accumulation. More importantly, intranasal administration of A-miR-429 successfully ameliorated the deficits of hippocampal CA1 long-term potentiation and spatial learning and memory in AD model mice by suppressing extracellular signal-regulated kinase (ERK1/2)-mediated GluA1 hyperphosphorylation at Ser831 site, thereby increasing the surface expression of GluA1-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs). Together, these results demonstrate that inhibiting miR-429-3p to upregulate MKP-1 effectively improves cognitive and synaptic functions in AD model mice, suggesting that miR-429/MKP-1 pathway may be a novel therapeutic target for AD treatment.

Electroacupuncture intervention on the proliferation and differentiation of hippocampal neurons and oligodendrocytes in Alzheimer's disease model mice / 中国组织工程研究

BACKGROUND:The effect of electroacupuncture on the proliferation and differentiation of hippocampal oligodendrocytes in model mice with Alzheimer's disease remains poorly understood while demyelinating reaction related to oligodendrocytes is a common pathological reaction of Alzheimer's disease. OBJECTIVE:To investigate the effects and mechanism of electroacupuncture stimulation of"Baihui"(GV 20),"Fengfu"(GV 16)and bilateral"Shenshu"(BL 23)in Alzheimer's disease model mice on the proliferation and differentiation of endogenous neural stem cells to neurons and oligodendrocytes. METHODS:Forty 6-week-old SPF APP/PS1 transgenic male Alzheimer's disease model mice were randomly divided into electroacupuncture group(n=20)and Alzheimer's disease model group(n=20).Healthy male C57BL/6J mice of the same age were used as normal controls(n=20).The mice in the electroacupuncture group received electroacupuncture at"Baihui"(GV 20),"Fengfu"(GV 16)and bilateral"Shenshu"(BL 23)for 16 weeks(20 minutes/day and one day off a week).After electroacupuncture,Morris water maze was used to detect the changes of learning and memory function.Immunohistochemistry was utilized to detect hippocampal dentate gyrus β-amyloid senile plaques.The expression of BrdU/NeuN and BrdU/GALC in the hippocampal dentate gyrus was detected by immunofluorescence double labeling.Western blot assay was used to detect the expression levels of neuron specific protein Nestin and oligodendrocyte specific protein GALC in the hippocampus.mRNA and protein levels of Notch1 and Hes1 in the hippocampus were detected by real-time fluorescence quantitative PCR and western blot assay. RESULTS AND CONCLUSION:(1)Compared with the normal control group,the ability of learning and memory in the Alzheimer's disease model group decreased significantly;hippocampal dentate gyrus β-amyloid senile plaques increased significantly(P<0.01);the expression of GALC and Nestin in the hippocampus decreased significantly(P<0.01,P<0.05).(2)Compared with the Alzheimer's disease model group,the learning and memory ability of the electroacupuncture group was significantly increased;β-amyloid senile plaque in the hippocampal dentate gyrus decreased significantly(P<0.01).BrdU/NeuN double labeled positive cells in the hippocampal dentate gyrus and Nestin protein expression in the hippocampus increased significantly(P<0.01,P<0.05);GALC expression in hippocampus increased significantly(P<0.01).The mRNA and protein levels of Notch1 in the hippocampus were significantly increased(P<0.05,P<0.01).The mRNA and protein levels of Hes1 in the hippocampus decreased significantly(P<0.05).(3)These findings indicate that electroacupuncture at"Baihui"(GV 20),"Fengfu"(GV 16)and bilateral"Shenshu"(BL 23)of the Alzheimer's disease model infant mice can promote the proliferation and differentiation of endogenous neural stem cells to neurons and oligodendrocytes,which may be regulated through the Notch1/Hes1 pathway.

Effects of aerobic exercise on adult hippocampal neurogenesis in Alzheimer's disease mice / 中国组织工程研究

BACKGROUND:Exercise improves Alzheimer's disease,dementia,and age-related cognitive abilities.A potential mediator between exercise and these health benefits may be adult hippocampal neurogenesis.Therefore,it is of great significance to explore whether and how exercise affects the adult hippocampal neurogenesis process in Alzheimer's disease mice. OBJECTIVE:To observe the effect of aerobic exercise on adult hippocampal neurogenesis of Alzheimer's disease mice,and to explore whether aerobic exercise can promote their adult hippocampal neurogenesis. METHODS:Three-month-old wild-type(C57BL/6Jnju)and APP/PS1 double transgenic Alzheimer's disease mice were randomly divided into four groups:wild control group,wild exercise group,Alzheimer's disease control group and Alzheimer's disease exercise group,with 20 mice in each group.The control group did not do exercise,and the exercise group did aerobic exercise for 5 months.After exercise intervention,real-time PCR,immunofluorescence and western blot assay were used to detect the expression levels of DCX,Ki67,βIII-tubulin and NeuN in the hippocampal tissue of mice in each group. RESULTS AND CONCLUSION:The expressions of DCX,βIII-tubulin and NeuN in the hippocampal dentate gyrus in the Alzheimer's disease control group were significantly lower than those in the wild control group(P<0.05).The expressions of DCX,Ki67,βIII-tubulin and NeuN were significantly higher in the hippocampal dentate gyrus in the Alzheimer's disease exercise group than those in the Alzheimer's disease control group(P<0.05).It is indicated that long-term aerobic exercise intervention can strengthen the proliferation,migration and differentiation of neurons during adult hippocampal neurogenesis and significantly increase the number of neuronal precursor cells and new neurons in Alzheimer's disease mice.

Effects of aerobic exercise on the expression of Notch1 and Caspase-3 in the hippocampus of Alzheimer's disease mice / 中国组织工程研究

BACKGROUND:β-amyloid protein and Tau protein have adverse effects on the cognitive function of Alzheimer's disease patients,and Notch1 and Caspase-3 can regulate the expression of β-amyloid protein and Tau protein.It is not clear whether Notch1 and Caspase-3 mediate the process of aerobic exercise to improve the cognitive ability of Alzheimer's disease patients.At present,there is a lack of studies on the effect of long-term aerobic exercise on the expression of Notch1 and Caspase-3 in the hippocampus of Alzheimer's disease mice. OBJECTIVE:To observe the expression of Notch1 and Caspase-3 in the hippocampus of Alzheimer's disease mice undergoing long-term aerobic exercise and to investigate the effects of Notch1 and Caspase-3 in Alzheimer's disease mice. METHODS:Wild type and APP/PS1 double-transgenic Alzheimer's disease mice aged 3 months were randomly divided into four groups:wild control group,wild exercise group,Alzheimer's disease control group and Alzheimer's disease exercise group,with 20 mice in each group.Mice in the control groups were not subjected to exercise,while those in the exercise groups received aerobic exercise intervention for 5 months.After the exercise intervention,Morris water maze was used to detect the spatial learning and memory ability of mice.Real-time PCR,immunofluorescence and western blot were used to detect the expressions of Aβ1-42,Tau,Notch1 and Caspase-3 in the hippocampal tissues of mice in each group. RESULTS AND CONCLUSION:The spatial learning and memory ability of Alzheimer's mice was significantly worse than that of wild-type mice(P＜0.05).The spatial learning and memory ability of mice in the exercise groups were significantly better than that in the corresponding control groups(P＜0.05).The expressions of Aβ1-42,Tau,Notch1 and Caspase-3 in the hippocampus were significantly higher in the Alzheimer's disease control group than the wild control group(P＜0.05)and were significantly lower in the Alzheimer's disease exercise group than the Alzheimer's disease control group(P＜0.05).To conclude,long-term aerobic exercise can improve the spatial learning and memory ability of Alzheimer's disease mice,which may be related to the decreased expression of Notch1,Caspase-3,Aβ1-42 and Tau protein in the hippocampus of Alzheimer's disease mice.

Research progress on the modulation mechanism of electroacupuncture for learning and memory impairment after ischemic stroke / 中国针灸

Electroacupuncture may play a role in treatment of learning and memory impairment after ischemic stroke by regulating phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA)/cAMP response element binding protein (CREB) signaling pathway, nerve growth factor (NGF)/tyrosine kinase-A (TrkA) signaling pathway, Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway, Notch signaling pathway, erythropoietin-producing hepatocyte (Eph)/ephrin signaling pathway. The interactions among these pathways should be further explored in treatment of learning and memory impairment after ischemic stroke.

Mechanism of Learning and Memory Impairment in Rats Exposed to Arsenic and/or Fluoride Based on Microbiome and Metabolome / 生物医学与环境科学（英文）

OBJECTIVE@#Arsenic (As) and fluoride (F) are two of the most common elements contaminating groundwater resources. A growing number of studies have found that As and F can cause neurotoxicity in infants and children, leading to cognitive, learning, and memory impairments. However, early biomarkers of learning and memory impairment induced by As and/or F remain unclear. In the present study, the mechanisms by which As and/or F cause learning memory impairment are explored at the multi-omics level (microbiome and metabolome).@*METHODS@#We stablished an SD rats model exposed to arsenic and/or fluoride from intrauterine to adult period.@*RESULTS@#Arsenic and/fluoride exposed groups showed reduced neurobehavioral performance and lesions in the hippocampal CA1 region. 16S rRNA gene sequencing revealed that As and/or F exposure significantly altered the composition and diversity of the gut microbiome，featuring the Lachnospiraceae_NK4A136_group, Ruminococcus_1, Prevotellaceae_NK3B31_group, [Eubacterium]_xylanophilum_group. Metabolome analysis showed that As and/or F-induced learning and memory impairment may be related to tryptophan, lipoic acid, glutamate, gamma-aminobutyric acidergic (GABAergic) synapse, and arachidonic acid (AA) metabolism. The gut microbiota, metabolites, and learning memory indicators were significantly correlated.@*CONCLUSION@#Learning memory impairment triggered by As and/or F exposure may be mediated by different gut microbes and their associated metabolites.

Contextual Fear Learning and Extinction in the Primary Visual Cortex of Mice / 神经科学通报·英文版

Fear memory contextualization is critical for selecting adaptive behavior to survive. Contextual fear conditioning (CFC) is a classical model for elucidating related underlying neuronal circuits. The primary visual cortex (V1) is the primary cortical region for contextual visual inputs, but its role in CFC is poorly understood. Here, our experiments demonstrated that bilateral inactivation of V1 in mice impaired CFC retrieval, and both CFC learning and extinction increased the turnover rate of axonal boutons in V1. The frequency of neuronal Ca2+ activity decreased after CFC learning, while CFC extinction reversed the decrease and raised it to the naïve level. Contrary to control mice, the frequency of neuronal Ca2+ activity increased after CFC learning in microglia-depleted mice and was maintained after CFC extinction, indicating that microglial depletion alters CFC learning and the frequency response pattern of extinction-induced Ca2+ activity. These findings reveal a critical role of microglia in neocortical information processing in V1, and suggest potential approaches for cellular-based manipulation of acquired fear memory.

The Memory Orchestra: Contribution of Astrocytes / 神经科学通报·英文版

For decades, memory research has centered on the role of neurons, which do not function in isolation. However, astrocytes play important roles in regulating neuronal recruitment and function at the local and network levels, forming the basis for information processing as well as memory formation and storage. In this review, we discuss the role of astrocytes in memory functions and their cellular underpinnings at multiple time points. We summarize important breakthroughs and controversies in the field as well as potential avenues to further illuminate the role of astrocytes in memory processes.

Effects of microwave radiation on learning and memory and neurotransmitters in the hippocampus / 中国辐射卫生

@#The central nervous system is one of the most sensitive targets of microwave radiation. Microwave radiation can affect spatial learning and memory and neural information transmission. The effects of microwave radiation on neurotransmitters in the hippocampus and the underlying mechanisms are still unclear. This paper reviews the effects of microwave radiation on learning/memory and neurotransmitters as well as the mechanisms of action on neurotransmitters. This paper aims to provide a scientific basis for future research in this area.