Effect of silibinin and trans-chalcone in an Alzheimer's disease-like model generated by insulin amyloids

Amyloid fibrils are characteristic of several disorders including Alzheimer's disease (AD), with no cure or preventive therapy. Diminishing amyloid deposits using aromatic compounds is an interesting approach toward AD treatment. The present study examined the anti-fibrillogenic effects of silibinin and trans-chalcone in vitro, in vivo, and in silico on insulin amyloids. In vitro incubation of insulin at 37°C for 24 h induced amyloid formation. Addition of trans-chalcone and silibinin to insulin led to reduced amounts of fibrils as shown by thioflavin S fluorescence and Congo red absorption spectroscopy, with a better effect observed for silibinin. In vivo bilateral injection of fibrils formed by incubation of insulin in the presence or absence of silibinin and trans-chalcone or insulin fibrils plus the compounds in rats' hippocampus was performed to obtain AD characteristics. Passive avoidance (PA) test showed that treatment with both compounds efficiently increased latency compared with the model group. Histological investigation of the hippocampus in the cornu ammonis (CA1) and dentate gyrus (DG) regions of the rat's brain stained with hematoxylin-eosin and thioflavin S showed an inhibitory effect on amyloid aggregation and markedly reduced amyloid plaques. In silico, a docking experiment on native and fibrillar forms of insulin provided an insight onto the possible binding site of the compounds. In conclusion, these small aromatic compounds are suggested to have a protective effect on AD.

Signos radiológicos en la neuroimagen de pacientes pediátricos con trastorno por estrés postraumático / Radiological signs in neuroimaging of pediatric patients with posttraumatic stress disorder

RESUMEN Introducción: El trastorno por estrés postraumático afectan la salud mental de los pacientes pediátricos, se considera muy común en estos pacientes. Estudios científicos apoyados en la resonancia magnética han fundamentado una estrecha relación entre el estrés postraumático y cambios estructurales en el cerebro. Se realizó una revisión bibliográfica en el periodo de abril a mayo de 2021, en los recursos disponibles en MEDLINE, SciELO, Pubmed y Elsevier. Del total de consultas se citaron 25 referencias. Objetivo: Describir los signos radiológicos en la neuroimagen de pacientes pediátricos con estrés postraumático. Desarrollo: Los estudios de neuroimagen en niños y adolescentes con trastorno por estrés postraumático se han centrado en estructuras anormales y la funcionalidad de algunas regiones individuales del cerebro; estas implican las regiones cerebrales asociadas con la fisiopatología, ellas son: la corteza prefrontal medial y dorsolateral; la corteza orbitofrontal; ínsula; núcleo lentiforme; amígdala; hipocampo y el parahipocampo; la corteza cingulada anterior y posterior; el precúneo; cúneo; el giro fusiforme y lingual y los tractos de materia blanca que conectan estas regiones cerebrales. Conclusiones: Los signos radiológicos en la neuroimagen de pacientes pediátricos con trastorno por estrés postraumático son: reducción de los volúmenes del hipocampo; del volumen cerebral e intracraneal y del volumen de la amígdala, así como una disminución del área total del cuerpo calloso. Además se observa que el volumen hipofisario y los volúmenes de materia gris cerebral fueron menores en los pacientes con estrés postraumático.

ABSTRACT Introduction: Post-traumatic stress disorder affects the mental health of pediatric patients; it is considered very common in these patients. Scientific studies supported by magnetic resonance imaging have established a close relationship between post-traumatic stress and structural changes in the brain. A bibliographic review was carried out in the period from April to May 2021, in the resources available in MEDLINE, SciELO, Pubmed and Elsevier. Of the total of consultations, 25 references were cited. Objective: To describe the radiological signs in the neuroimaging of pediatric patients with post-traumatic stress disorder. Development: Neuroimaging studies in children and adolescents with post-traumatic stress disorder have focused on abnormal structures and the functionality of some individual brain regions; these involve the brain regions associated with pathophysiology, they are: the medial and dorsolateral prefrontal cortex; the orbitofrontal cortex; insula; lentiform nucleus; amygdala; hippocampus and parahippocampus; the anterior and posterior cingulate cortex; the precuneus; cuneus; the fusiform and lingual gyrus and the white matter tracts that connect these brain regions. Conclusions: The radiological signs in the neuroimaging of pediatric patients with post-traumatic stress disorder are: reduction of the volumes of the hippocampus; brain and intracranial volume and amygdala volume, as well as a decrease in the total area of ​​the corpus callosum. In addition, it is observed that the pituitary volume and the volumes of cerebral gray matter were lower in patients with post-traumatic stress.

Activación de la microglía en el hipocampo asociada con lesión del nervio facial / Facial nerve injury-associated hippocampal microglíal activation

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.

Roles of c-Fos, EGR-1, PKA, and PKC in cognitive dysfunction in rats after propofol anesthesia

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

Effects of social isolation on cognitive function and phenotypic transition of hippocampal astrocytes in mice / 中华行为医学与脑科学杂志

Objective:To explore the effect of social isolation (SI) on cognitive function and the phenotypic transition of hippocampal astrocytes in mice.Methods:Twenty male C57BL/6 mice aged 3-4 weeks were randomly divided into normal group house (GH group) and social isolation group (SI Group). The mice in SI group were fed one per cage for 8 weeks to establish a social isolation model, and the mice in GH group were fed five per cage. The cognitive function of mice was detected by the novel object recognition test and novel location recognition test. The expression of astrocyte marker glial fibrillary acidic protein (GFAP) was detected by immunohistochemistry, RT-PCR and Western blot.The astrocyte morphology change was quantitatively analyzed by Sholl Analysis.The expression of the hippocampal A1-A2 astrocytes markers proteasome subunit beta 8(PSMB8) and a member of the S100 family of Ca 2+ -binding proteins (S100A10) were determined by RT-PCR and Western blot. Statistical analysis was performed using GraphPad Prism 6.0 software, and t-test was used for comparison between two groups. Results:The results of cognitive function showed that the exploration index of novel object ((-5.54±3.30)%, (33.42±7.14)%; t=4.680, P=0.001) and the exploration index of novel location((-7.96±4.81)%, (23.55±8.20)%; t=3.670, P=0.008) in SI group were both lower than those in GH group.Immunohistochemical results showed that the number of GFAP positive cells in hippocampus of SI group was significantly lower than that of GH group((369.90±42.97), (544.90±57.64); t=2.480, P=0.023). The results of Sholl analysis showed that the protuberance of hippocampal astrocytes in SI Group retracted.There were significant differences in the number of intersections between the two groups at 6, 8, 10, 12, 14 and 16 μm away from astrocyte cell body(all P<0.05). Western blot showed that the expression of GFAP protein in SI group was lower than that in GH group((0.85±0.05), (1.03±0.06); t=2.527, P=0.028). The results of PCR showed that the expression of GFAP mRNA in SI group was lower than that in GH group ((0.83±0.05), (1.00±0.03); t=2.970, P=0.018). The expression of A1 phenotypic marker PSMB8 mRNA ((1.58±0.17), (1.00±0.06); t=2.931, P=0.011) and A2 phenotypic marker S100A10 mRNA ((1.52±0.14), (1.00±0.07); t=3.121, P=0.007) in the hippocampus of SI group were higher than those in GH group.Compared with the GH group, the expression of the neurotrophic factors IGF-1 mRNA in the SI group was down-regulated ((0.73±0.07), (1.00±0.08); t=2.327, P<0.05), while the expression of LCN2 mRNA((1.12±0.03), (1.00±0.03), t=2.575, P<0.05), IL-1β mRNA(1.76±0.19), (1.00±0.07), t=3.460, P<0.01) and TNF-α mRNA((2.18±0.42), (1.00±0.07), t=2.427, P<0.05) were up-regulated in the SI group. Conclusion:The pathological mechanism of social isolation-induced cognitive impairment in mice may be related with the phenotypic changes of astrocytes.

Effect of Naozhenning on Hippocampal Mitochondrial Function in Model Rats with Post-concussion Syndrome / 中国实验方剂学杂志

ObjectiveTo explore the mechanism of Naozhenning on learning and memory ability and neuron damage in hippocampal CA1 region of post-concussion syndrome model rats based on mitochondrial function. MethodMultiple cerebral concussion （MCC） was induced in SPF Wistar rats with the free-fall impact method. Then the model rats were randomly classified into model group （equivalent volume of distilled water）， piracetam （0.43 g·kg-1， ig） group， and low-， medium-， and high-dose NZN （5.4， 10.8， 21.6 g·kg-1， respectively， ig） groups， with 10 rats in each group， and another 10 normal rats were included in the normal control group （equivalent volume of distilled water）. The administration lasted 14 days and then relevant indexes were detected. Morris water maze test was used to observe the changes of learning and memory ability in each group， such as escape latency， residence time in primary quadrant， and times of crossing platform. The pathological changes of hippocampal CA1 region were observed based on hematoxylin-eosin （HE） staining and Nissl staining. The ultrastructure of mitochondria was observed under the transmission electron microscope （TME） and the activity of mitochondrial respiratory chain complex Ⅰ was detected by colorimetry. The content of adenosine triphosphate （ATP） was determined by fluorescence probe and mitochondrial membrane potential （MMP） by fluorescein enzyme-linked fluorescence immunoassay. ResultCompared with the normal control group， the model group showed long escape latency， short residence time in target quadrant， few times of crossing the platform， significant decrease in counts of neurons and Nissl bodies in hippocampal CA1 region， damage of neuronal morphology and mitochondrial structure， and significant reduction of MMP and the content of mitochondrial ATP and respiratory chain complex I （P<0.05， P<0.01）. The NZN groups demonstrated short escape latency， long residence time in target quadrant， increased times of crossing the platform， small number of neurons and Nissl bodies in hippocampal CA1 region， alleviated damage of neuronal morphology and mitochondrial structure， and increase in MMP and the content of mitochondrial ATP and respiratory chain complex I （P<0.05， P<0.01）. ConclusionNZN can improve the learning and memory ability of MCC rats by improving mitochondrial structure and function and alleviating hippocampal neuron injury.

Comparative proteomic profiling of hippocampi in mice treated with Jingui Shenqi Pills and Liuwei Dihuang Pills / 中国中药杂志

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.

Dosimetric comparison of hippocampal avoidance wholebrain radiotherapy with flattening filter and flattening filter-free modes / 中国辐射卫生

@#<b>Objective</b> To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) with flattening filter(FF) and flattening filter-free(FFF) modes in hippocampal avoidance whole brain radiotherapy. <b>Methods</b> We included 15 patients with hippocampal-sparing whole brain radiotherapy, and designed two radiotherapy plans of FF-VMAT and FFF-VMAT for each patient. On the premise of meeting clinical dose requirements, the two plans’ dosimetry, total number of monitor units, and beam-on time were compared. <b>Results</b> There were no significant differences in the target coverage, conformity index, and dose gradient of the FF-VMAT and FFF-VMAT plans (<i>P</i> > 0.05). The <i>D</i>_max, <i>D</i>_100%, and <i>D</i>_meanto the hippocampal tissue were significantly lower with FFF-VMAT [(15.13 ± 0.38) Gy, (7.12 ± 0.34) Gy, and (9.76 ± 0.43) Gy, respectively)] than with FF-VMAT (16.46 ± 0.56) Gy, (7.72 ± 0.28) Gy, and (10.54 ± 0.48) Gy, respectively)] (<i>P</i> < 0.05). The <i>D</i>_maxto the left and right lenses and the <i>D</i>_meanto the left and right eyeballs with FFF-VMAT were (7.26 ± 0.43) Gy, (6.29 ± 1.13) Gy, (11.01 ± 0.94) Gy, and (9.78 ± 1.13) Gy, respectively, which were significantly lower than FF-VMAT’s corresponding doses of (8.09 ± 0.66) Gy, (7.80 ± 0.74) Gy, (11.38 ± 1.09) Gy, and (11.05 ± 0.90) Gy, respectively (<i>P</i> < 0.05). The doses to other organs at risk including the optic nerve and optic chiasm were all controlled within the safe dosage ranges, with no significant differences between the two plans (<i>P</i> > 0.05). The FFF-VMAT plan had a significantly greater number of monitor units and a significantly shorter beam-on time than the FF-VMAT plan (<i>P</i> < 0.05). <b>Conclusion</b> Both FF-VMAT and FFF-VMAT can meet the clinical requirements, with FFF-VMAT having better hippocampus and lens protection, shorter beam-on time, and higher treatment efficiency.

Effect of sciadopitysin on sodium arsenite-induced senescence of rat hippocampal neurons / 环境与职业医学

Background In addition to the typical signs of skin damage, long-term arsenic exposure is often accompanied by signs and symptoms of neurobehavioral abnormalities. Objective To investigate potential intervention effect of sciadopitysin on senescence of neurons induced by sodium arsenite in rats and possible underlying mediating effect of cell cycle-related transcription factor E2F1. Methods SH-SY5Y cells were treated with 4 μmol·L−1 sodium arsenite for 24 h and intervened with 50 μg·mL−1 Ginkgo biloba extract (EGb761) or four major biflavonoids in Ginkgo biloba leaves (isoginkgetin, bilobetin, sciadopitysin, and ginkgetin) for 24 h respectively. Then, cell viability was measured by CCK-8 assay. Thirty-two 180-200 g SPF rats were randomly divided into a control group, an arsenic treatment group (10 mg·L−1), a Ginkgo biloba extract intervention group (10 mg·kg−1), and a sciadopitysin intervention group (10 mg·kg−1), 8 rats in each group, half male and half female. The rats were treated with sodium arsenite by free drinking water for 3 consecutive months, and the intervention treatment was conducted after 2 months of poisoning with drug intake by gavage for 1 month. HE staining was used to detect structural changes in the hippocampus, while Nissl's staining was used to detect changes in hippocampal morphology and neuron numbers. Moreover, senescence-associated β galactosidase (SA-β-gal) staining and Western blotting were used to detect senescence of hippocampal neurons and the expression level of E2F1, respectively. Results Compared to the arsenic treatment group, EGb761 and the four biflavonoids in Ginkgo biloba leaves effectively antagonized the inhibitory effect of sodium arsenite on cell viability (all Ps＜0.05), and sciadopitysin showed better restoration of cellular viability than Ginkgo biloba extract (P＜0.05). The results of HE staining and Nissl's staining showed that the hippocampal neurons in the arsenic treatment group were reduced in cell count and the synaptic structure was abnormal, with swelling, nuclear shrinkage, and vacuole, compared with the control group. The results of SA-β-gal staining showed that the number of senescent cells in the arsenic treatment group (15.75±3.01) was significantly increased compared with the control group (2.88±0.84) (P＜0.05); the numbers of senescent cells in the Ginkgo biloba extract group (9.38±1.92) and the sciadopitysin treatment group (7.75±2.38) were significantly decreased compared with the arsenic treatment group (all Ps＜0.05). The results of Western blotting showed that compared with the control group, the expression of E2F1 protein in hippocampus of the arsenic treatment group was significantly decreased (1.00±0.17 vs. 0.65±0.19, P<0.05); compared with the arsenic treatment group, the protein expression level of E2F1 in hippocampus of the sciadopitysin treatment group (0.89±0.18) was significantly recovered (P<0.05); compared with Ginkgo biloba extract (0.68±0.19), sciadopitysin had a better recovery effect on E2F1 expression level (0.89±0.18) (P＜0.05). The results of correlation analysis showed that the E2F1 protein expression level was negatively correlated with the positive rate of SA-β-gal staining in hippocampal neurons (r=−0.518, P＜0.05). Conclusion Sciadopitysin is an effective component of Ginkgo biloba extract. It can effectively inhibit the senescence of hippocampal neurons induced by sodium arsenite, and E2F1 may play an important mediating role.

Effects of acupuncture plus medication on hippocampus SIRT1 and FOXO3a expression, MDA content, and SOD activity of rats with Alzheimer disease / 针灸推拿医学（英文版）

Objective: To observe the effect of the acupuncture plus medication on the expression of silent information regulator of transcription 1 (SIRT1) and transcription factor forkhead box protein O3a (FOXO3a) in the hippocampus, the malondialdehyde (MDA) content, and the superoxide dismutase (SOD) activity of rats with Alzheimer disease (AD), and to explore the possible mechanism of combining acupuncture and medication in improving AD-related neurological symptoms. Methods: Sixty male Sprague-Dawley rats were divided into a normal group, a model group, an electroacupuncture (EA) group, a drug group, and an acupuncture-medication combined group by the random number table method, with 12 rats in each group. The model was established by micro-injection of streptozotocin into the bilateral lateral ventricles. After successful modeling, rats in the EA group received EA at Zusanli (ST36) and Dazhui (GV14), those in the drug group received intragastric administration of resveratrol at a dose of 44 mg/(kg·bw), and those in the acupuncture- medication combined group received the combined intervention of EA and resveratrol. Rats in each group received intervention once a day for 4 consecutive weeks. Morris water maze was used to detect the rat behavioral changes. Nissl staining method was used to observe the cell morphology and changes in the number of rat hippocampal neurons. Western blotting and immunohistochemical staining methods were used to observe the expression changes of SIRT1 and FOXO3a. The thiobarbituric acid method was used to detect the MDA content. SOD activity was determined by the hydroxylamine method. Results: Compared with the normal group, the escape latency was significantly prolonged (P<0.05); the percentage of stay in the target quadrant was reduced (P<0.05), the hippocampal neuronal cells were shrunken, nucleoli were unclear, and cell number was reduced (P<0.05); the SIRT1 expression and SIRT1 positive cell number were decreased, while the FOXO3a expression and FOXO3a positive cell number were increased significantly (P<0.05); the MDA content was increased significantly, and the SOD activity was decreased significantly (P<0.05) in the model group. Compared with the model group, the escape latency was shortened (P<0.05); the percentage of stay in the target quadrant was increased (P<0.05); the shape and number of hippocampal neurons tended to be normal (P<0.05); the SIRT1 protein expression and the SIRT1 positive cell numbers were increased, the FOXO3a protein expression and the FOXO3a positive cell number were decreased (P<0.05); the MDA content was significantly decreased, and the SOD activity was significantly increased (P<0.05) in the EA group, the drug group, and the acupuncture-medication combined group. The changes in the acupuncture-medication combined group were more obvious (P<0.05). Conclusion: Both EA and resveratrol improve the learning and memory ability of AD rats by regulating the expression of SIRT1 and FOXO3a and improving the levels of MDA and SOD in the hippocampus and protect the hippocampal neurons, while the combined use of EA and medication is more effective than EA or resveratrol alone, suggesting that this combined treatment is more effective in AD treatment.

Effects of 60Co γ-rays on brain injury and polarization of microglia/macrophages in mice / 中华微生物学和免疫学杂志

Objective:To analyze the damage in hippocampal tissues of mice after whole-body irradiation with high- or low-dose ionizing radiation and to investigate the roles of microglia/macrophages polarization in the injury.Methods:C57BL/6 mice were randomly divided into three groups: sham irradiation group, low-dose group (0.05 Gy) and high-dose group (7 Gy). Low- and high-dose groups were respectively treated by whole-body irradiation with single dose of 60Co γ-rays. Hippocampal tissues of the mice were collected at 6 h, 1 d, 3 d and 7 d after irradiation. The morphology, structure and apoptosis of neurons were detected by HE staining, Nissl staining and Tunnel staining, respectively. RT-PCR and immunofluorescence assay were performed to detect the expression of M1 and M2 microglial markers at mRNA and protein levels in hippocampus tissues. The cognitive and emotional behaviors of mice were evaluated one month after the irradiation by Morris water maze, open field test, elevated plus maze and tail suspension test. Results:There were morphological and structural changes in the nerve cells in the hippocampus region of mice after irradiation, accompanied by apoptosis. Acute injuries occurred at 6 h after radiation, alleviated at 1 d and 3 d, and persisted at 7 d in a dose-dependent manner. The results of immunofluorescence staining and confocal imaging analysis showed that compared with the sham irradiation group, the high-dose group showed increased number of microglia, down-regulated expression of M1 microglial markers and up-regulated expression of M2 microglial markers in the hippocampus at 6 h and 1 d after radiation, while M2 microglial markers decreased at 3 d and 7 d after irradiation. PCR results showed that the expression of M1 and M2 microglial markers at mRNA level in the irradiation groups increased at 6 h after irradiation, but there was no statistical significance. The expression of related proinflammatory/anti-inflammatory factors was significantly up-regulated. The results of behavioral experiments showed that compared with the sham irradiation group, there was no statistical difference in cognitive or emotional behaviors at one month after irradiation.Conclusions:60Co γ-rays could damage mouse hippocampal tissues and result in the overexpression and different polarization patterns of microglia/macrophages in mice.

Role of hippocampal REV-ERBα in postoperative cognitive dysfunction in rats / 中华麻醉学杂志

Objective:To evaluate the role of hippocampal REV-ERBα in postoperative cognitive dysfunction in rats.Methods:Thirty-two SPF healthy male Sprague-Dawley rats, aged 12-14 weeks, weighing 360-380 g, were divided into 4 groups ( n=8 each) using a random number table method: control group (group C), surgery group (group S), surgery + dimethyl sulfoxide (DMSO) group (group SD), and surgery + SR9009 group (group SS). Exploratory laparotomy was performed under sevoflurane anesthesia in S, SD and SS groups.Normal saline containing 0.1% DMSO was injected into hippocampal CA1 area at 1 h before laparotomy, with 2 μl on each side in group SD, and REV-ERBα agonist SR9009 (in normal saline containing 0.1% DMSO) was injected into hippocampal CA1 area at 1 h before laparotomy, with 2 μl on each side in group S+ SR9009.Morris water maze test was performed at 1 and 3 days after operation.Rats were sacrificed at 1 h after the end of Morris water maze test on day 3 after surgery, and the hippocampal tissues were obtained for determination of the expression of REV-ERBα, Brain and Muscle ARNT-Like 1 (BMAL1) protein, synaptophysin (SYN), postsynaptic density (PSD)-95 protein and N-methyl-D-aspartate receptor 2B subunit (GRIN2B) (by Western blot) and microscopic examination of the morphology of hippocampal neurons and Nissl bodies (by Nissl staining), and the viable neurons were counted. Results:Compared with group C, the percentage of time of staying at the target quadrant was significantly decreased, and the number of crossing platform was reduced on days 1 and 3 after exploratory laparotomy, the expression of REV-ERBα, BMAL1, PSD95, SYN and GRIN2B was down-regulated, and the number of viable neurons was decreased in group S and group SD ( P<0.05). Compared with group S and group SD, the percentage of time of staying at the target quadrant and the number of crossing platform were significantly increased on days 1 and 3 after exploratory laparotomy, the expression of REV-ERBα and PSD95 was up-regulated, the number of viable neurons was increased ( P<0.05), and no significant change was found in the expression of BMAL1, SYN and GRIN2B in group SS ( P>0.05). There was no significant difference in the indexes mentioned above between group S and group SD ( P>0.05). Conclusions:Activation of REV-ERBα can improve postoperative cognitive dysfunction, and the mechanism may be related to up-regulation of PSD95 expression in hippocampus and reduction of neuronal damage in rats.

Role of Shh/Gli1 signaling pathway in sleep deprivation-induced cognitive impairment in young mice / 中华麻醉学杂志

Objective:To evaluate the role of sonic hedgehog (Shh)/glioma-associated oncogene homolog 1 (Gli1) signaling pathway in sleep deprivation-induced cognitive impairment in young mice.Methods:Forty-eight SPF healthy male C57BL/6 mice, aged 4 weeks, weighing 14-16 g, were divided into 3 groups ( n=16 each) by the random number table method: control group (C group), sleep deprivation group (SD group) and Shh agonist SAG group (SD+ SAG group). Multi-platform water environment method was used to prepare the sleep deprivation model in mice, and the sleep deprivation was 20 h a day for 10 consecutive days.In SD+ SAG group, SAG 10 mg/kg was intraperitoneally injected at 5 min before each sleep deprivation, while the equal volume of normal saline was intraperitoneally injected in group C and group SD.The mice underwent novel object recognition and Y-maze tests at 24 h after development of the model.Mice were sacrificed after the behavioral testing, and the hippocampi were isolated for determination of the density of dendritic spines in hippocampal CA1 region (by Golgi staining), expression of Gli1 and brain-derived neurotrophic factor (BDNF) in hippocampal tissues (by Western blot), and expression of Gli1 and BDNF mRNA in hippocampal tissues (by quantitative real-time polymerase chain reaction). Results:Compared with group C, the preference index in novel object recognition and Y-maze tests and density of dendritic spines in CA1 region were significantly decreased, and the expression of Gli1 and BDNF protein and mRNA in hippocampus was down-regulated in group SD ( P<0.05). Compared with group SD, the preference index in novel object recognition and Y-maze tests and density of dendritic spines in CA1 region were significantly increased, and the expression of Gli1 and BDNF protein and mRNA in hippocampus was up-regulated in group SD+ SAG ( P<0.05). Conclusions:Inhibition of Shh/Gli1 signaling pathway and reduction of plasticity of dendritic spines of hippocampal neurons are involved in sleep deprivation-induced cognitive impairment in young mice.

Effect of dexmedetomidine pretreatment on autophagy of hippocampal neurons in developing rats under sevoflurane anesthesia / 中华麻醉学杂志

Objective:To evaluate the effect of dexmedetomidine pretreatment on the autophagy of hippocampal neurons in the developing rats under sevoflurane anesthesia.Methods:Thirty-six clean-grade healthy Sprague-Dawley rats of either sex, aged 7 days, weighing 12-15 g, were divided into 3 groups ( n=12 each) using a random number table method: control group (group C), sevoflurane group (group S), and sevoflurane plus dexmedetomidine group (group S+ D). On 7-9 days after birth, and the animals were exposed to 3% sevoflurane (oxygen concentration inhaled 29%, oxygen flow 2 L/min, 2 h/day) after intraperitoneal injection of 25 μg/kg dexmedetomidine every day in group S+ D, the animals were exposed to sevoflurane after intraperitoneal injection of the equal volume of normal saline in group S, and the animals were exposed to gas mixture after intraperitoneal injection of the equal volume of normal saline in group C. The Morris water maze test was carried out at 20 days after birth, and the place navigation test and spatial probe test were performed.After the end of Morris water maze test, the anesthetized rats were sacrificed, and the hippocampus was obtained for determination of the expression of microtubule-associated protein light chain 3(LC3), BECN1 and P62 by Western blot. Results:Compared with group C, the escape latency was significantly prolonged, the frequency of crossing the original platform was decreased, the expression of LC3 and BECN1 was up-regulated, and the expression of P62 was down-regulated in group S and group S+ D ( P<0.05). Compared with group S, the escape latency was significantly shortened, the frequency of crossing the original platform was increased, the expression of LC3 and BECN1 was down-regulated, and the expression of P62 was up-regulated in group S+ D ( P<0.05). Conclusions:The mechanism by which dexmedetomidine pretreatment improves sevoflurane-induced cognitive dysfunction is related to reduction of excessive autophagy in hippocampal neurons of developing rats.

Chronic intermittent hypobaric hypoxia improved the memory and cognitive impairment of mice with whole brain irradiation / 中华放射医学与防护杂志

Objective:To observe the changes in hippocampus (CA1) and study the effect of chronic intermittent hypobaric hypoxia (CIHH) preconditioning on the memory and cognitive function of mice exposed to the whole brain irradiation.Methods:A total of 48 C57BL/6 male mice were randomly divided into control group, CIHH group, irradiation group (IR group) and CIHH+ IR group. For IR group, the whole brain of mice were irradiated with 10 Gy of 6 MV X-rays in a single fraction. Pretreatment with CIHH was performed by placing mice in a hypobaric chamber before radiation. The mirrors water maze experiment was performed in the four groups to observe the escape latency, the number of crossing platforms and the target quadrant residence time. Nissl staining was used to observe the changes of neuronal cells in hippocampal CA1 region. Immunofluorescence was used to detect the expression of microtubule-associated protein cells (DCX) in the subgranular zone (SGZ) of hippocampal dentate gyrus (DG) to evaluate neurogenesis.Results:After 30 days of whole brain irradiation, the escape latency of mice prolonged gradually, the frequency of crossing platform decreased ( P< 0.001), and the exploration time in the target quadrant decreased ( P<0.001). X-ray irradiation caused disorder of mice neuronal cells, degeneration and necrosis of neuronal cells, and decrease of DCX expression in CA1 region of mice. Compared with IR group, the CIHH+ IR group had shortened the escape latency, increased the frequency of crossing platform [(2.08±0.26) vs. (0.83±0.24), P<0.001], and also increased the exploration time in the target quadrant [(14.12±0.82)s vs. (7.42±0.73)s, P<0.001]. Pretreatment with CIHH also alleviated the deformation and necrosis of neurons in hippocampus, and increased DCX expression in CA1 region. Conclusions:Pretreatment of mice with CIHH plays a protective role in radiation induced hippocampal injury.

Influence of microwave radiation on associative learning and memory function and hippocampal structure in mice / 中华放射医学与防护杂志

Objective:To investigate the effects of microwave radiation on associative learning and memory function and hippocampal structure of mice.Methods:C57BL/6N mice were ramdomly divided into sham-radiated group ( n=27) and radiation group ( n=2). The radiation group was exposed to microwave at 2.856 GHz, 8 mW/cm 2 for 15 min, then their spatial and associative learning and memory function were examined with the morris water maze and shuttle box behavior experiment. The pathological changes of hippocampal tissue were observed by HE staining and light microscope, the ultrastructural changes of hippocampal tissue were observed by transmission electron microscope. Results:After microwave radiation, the times of mice crossing the platform for the reverse space exploration decreased from(3.60±0.79) times to (2.55±0.47) times( t=2.21, P=0.046), the average active escape rate decreased significantly ( t = 2.70, P<0.05), and the average active latency and the total shock time was significantly prolonged ( t = -3.09, -3.02, P < 0.05). At 8 d after microwave radiation, the nuclei of some neurons in the CA3 and DG regions of the hippocampus were pyknosis. The neurons were apoptotic, the synaptic spaces blurred, the glial cells swollen, and the perivascular spaces widened in the CA3 region of the hippocampus. Conclusions:Microwave radiation can decline the spatial reference memory ability and associative learning and memory ability of mice. The morphological and pathological changes of hippocampus are the structural basis of this dysfunction.

Effect of long-term intake of ω-3 polyunsaturated fatty acids on activation of hippocampal microglia in a mouse model of POCD / 中华麻醉学杂志

Objective:To evaluate the effect of long-term intake of ω-3 polyunsaturated fatty acids (ω-3 PUFAs) on the activation of hippocampal microglia in a mouse model of postoperative cognitive dysfunction (POCD).Methods:Ninety-six clean-grade healthy male C57BL/6 mice, aged 8 weeks, weighing 18-24 g, were stratified according to body weight and divided into 4 groups ( n=24 each) by a random number table method: control diet group (group C), ω-3 PUFAs group (group ω), control diet plus POCD group (group C+ P) and ω-3 PUFAs plus POCD group (group ω+ P). Mice were fed a special ω-3 PUFAs diet (DHA 0.14 g/100 g, EPA 0.03 g/100 g) for 12 weeks in group ω and group ω+ P, while mice were fed with a control diet for 12 weeks in group C and group C+ P.Tibial fracture procedures were performed under isoflurane anesthesia to develop the POCD model after 12 weeks of feeding.The fear conditioning test and Y maze test were performed on 1st and 3rd days after developing the model.The mice were sacrificed after behavioral tests, and the hippocampal tissues were removed for determination of the contents of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) (by gas chromatography-mass spectroscopy), density of Iba-1 positive microglia (by immunofluorescence staining), and expression of mature brain-derived neurotrophic factor (mBDNF) and precursor brain-derived neurotrophic factor (pro-BDNF) (by Western blot), and contents of interleukin-1beta (IL-1β) and interleukin-6 (IL-6) (by enzyme-linked immunosorbent assay). Results:Compared with group C, the contents of DHA and EPA were significantly increased, the percentage of freezing time in the contextual test was increased, mBDNF/pro-BDNF ratio was increased ( P<0.05), no significant change was found in the rotation accuracy in Y maze test, density of Iba-1 positive microglia and contents of IL-1β and IL-6 in hippocampus ( P>0.05) in group ω ( P<0.05), and no significant change was found in the contents of DHA and EPA ( P>0.05), the percentage of freezing time in the contextual test and accuracy of rotation in Y maze test were decreased on 1st and 3rd days after operation, the density of Iba-1 positive microglia and contents of IL-1β and IL-6 were increased, and mBDNF/pro-BDNF ratio was decreased in group C+ P ( P<0.05). Compared with group C+ P, the contents of DHA and EPA were significantly increased, the percentage of freezing time in the contextual test and accuracy of rotation in Y maze test were increased on 1st and 3rd days after operation, the density of Iba-1 positive microglia and contents of IL-1β and IL-6 were decreased, and mBDNF/pro-BDNF ratio was increased in group ω+ P ( P<0.05). Conclusions:Long-term intake of ω-3 PUFAs can improve cognitive function in a mouse model of POCD, and the mechanism may be related to inhibition of activation of hippocampal microglia, reduction of inflammatory responses, and thus increasing the mBDNF/Pro-BDNF ratio.

Effect of histone deacetylase inhibitor on neuropathic pain and pain-induced memory impairment in mice / 中华行为医学与脑科学杂志

Objective:To investigate the effect and mechanism of non-selective histone deacetylase (HDAC) inhibitor sodium butyrate (NaB) on neuropathic pain and pain-induced memory impairment in mice.Methods:Forty clean grade male C57BL/6J mice were were divided into 4 groups by random number table method ( n=10 in each group): sham + saline, sham + NaB, chronic constriction injury (CCI)+ saline and CCI + NaB.The mouse CCI model was established by sciatic nerve ligation. Non-selective HDAC inhibitors NaB(300 mg/kg) was intraperitoneally injected into the mice in Sham+ NaB group and CCI+ NaB group once a day 15-28 days after modeling, while the mice in Sham+ saline group and CCI+ saline group were intraperitoneally injected with the same volume of saline. On the 14th and 28th day after operation, the athletic ability was measured by open field test (OFT), the pain behavior was measured by paw withdrawal threshold (PWT) and paw withdrawal latency (PWL), and the memory function was measured by Y-maze. After the behavioral experiment, hippocampus and spinal dorsal horn tissues were taken for the activity of HDAC measurement, and hippocampus tissues were taken for the expression levels of BDNF and PSD95 measurement. SPSS 25.0 software was used for statistical analysis. The data were compared by repeated measurement ANOVA and one-way ANOVA. Results:After treatment with NaB, the interaction effects of the accuracy of spontaneous alternation of PWT, PWL and Y maze in mice were significant( F=21.07, 6.98, 7.79, all P<0.05). Compared with the Sham + saline group, the PWT((0.83±0.30)g, (0.25±0.22)g, (0.24±0.11)g; both P<0.05), the PWL((14.97±4.02)s, (5.99±1.51)s, (6.87±0.90)s; both P<0.05) and the spontaneous alternation in Y maze(71.57±2.80)%, (56.96±0.60)%, (62.86±4.94)%; both P<0.05) in CCI+ Saline group and CCI+ NaB group were lower. After treatment with NaB, compared with CCI + saline group, PWT((0.22±0.13)g, (0.62±0.23)g; P<0.05), PWL((5.62±2.00)s, (8.82±2.13)s; P<0.05)and the accuracy of spontaneous alternation of Y maze were significantly higher ((56.54±7.50)%, (66.35±8.20)%; P<0.05), the HDAC activity in hippocampus((173.40±7.38)%, (122.70±8.40)%; P<0.05)and in spinal cord ((153.40±10.58)%, (111.40±11.40)%; P<0.05)were significantly lower, and the expression of BDNF((0.65±0.06), (0.87±0.43); P<0.05)and PSD95((0.70±0.40), (0.87±0.04); P<0.05)were significantly higher in CCI + NaB group. Conclusion:NaB can improve neuropathic pain and pain-induced memory impairment.The mechanism may be related to the inhibition of HDAC activity and the up-regulation of BDNF and PSD95 expression in hippocampus.

Effects of early sleep deprivation on depressive-like behavior and hippocampus synaptic plasticity in adult depression model mice / 中华行为医学与脑科学杂志

Objective:To investigate the effects of early sleep deprivation(SD) on depressive-like behavior and hippocampus synaptic plasticity in adult mice with chronic unpredictable mild stress(CUMS) model.Methods:Thirty 2-week-old clean grade male mice were randomly divided into control group (CON group), CUMS group and SD + CUMS group according to the random number table, with 10 mice in each group. The mice in SD + CUMS group were subjected with sleep deprivation for 4 hours once a day during puberty (3 ~ 6 weeks old), and then were stimulated by CUMS after adulthood (9 weeks old). The mice in CUMS group were subjected with CUMS at the age of 9 weeks. And the mice in CON group were not given any intervention.The depressive-like behavior was evaluated by body weight, sugar water preference, tail suspension test and forced swimming test.The density of dendritic spines of basal and apical neurons in hippocampal CA1 was measured by Golgi staining, the frequency and amplitude of miniature excitatory postsynaptic current(mEPSC) of pyramidal neurons in the hippocampal CA1 region of mice were measured by electro-physiological patch clamp technique.Graphpad prism 7.0 software was used for statistical analysis and mapping. One-way ANOVA was used for comparison among multiple groups, and Tukey test was used for further pairwise comparison.Results:(1) After stress modeling, there were significant differences in body weight, sugar water preference percentage, forced swimming immobility time and tail suspension time among the three groups ( F=71.63, 39.82, 44.13, 43.07, all P<0.01). Compared with CON group, the mice in CUMS group and SD+ CUMS group had lower body weight ((25.51±0.37) g, (22.92±0.31) g, (20.12±0.27) g, both P<0.01), lower sugar water percentage preference ((87.40±1.65) %, (63.42±3.33) %, (49.68±3.70)%, both P<0.01), longer immobile time of forced swimming ((34.30±5.32) s, (119.20±12.03) s, (153.80±9.17) s, both P<0.01) and longer immobile time of tail suspension test((115.20±8.19)s, (156.80±4.35) s, (192.00±4.12) s, both P<0.01). Compared with CUMS group, SD+ CUMS group had lower body weight ( P<0.01), lower sugar water preference percentage ( P<0.05), longer immobile time in forced swimming test( P<0.05) and longer immobile time in tail suspension test( P<0.01). (2) Golgi staining results showed that the densities of dendritic spines of apical neurons and basal neurons in hippocampal CA1 area of the three groups were significantly different ( F=38.41, 41.34, both P<0.01). The densities of dendritic spines of basal and apical hippocampal neurons in CUMS group and SD+ CUMS group were lower than those in CON group ((7.74±0.22)/10 μm, (6.58±0.27)/10 μm, (5.00±0.13)/10 μm, both P<0.01), ((8.90±0.23)/10 μm, (7.63±0.30)/10 μm, (6.01±0.14)/10 μm, both P<0.01). Compared with CUMS group, the mice in SD+ CUMS group had lower densities of dendritic spines of basal and apical hippocampal neurons(both P<0.01). (3) Electrophysiological results showed that there were significant differences in the frequency and amplitude of mEPSC in hippocampal pyramidal neurons of the three groups ( F=38.90, 63.37, both P<0.01). Compared with CON group, the frequency and amplitude of mEPSC in pyramidal neurons of CA1 in CUMS group and SD+ CUMS group were significantly lower ((0.39±0.03)Hz, (0.20±0.02)Hz, (0.07±0.02)Hz, both P<0.01; (9.98±0.31)pA, (7.74±0.21)pA, 6.36±0.13)pA, both P<0.01). Compared with CUMS group, the frequency and amplitude of mEPSC in SD+ CUMS group were lower (both P<0.01). Conclusion:Adolescent sleep deprivation aggravates depressive behavior and hippocampus synaptic plasticity impairment in adult CUMS model mice.

Effects of foraging exercise on depressive-like behaviors and expression of transforming growth factor-β1 in hippocampus of rats with ischemic stroke after chronic stress / 中华行为医学与脑科学杂志

Objective:To explore the effects of foraging exercise (FE) on depressive-like behaviors and expression of transforming growth factor-β1 (TGF-β1) in hippocampus of rats with ischemic stroke after chronic stress.Methods:The right middle cerebral artery occlusion (MCAO) model was used in 30 male adult clean grade SD rats by suture method.According to the body weight, rats were evenly divided into stroke group ( n=10) and chronic unpredictable mild stimulation (CUMS) group ( n=20). Rats of CUMS group received stress induction 1 week after operation and lasted for 3 weeks. Then, according to random number generator of SPSS 24.0 software, the depression rats were divided into post-stroke depression (PSD) group( n=10) and FE groups ( n=10). The FE group received free FE intervention for 4 weeks. Body weight, water maze test, novelty inhibition feeding test (NSFT) and sucrose preference test (SPT) were performed at the end of the 1st, 4th and 8th week, respectively. The expression of TGF-β1 in hippocampus was detected by Immunohistochemistry (IHC) and Western blot (WB), and the levels of TGF-β1 and TNF-α in serum were detected by ELISA. SPSS 24.0 software was used for statistical analysis. The behavioral data were compared by two factor repeated measurement analysis of variance. One way ANOVA was used for comparison among groups, and LSD test was used for further pairwise comparison. Results:(1) The interaction between group and time had statistical significance on body weight, latency and food intake of NSFT and sucrose preference index(SPI) ( F=2.936-12.098, all P<0.05). After 4 weeks, compared with the stroke group((343.80±19.34)g, (12.10±6.97)s, (0.75±0.09)%), the body weight((307.80±17.23)g, (305.30±24.39)g), and SPI((0.52±0.06)%, (0.53±0.07)%) of PSD group and FE group were lower and the NSFT latency((21.70±7.02)s, (22.40±0.84)s) was longer (all P<0.05). After 8 weeks, SPI in FE group was higher than that in PSD group ( P=0.045). There were significant differences in body weight of three groups, NSFT latency and SPI of PSD group and FE group, and food intake of stroke and FE group ( F=8.478-196.548, all P<0.05). There was no interaction between group and time in the water maze test. Main effect of time ( P=0.034) and main effect of group ( P<0.01) had statistical significance on escape latency. The escape latency after 4 weeks was longer than that after 1 week ( P=0.003). The latency of PSD group was longer than that of stroke group ( P=0.005), and latency of FE group was shorter than that of the PSD group ( P<0.01). The main effect of group had statistical significance in the number of crossing quadrant ( P<0.01). The number of crossing quadrant of FE group was less than that of PSD group ( P<0.01). (2) Immunohistoche mistry staining showed that compared with the stroke group, the expression of TGF-β1 was down-regulated in 3 areas of hippocampus of PSD group (CA1, CA3 and DG) ( t=5.449-9.353, all P<0.01). Compared with stroke group, the expression of TGF-β1 of CA1 ( t=7.433, P<0.01) in FE group was down-regulated, but was up-regulated in CA3 ( t=3.342, P<0.05) of FE group. Compared with the PSD group, the expression of TGF-β1 was up-regulated in CA3 and DG of FE group ( t=7.811, 8.790, both P<0.01). (3) Western blot results: Compared with stroke group, the expression of TGF-β1 in hippocampus of PSD group was down-regulated ( t=3.255, P<0.01). Compared with the PSD group, the expression of TGF-β1 in hippocampus of FE group was up-regulated ( t=2.906, P<0.05). (4) ELISA detection showed that compared with the stroke group, the levels of TGF-β1 decreased ( t=2.224, P<0.05), but TNF-α increased ( t=6.127, P<0.01) in PSD group.Compared with the PSD group, the expression of TGF-β1 in FE group increased significantly ( t=4.417, P<0.01). Conclusion:Foraging exercise can improve the depressive behavior symptoms of ischemic stroke rats after chronic stress, and its mechanism may be related to the increasing expression of TGF-β1, which can alleviate the inflammatory reaction in hippocampus.