Ultrastructural Changes In Neurons Research Articles

Response of multipolar retinal neurons to photodamage in the experiment

Purpose: to assess the reaction of multipolar retinal neurons to light irradiation depending on the intensity and duration of exposure. Material and methods. Outbred sexually mature white rats (n = 50, 100 eyes) weighing 180–200 g were exposed to continuous round-the-clock light (200, 3,500 lux; 1, 2, 7, 14, 30 days). The control group consisted of 25 non-irradiated animals (50 eyes). Using semifine sections, colored with toluidine blue, we counted the number of neurons in the ganglionic layer with karyopyknosis, focal and total chromatolysis. In the optic nerve, the percentage of degeneratively altered axons and the number of nerve fibers with deformation of the myelin sheath were calculated. Ultrastructural changes in neurons were studied using a JEM-100 CX-II electron microscope. Results. In the first days of the experiment (1, 2 days), reactive and destructive changes in organelles are observed in the perikaryons of multipolar retinal neurons. The granular endoplasmic reticulum becomes fragmented, loses part of its ribosomes, and vacuoles of varied sizes are formed from its cisterns. With an increase in the duration of exposure (7–30 days), degradation processes are increasing, all the more so after high-intensity (3,500 lux) light irradiation. The photodamage causes changes in all components of the optic nerve and is characterized by a destruction of organelles, a decrease in the number of elements of the cytoskeleton in the axon, and myelin sheath splitting. Conclusion. Changes in multipolar neurons of the retina after photodamage are primarily related to the content and distribution of the chromatophilic substance and depend on the intensity and duration of illumination.

Huanglian Jiedu decoction alleviates neurobehavioral damage in mice with chronic alcohol exposure through the RAS-RAF-MEK-ERK pathway

ObjectiveLong-term alcohol consumption can cause organic damage to the brain, resulting in mental and nervous system abnormalities and intellectual impairment. Huanglian Jiedu decoction (HLJDD) is the classic representative of clearing heat and detoxifying. This study aimed to explore the effects and possible mechanisms of HLJDD on brain injury in chronic alcohol-exposed mice. MethodsThe alcohol-exposed mice were treated with different doses of HLJDD to observe behavioral changes, hippocampal Aβ1-42 deposition, number and ultrastructural changes of neurons in the hippocampus and prefrontal cortex, and expressions of synaptic proteins. On this basis, transcriptome sequencing was used to analyze the differentially expressed genes in different treatment groups, and functional enrichment analysis was performed. Then, WB and RT-PCR were used to verify the expression of the pathway. ResultsChronic alcohol exposure reduced body weight in mice, led to motor cognitive impairment, increased Aβ1-42 in the hippocampus, decreased the number of neurons in the hippocampus and prefrontal cortex, and the expression of PSD95 and SYN in the hippocampus. HLJDD significantly improved the cognitive dysfunction of mice and alleviated the damage of the hippocampus and prefrontal cortex. Transcriptome sequencing results showed that the regulatory effects of HLJDD on chronic alcohol-exposed mice may be related to the RAS pathway. Further experiments confirmed that chronic alcohol exposure caused a significant increase in protein and gene expressions of the RAS-RAF-MEK-ERK pathway in mouse, and this activation was reversed by HLJDD. ConclusionHLJDD may ameliorate brain damage caused by chronic alcohol exposure by regulating the RAS-RAF-MEK-ERK pathway.

Tetrahydropiperine, a natural alkaloid with neuroprotective effects in ischemic stroke

BackgroundIschemic stroke (IS) is a life-threatening neurological disease with various pathological mechanisms. Tetrahydropiperine (THP) is a natural alkaloid with protective effects against multiple diseases, such as seizure, and pain. This study was to examine the impact of THP on IS and investigate its potential mechanism. Material and methodsWe employed network pharmacology and molecular docking techniques to identify the target proteins of THP for intervention in IS. Adult male Sprague-Dawley rats were used to create a permanent middle cerebral artery occlusion model. PC-12 cells were chosen to establish an oxygen–glucose deprivation (OGD) cell model. Disease modeling followed by nimodipine (NIMO); 3-methyladenine (3-MA) and rapamycin (RAP) interventions. Open field test, Longa score, balance beam test, and forelimb grip test were used to measure motor and neurological functions. The degree of neurological damage recovery was assessed through behavioral analysis, and cerebral infarction volume was determined using TTC staining. Morphological changes were examined through HE and Nissl staining, and ultrastructural changes in neurons were observed using transmission electron microscopy. The protein expression of autophagy and related pathways was analyzed through Western blot (WB). The appropriate hypoxia time and drug concentration were determined using CCK-8 assay, which also measured cell survival rate. ResultsThe network pharmacology findings indicated that the impact of THP on IS was enhanced in the PI3K/Akt signaling pathway. THP demonstrated robust docking capability with proteins associated with the autophagy and PI3K/Akt/mTOR, as indicated by the molecular docking outcomes. THP significantly improved behavioral damage, reduced the area of cerebral infarction, ameliorated histopathological damage from ischemia, increase neuronal survival, and alleviated ultrastructural damage in neurons (P < 0.05). THP enhanced the survival of PC-12 cells induced by OGD and ameliorated the morphological harm to the cells (P < 0.05). THP was found to elevate the quantities of P62, LC3-Ⅰ, PI3K, P-AKt/Akt, and P-mTOR/mTOR proteins while reducing the levels of Atg7 and Beclin1 proteins. The results of transmission electron microscopy showed no autophagosomes in the THP, 3-MA, and 3-MA + THP groups. ConclusionThe activation of the PI3K/Akt/mTOR signaling pathway by THP inhibits autophagy and provides relief from neurological damage in IS.

Brain-aging related protein expression and imaging characteristics of mice exposed to chronic hypoxia at high altitude.

To determine changes in protein expression related to brain aging and imaging features in mice after chronic hypoxia exposure at high altitude. A total of 24 healthy 4-week-old mice were randomly divided into high altitude hypoxia (HH) and plain control (PC) groups (n = 8 per group). HH mice were transported from Xi'an (450 m above sea level) to Maduo (4,300 m above sea level) while PC mice were raised in Xi'an. After 6 months, 7.0T magnetic resonance imaging (MRI) was performed. All mice completed T2-weighted imaging (T2WI), diffusion tensor imaging (DTI), resting-state functional MRI (rs-fMRI), arterial spin labeling (ASL), and magnetic resonance angiography (MRA) examinations. Next, brain slices were prepared and Nissl staining was used to observe morphological changes in neurons. Ultrastructural changes in neurons were observed by transmission electron microscopy. Expression changes of Caspase-3, klotho, P16, P21, and P53 at the gene and protein levels were detected by real-time PCR (RT-PCR) and Western blot. The number of neuronal Nissl bodies in the hippocampus and frontal cortex was significantly decreased in the HH group compared to the PC group. Some hippocampal and frontal cortical neurons were apoptotic, the nuclei were wrinkled, chromatin was aggregated, and most mitochondria were mildly swollen (crista lysis, fracture). Compared with the PC group, the HH group showed elevated expression of caspase-3 mRNA, P16 mRNA, P21 mRNA, and P53 mRNA in the hippocampus and frontal cortex. Expression of Klotho mRNA in the frontal cortex was also significantly decreased. Western blot results showed that caspase-3 protein expression in the hippocampus and frontal cortex of the HH group was increased compared with the PC group. Moreover, there was decreased Klotho protein expression and significantly increased P-P53 protein expression. Compared with the PC group, expression of P16 protein in the frontal cortex of the HH group was increased and the gray matter (GM) volume in the left visceral area, left caudate nucleus, and left piriform cortex was decreased. Furthermore, the amplitude of low frequency fluctuation was decreased in the left posterior nongranular insular lobe, right small cell reticular nucleus, left flocculus, left accessory flocculus, and left primary auditory area, but increased in the GM layer of the left superior colliculus. Regional homogeneity was decreased in the left and right olfactory regions, but increased in the left bed nucleus. After exposure to high altitude, functional connectivity (FC) between the bilateral caudate nucleus and thalamus, corpus callosum, cingulate gyrus, anterior limbic cortex, globus pallidus, and hippocampus was weakened. FC between the right caudate nucleus and hypothalamus and entorhinal cortex was also weakened. The fractional anisotropy value of the left hippocampus was decreased in the HH group. Compared with the PC group, the HH group showed significantly increased inner diameters of the bilateral common carotid artery and left internal carotid artery. The cerebral blood flow values of the bilateral cortex and bilateral hippocampus in the HH group did not change significantly. Taken together, our findings show that chronic hypoxia exposure at high altitude may promote neuronal apoptosis and abnormal expression of related proteins, changing the structure and function of brain. These changes may contribute to brain aging.

Di-Huang-Yin-Zi regulates P53/SLC7A11 signaling pathway to improve the mechanism of post-stroke depression

Ethnopharmacological relevancePost-stroke depression (PSD) is a condition characterized by a profoundly depressed mood and diminished interest following a stroke. Di-Huang-Yin-Zi (DHYZ), a traditional Chinese herbal preparation, gained widespread use and shown favorable outcomes in PSD treatment. However, the combination mechanisms of this formula for PSD remain unclear. Aim of studyThis study aimed to assess the therapeutic effects of DHYZ extract on rats with PSD and further investigate its underlying mechanism. Materials and methodsThe active components of DHYZ extract were quantified by the high-performance liquid chromatography-ultraviolet (HPLC-UV). Neurofunctional and depressive-like behavioral tests were performed to assess the neuroprotective effects of DHYZ extract after establishing a PSD rat model. Brain tissue damage volume was assessed using TTC staining, and transmission electron microscopy (TEM) was used to observe the ultrastructural changes of neurons in the prefrontal cortex region, while cell apoptosis was evaluated through TUNEL assay in the prefrontal cortex region of the brain. The effect of DHYZ on ferroptosis markers includes Fe2+, malondialdehyde (MDA), reactive oxygen species (ROS), and glutathione (GSH) were determined in the brain tissue. Moreover, the expression of key proteins or mRNA levels of the P53/SLC7A11 signaling pathway were detected using Western blot or PCR, respectively. Additionally, P53-constructed overexpression vectors were injected to increase the level of P53. In this series of experiments, ferroptosis markers and key factors of the P53/SLC7A11 signaling pathway were evaluated. ResultsDHYZ extract could increase the sucrose preference of SPT, but decrease the duration of immobility of FST and cortical infarct volume of PSD rats. A TEM study revealed that DHYZ extract improved synaptic ultrastructure in the cortical region of PSD rats. Furthermore, DHYZ treatment effectively decreased ROS and MDA levels, inhibiting the expression of ferroptosis-related markers such as Fe2+, SLC7A11, and GPX4. Additionally, DHYZ promoted the ubiquitination of P53, thus inhibiting its degradation. Notably, AAV-mediated overexpression of P53 reversed the effects of DHYZ on neuroprotection and ferroptosis inhibition in PSD rats. ConclusionsOur results demonstrated that DHYZ extract alleviates the symptoms and enhances the functional capability of PSD rats, mainly by suppressing the ferroptosis through the P53/SLC7A11/GPX4 pathway.

Ultrastructural Changes in Hippocampal Region CA1 Neurons After Exposure to Permissive Hypercapnia and/or Normobaric Hypoxia.

Isolated exposure to intermittent hypoxia and permissive hypercapnia activates signaling mechanisms that induce ultrastructural changes in mitochondria and endoplasmic reticulum, accompanied by the development of maximal ischemic tolerance in neurons under the combined influence of these factors. However, there are a lack of data on the combined impact of these factors on the ultrastructure of neuronal organelles. The present study aims to comparatively assess the ultrastructural changes in neurons following isolated and combined exposure to hypoxia and hypercapnia, as well as to correlate these changes with the neuroprotective potential previously observed for these factors. Following a 15-session course of 30-min exposures to permissive hypercapnia (PCO2≈50mmHg) and/or normobaric hypoxia (PO2≈150mmHg), morphometric assessment was conducted to evaluate the extent of ultrastructural changes in hippocampal neurons (mitochondria, perinuclear space, and granular endoplasmic reticulum). It was found that in hippocampal neurons from the CA1 region, permissive hypercapnia resulted in increased mitochondrial size, expansion of membranous compartments of the granular endoplasmic reticulum, and perinuclear space. Normobaric hypoxia affected only mitochondrial size, while hypercapnic hypoxia specifically widened the perinuclear space. These ultrastructural changes objectively reflect varying degrees of the influence of hypoxia and hypercapnia on organelles responsible for energy metabolism, anti-apoptotic, and synthetic functions of neurons. This confirms the effect of potentiation of their neuroprotective effects under combined exposure and highlights the dominant role of the hypercapnic component in this mechanism.

Epigallocatechin-3-Gallate Ameliorated Iron Accumulation and Apoptosis and Promoted Neuronal Regeneration and Memory/Cognitive Functions in the Hippocampus Induced by Exposure to a Chronic High-Altitude Hypoxia Environment

We aimed to explore the protective effects and potential treatment mechanism of Epigallocatechin-3-gallate (EGCG) in an animal model of chronic exposure in a natural high-altitude hypoxia (HAH) environment. Behavioral alterations were assessed with the Morris water maze test. Iron accumulation in the hippocampus was detected by using DAB enhanced Perls’ staining, MRI, qPCR and colorimetry, respectively. Oxidative stress (malondialdehyde, MDA), apoptosis (Caspase-3), and neural regeneration (brain-derived neurotrophic factor, BDNF) were detected by using ELISA and western blotting. Neural ultrastructural changes were evaluated by transmission electron microscopy (TEM). The results showed that learning and memory performance of rats decreased when exposure to HAH environment. It was followed by iron accumulation, dysfunctional iron metabolism, reduced BDNF and the upregulation of MDA and Caspase-3. TEM confirmed the ultrastructural changes in neurons and mitochondria. EGCG reduced HAH-induced cognitive impairment, iron deposition, oxidative stress, and apoptosis and promoted neuronal regeneration against chronic HAH-mediated neural injury.

PECULIARITIES OF ELECTRON MICROSCOPIC HIPPOCAMPAL FORMATION DEVELOPMENT CHARACTERISTICS IN POSTERITY OF RATS AFTER PGE2 INJECTION FOR LABOR INDUCTION

The aim: To determine the peculiarities of electron microscopic hippocampal formation development characteristics in postetry of rats during two first weeks of postnatal life after intravaginal injection of prostaglandin E2 for labor induction. Materials and methods: The ultrastructural changes of hippocampal formation in posterity of white syngenic rats at the 1st, 7th and 14th days of postnatal life were examined. In this study we used electron-microscopic method. Brain tissue from experimental animals underwent standart stages necessary for electron microscopy and poured into pure Epon. Epon polymerization was carried out in two stages at 36 ° C (12 h) and 56 ° C (24 h). Ultrathin (50-60 nm) sections were obtained on a PowerTome RMC Boeckeler ultratome and then contrasted according to the E. Reynolds method. Ultrathin sections were studied in a PEM-100 electron microscope with an accelerating voltage 60 kV. Results: Based on the obtained data in the study of the hippocampal formation in postery of rats after induction of labor, analysis of the literature devoted to the electron microscopic study of the brain after ischemic injuries, it can be concluded that on the background of stimulation of labor by PgE2, changes corresponding to ischemic damage take place in the rat brain. Conclusions: In posterity of rats after receiving PgE2 for labour induction it was revealed microcirculatory changes; edema of the presynaptic endings, synaptic vesicles aggregation in the center of the presynaptic processes, swelling and destruction of mitochondria; oligodendroglia changes; ultrastructural changes in neurons like edema and vacuolization of mitochondria.

Neurobehavioral and Ultrastructural Changes Induced by Phytosynthesized Silver-Nanoparticle Toxicity in an In Vivo Rat Model.

(1) Background: The study aimed to assess neurobehavioral, ultrastructural, and biochemical changes induced by silver nanoparticles synthesized with Cornus mas L. extract (AgNPs-CM) in rat brains. (2) Methods: The study included 36 male adult rats divided into three groups. Over a period of 45 days, AgNPs-CM (0.8 and 1.5 mg/kg b.w.) were administered daily by gavage to two of the groups, while the control group received the vehicle used for AgNP. After treatment, OFT and EPM tests were conducted in order to assess neurobehavioral changes. Six of the animals from each group were sacrificed immediately after completion of treatment, while the remaining six were allowed to recuperate for an additional 15 days. Transmission electron microscopy (TEM), GFAP immunohistochemistry, and evaluation of TNFα, IL-6, MDA, and CAT activity were performed on the frontal cortex and hippocampus. (3) Results: Treated animals displayed a dose- and time-dependent increase in anxiety-like behavior and severe ultrastructural changes in neurons, astrocytes, and capillaries in both brain regions. Immunohistochemistry displayed astrogliosis with altered cell morphology. TNFα, IL-6, MDA, and CAT activity were significantly altered, depending on brain region and time post exposure. (4) Conclusions: AgNPs-CM induced neurobehavioral changes and severe cell lesions that continued to escalate after cessation of exposure.

ELECTRONIC-MICROSCOPIC CHANGES OF THE INTRAMURAL NERVOUS PLEXUS OF THE DUODENUM IN CONDITIONS OF CHRONIC STRESS

The article presents a study of ultrastructural changes of neurons of the intramural nervous system (muscular- intestinal plexus) of the duodenum under chronic stress. The experiment was performed on 60 white adult male rats. The material was taken from the proximal and distal parts of the duodenum after 14, 28, 56 days of the experiment. For electron microscopic examination, pieces of the duodenum were fi xed in 2.5% glutaraldehyde solution for 4 hours, and then fi xed in 2% osmium tetroxide solution. First, semi-thin sections were made to detect the localization of nerve cells of the musculoskeletal plexus of the duodenum, staining them in 1% methylene blue solution or 0.1% toluidine blue solution. Ultrathin sections were made on an ultramicrotome Tesla BS-490A, the material was studied on an electron microscope TEM – 125 K («Selmi», Ukraine). After 14 days of chronic stress, there is signifi cant damage to the neurons of the musculoskeletal plexus of the duodenum due to reactive and edematous processes, accompanied by the development of ultrastructural changes and the death of some neurons. After 28-56 days of the experiment, edematous, dystrophic- destructive processes in nerve cells are further observed, but in some of them there are a number of compensatory- adaptive and reparative processes aimed at restoring impaired functions.

Pathogenesis of Neurological and Mental Disorders in Patients with Covid-19: Possible Role of Reactive Nitrogen and Oxygen Species

The pathogenesis of neuronal and mental disorders are analyzed according to the literature and compared with other neuronal damage during hypoxia/ischemia, inflammatory processes, and immune/autoimmune diseases. The free radical component of the development of the pathogenesis of COVID-19 is analyzed, which is activated at all stages of the disease, starting with the first manifestations of inflammatory reactions, during the development of a «cytokine storm», hypoxia/ischemia, as well as activation of immune/autoimmune reactions and processes. These free radical components are realized against the background of disruption of the cycles of nitric oxide and superoxide anion radical, and, leads to the formation of extremely high concentrations of very active radicals of nitrogen dioxide (NO2 ), OH-radicals, peroxynitrites. As a result of these processes, nonspecific reactions are activated that are characteristic of the development of any typical pathological process, which is a common component of almost all known pathological processes. It is suggested that the similarity of structural and ultrastructural changes in neurons and glial cells of the brain during hypoxia/ischemia, glutamate neurotoxicity, traumatic brain injury have similarities with those changes that are characteristic of all stages of COVID-19 development and are due to the activation of oxidative and nitrosative stress and increased formation of highly reactive nitrogen species (RNS) and reactive oxygen species (ROS) capable of damaging almost all molecular, biochemical and chemical components of cells.

Protective effects of Cerebralcare Granule® against the learning and memory impairment in a mouse model of Alzheimer's disease

Alzheimer's disease (AD) is an age‐related neurodegenerative disorder characterized by the impairment of cognition, memory, language and behavioral function. So far, there are no efficacious drugs approved for the treatment of AD. Cerebralcare Granule (CG) is a compound Chinese medicine used for treatment of headache and dizziness associated with cerebrovascular diseases. Increasing evidence indicates that CG can improve the cerebral microcirculatory disturbance and has a protective effect on the neural damage, which suggests CG may be a promising medicine for AD.Herein, this study investigated the potential effect of CG on AD in the Senescence Accelerated Prone Mouse 8 (SAMP8) mouse. Male 7‐month‐old SAMP8 mice were randomly divided into five groups: AD model group, CG treatment groups (935, 1870 and 3740 mg/kg), and donepezil treatment group (1.3 mg/kg). After intragastric administration with CG for two months, behavioral tests were conducted to evaluate the neuroprotective effects of CG. Ultrastructural changes of neurons and synapses in the hippocampus of the mice were observed. The expressional levels of BDNF, NGF, and TrkA were analyzed through immunohistochemistry. Western blotting was used to analyze the expressional levels of GAP‐43, SYP, and PSD‐95. Biochemical analysis was performed to assess the activities of total antioxidant capacity (T‐AOC), SOD, and GSH‐Px, and the content of GSH and MDA.The findings showed that CG dose‐dependently attenuated the impairment of spontaneous alternation behavior and donepezil treatment had a significant effect in attenuating the impairment of spontaneous alternation behavior. The mice in the CG‐treatment groups (1870 and 3740 mg/kg) consistently took a less time to find the platform than the model group in the Morris water maze test. CG and donepezil treatment alleviated the synaptic ultrastructure damage in the hippocampal CA1 region of the SAMP8 mouse and normal synaptic morphology and structure was maintained. CG can increase the levels of activities of GSH (change ratio of 45.5%), T‐AOC (change ratio of 40.9%), SOD (change ratio of 171.9%) and GSH‐Px (change ratio of 117.4%), and decrease the content of MDA (change ratio of 60.7%). Compared with the model group, the group with 3740mg/kg CG showed a significantly increased expression of SYP and PSD‐95 in the hippocampus and cerebral cortex. The group treated with either 3740 mg/kg CG or with donepezil showed a significantly increased expression of BDNF(change ratio of 38.2%), NGF (change ratio of 41.9%) and the neurotrophic factor receptor TrkA (change ratio of 46.9%), compared with the model group.The above results suggest that CG can alleviate the learning and memory impairment of AD mice via inhibiting oxidative stress, increasing neurotrophic factors and mitigating synaptic damage.Support or Funding InformationSupported by Tianjin Science and Technology's Plan (16PTSYJC00270).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The effects of ginsenoside Rg1 on chronic stress induced depression-like behaviors, BDNF expression and the phosphorylation of PKA and CREB in rats

Depression is a common neuropsychiatric disorder which has been associated with a wide range of structural and functional changes within specific brain regions. Ginsenoside Rg1 has been shown to exert a number of neuroprotective effects as demonstrated in various in vivo and in vitro studies. However, little information is available regarding the site and mechanisms of ginsenoside Rg1 in promoting antidepressant effects. The present study aimed to investigate the neuroprotective and ameliorating effects of ginsenoside Rg1 on depression-like behavior as induced by chronic unpredictable mild stress (CUMS). The results showed that CUMS was effective in producing depression-like behaviors in rats as indicated by decreased responses in sucrose preference and forced swim tests which were associated with ultrastructural changes in neurons within the amygdala. Moreover, levels of PKA and CREB phosphorylation and the expression of brain-derived neurotrophic factor (BDNF) were decreased in the amygdala of CUMS rats. Remarkably, chronic ginsenoside Rg1 (40mg/kg, i.p., 5weeks) treatment significantly ameliorated these behavioral and biochemical alterations associated with CUMS-induced depression. Taken together, the results of the present study demonstrate that ginsenoside Rg1 exhibits antidepressant-like effects against CUMS-induced depression. This amelioration of depression-like behaviors by ginsenoside Rg1 appears to be mediated, at least in part, by a CREB-regulated increase of BDNF expression in the amygdala of rats. Therefore, these findings reveal the therapeutic potential of ginsenoside Rg1 for use in clinical trials in the treatment of depression.

The Possible Damaged Mechanism and the Preventive Effect of Monosialotetrahexosylganglioside in a Rat Model of Cerebral Ischemia-Reperfusion Injury

The pathogenesis of cerebral ischemia-reperfusion injury (CIRI) is not completely clear and therapies are limited now. Therefore, our study aimed to investigate the possible pathogenesis and preventive approach of CIRI through analyzing changes of aspartate (Asp), glutamate (Glu), mitochondrial calcium (MCa), calmodulin (CaM), and malondialdehyde (MDA) contents and ultramicropathology in hippocampus and cerebral cortex of ischemic susceptible injured regions and the effect of monosialotetrahexosylganglioside (GM1) in the rat model of CIRI. Contents of Asp, Glu, MCa, CaM, and MDA in hippocampus and cerebral cortex tissues were measured by a high-performance liquid chromatography, atomic absorption spectrophotometer, and ordinary spectrophotometer, respectively, changes of ultramicrostructure in neurons of the hippocampus CA1 region and frontal cerebral cortex were observed by a transmission electron microscope. Contents of Asp and Glu in hippocampus and cerebral cortex tissues of CIRI groups significantly decreased and contents of MCa, CaM, and MDA significantly increased than those in control groups, and the ultramicrostructure in neurons of the hippocampus CA1 region and frontal cerebral cortex revealed a significant damaged change, and GM1 significantly ameliorated changes of Asp, Glu, MCa, CaM, and MDA contents in hippocampus and ultrastructural changes in neurons of the hippocampus CA1 region and frontal cerebral cortex. Our findings further support that the abnormal release and/or reuptake of excitatory amino acid neurotransmitters, the disordered calcium homeostasis and the excessive production and/or reduced elimination of reactive oxygen species contribute to the pathogenesis of CIRI, and GM1 can partially prevent these pathogenesises to exert the protective effect on CIRI.

Effects of curcumin on chronic, unpredictable, mild, stress-induced depressive-like behaviour and structural plasticity in the lateral amygdala of rats

Depression is a neuropsychiatric disease associated with wide ranging disruptions in neuronal plasticity throughout the brain. Curcumin, a natural polyphenolic compound of curcuma loga, has been demonstrated to be effective in the treatment of depressive-like disorders. The present study aimed to investigate the mechanisms underlying the antidepressant-like effects of curcumin in a rat model of chronic, unpredictable, mild, stress (CUMS) -induced depression. The results showed that CUMS produced depressive-like behaviours in rats, which were associated with ultra-structural changes in neurons within the lateral amygdala (LA). In addition, the expression of synapse-associated proteins such as brain-derived neurotrophic factor (BDNF), PSD-95 and synaptophysin were significantly decreased in the LA of CUMS-treated rats. Chronic administration of curcumin (40 mg/kg, i.p. 6 wk) before stress exposure significantly prevented these neuronal and biochemical alterations induced by CUMS, and suppressed depressive-like behaviours, suggesting that this neuronal dysregulation may be related to the depressive-like behaviours caused by CUMS. Together with our previous results, the current findings demonstrate that curcumin exhibits neuroprotection and antidepressant-like effects in the CUMS-induced depression model. Furthermore, this antidepressant-like action of curcumin appears to be mediated by modulating synapse-associated proteins within the LA. These findings provide new insights into the underlying mechanisms leading to neural dysfunction in depression and reveal the therapeutic potential for curcumin use in clinical trials.

Effect of fish oil on postoperative fatigue of rats subject to open abdominal surgery: implications and mechanisms

Objective To investigate the effects of fish oil on postoperative fatigue (POF) and the action mechansims.Methods Twenty-four SD rats were randomly divided into control group ( group C,n =8 ),surgery group (group S,n =8 ) and fish oil treatment group (group F,n =8 ).Postoperative behaviours were observed.Serum levels of interleukin (IL) -1-β,IL-6,tumor necrosis factor (TNF) -α,superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were determined.Histological changes and ultrastructural changes of neurons in the hippocampus were examined with Hematoxylin and Eosin (HE) staining,and under an electron microscope.The central levels of 5-hydroxytryptamine (5-HT),dopamine (DA) and norepinephrine (NE) were measured by high-performance liquid chromatography-fluorescence.Results Histological and ultrastructural lesions in group F were milder than in group S.The contents of neurotransmitters were different.The levels of IL-1-β,IL-6 and TNF-α in group S [ (60.02 ± 11.08 ),(50.13 ±4.45),(41.08 ±2.17) ng/L]and group F [(45.48 ±13.51),(42.08 ±4.47),(38.76 ±2.41) ng/L]were higher than those in group C (P＜0.01),and those in group F were lower than in group S ( P ＜ 0.01 ) ; The levels of SOD and GSH-PX in group F were higher than in group S (P ＜ 0.01 ).The results for Morris water maze in group F were superior to those in group S ( P ＜ 0.05 ).Conclusion Fish oil could effectively ameliorate the postoperative inflammatory reaction,reduce damage to antioxidant defense system,alleviate the central stress,and improve POF. Key words: Open abdominal surgery; Postoperative fatigue; Fish oil; Inflammatory

Targeted gene delivery to the mouse brain by MRI-guided focused ultrasound-induced blood–brain barrier disruption

This study aimed to investigate the feasibility of targeted gene transfer into central nervous system (CNS) by MRI-guided focused ultrasound-induced blood–brain barrier (BBB) disruption. Before each sonication, T2-weighted images were obtained to select the target region. Followed by injecting DNA-loaded microbubbles into the tail vein, sonication was performed. The state of local BBB, distribution of plasmid DNA through the opened BBB, the ultrastructural changes of neurons and BDNF expression were detected. The results showed that MRI-guided focused ultrasound (FUS) could accomplish noninvasive, transient, and local BBB disruption, at 1h after sonication, plasmid DNA across the opened BBB had been internalized into the neurons presenting heterogeneous distribution and numerous transparent vesicles were observed in the cytoplasm of the neurons at the sonicated region, suggesting vesicle-mediated endocytosis. At 48h after sonication, the expressions of exogenous gene pBDNF-EGFP were observed in the cytoplasm of some neurons, and BDNF expressions were markedly enhanced by the combination of ultrasound and pBDNF-EGFP-loaded microbubbles about 20-fold than that of the control group (P<0.01). The method by using MRI-guided FUS to induce the local BBB disruption could accomplish effective targeted exogenous gene transfer in CNS. This technique may provide a new option for the treatment of various CNS diseases.

Ultrastructural Changes in Neurons of Medullary Giant-Cell Nucleus in Growing Rat Exposed to Acute Stress

Ultrastructural transformations in neurons of the medullary giant-cell reticular nucleus of young rats during exposure to acute emotional and painful stress attest to activation of the protein synthesis system (nucleolar hypertrophy, well-developed elements of the granular endoplasmic reticulum, increased content of free ribosomes and polysomes) in the majority of cells and the appearance of organelle injuries in some these cells.

Amitriptyline-induced ultrastructural changes in various structures of rat brain

The immediate effect of amitriptyline on various brain structures is characterized by the standard ultrastructural changes in neurons: emergence of numerous coated vesicles in the cytoplasm and formation of cisternae within a 3-h period. These changes are most pronounced in the sensorimotor cortex. Changes in the structure of cytoplasmic organelles are reversible; they disappear 24 h after administration of amitriptyline. Astrocytes respond to the preparation by activation of lysosomes, being the most sensitive cell type of the neuroglia. Numerous synaptic vesicles are seen in the axodendritic synapses. Newly formed fibers in the neuropile may be associated with the antidepressant effect of amitriptyline.

Ultrastructural evidence that mercuric chloride lowers the threshold for glutamate neurotoxicity in an organotypic culture of rat cerebellum

Separate exposure of organotypic cultures, derived from newborn rat cerebellum, to non-toxic concentration of either 100 μM glutamate (GLU) or 1 μM mercuric chloride (MC), for as long as 3 days, produced no distinct ultrastructural changes in neurons and glial cells. By contrast, simultaneous exposure to both agents resulted, as early as after 30 min, in microvacuolar degeneration of neurons and later on in postsynaptic abnormalities, typically accompanying excitotoxic lesions but not heavy metal-induced lesions. The results indicate that MC at low micromolar concentrations lowers the threshold for GLU neurotoxicity.