Changes In Glial Cells Research Articles

Temporal and Spatial Changes in Glial Cells During Chronic Hypobaric Hypoxia: Role in Neurodegeneration

Ascend to high altitude results in a drastic change in the environmental conditions an individual is exposed to. As the altitude increases there is a decrease in partial pressure of oxygen leading to a unique condition known as hypobaric hypoxia (HH). Brain is highly vulnerable to hypoxia and it has been well established that hypobaric hypoxia leads to neurodegeneration in different brain regions. However, the response of glial cells during hypobaric hypoxia needs to be explored yet. The present study was aimed to understand the role of glial cells viz. astrocytes, microglia and oligodendrocytes in HH-induced neuronal death. The study aims to understand the effect of HH exposure on glial physiology in a time-dependent (0, 1, 3, 7 and 14 days of HH exposure) and region-dependent (CA1, CA3 and DG regions of hippocampus) manner. We examined the morphological changes and activation of glial cells along with pro-inflammatory cytokine levels. Results indicated that chronic hypobaric hypoxia (7 and 14 days exposure) causes activation of both astrocytes (GFAP-positive cells) and microglia (IBA-1-positive cells) but oligodendrocytes (M-PLP-positive cells) expression was found to be significantly reduced. The results obtained were found to be more profound in the CA1 region of hippocampus, indicating its vulnerability to hypoxia. Neuroinflammation was suggested by elevated IL-β1, IL-6 and TNF-α cytokine levels upon chronic HH. The study also explored the role of microglia and A1 astrocyte interplay in HH-induced neurodegeneration and demyelination. This study explores the shift in role of glial cell toward neurodegeneration under chronic hypobaric hypoxia stress. Chronic stress results in glial activation which leads to neuroinflammation a plausible factor in HH-induced neurodegeneration.

Tau pathology and neurochemical changes associated with memory dysfunction in an optimised murine model of global cerebral ischaemia - A potential model for vascular dementia?

Cerebral ischemia is known to be a major cause of death and the later development of Alzheimer's disease and vascular dementia. However, ischemia induced cellular damage that initiates these diseases remain poorly understood. This is primarily due to lack of clinically relevant models that are highly reproducible. Here, we have optimised a murine model of global cerebral ischaemia with multiple markers to determine brain pathology, neurochemistry and correlated memory deficits in these animals. Cerebral ischaemia in mice was induced by bilateral common carotid artery occlusion. Following reperfusion, the mice were either fixed with 4% paraformaldehyde or decapitated under anaesthesia. Brains were processed for Western blotting or immunohistochemistry for glial (GLT1) and vesicular (VGLUT1, VGLUT2) glutamate transporters and paired helical filament (PHF1) tau. The PHF1 tau is the main component of neurofibrillary tangle, which is the pathological hallmark of Alzheimer's disease and vascular dementia. The novel object recognition behavioural assay was used to investigate the functional cognitive consequences in these mice. The results show consistent and selective neuronal and glial cell changes in the hippocampus and the cortex together with significant reductions in GLT1 (***P < 0.001), VGLUT1 (**P < 0.01) and VGLUT2 (***P < 0.001) expressions in the hippocampus in occluded mice as compared to sham-operated animals. These changes are associated with increased PHF1 (***P < 0.0001) protein and a significant impairment of performance (*p < 0.0006, N = 6/group) in the novel object recognition test. This model represents a useful tool for investigating cellular, biochemical and molecular mechanisms of global cerebral ischaemia and may be an ideal preclinical model for vascular dementia.

Long-term reconstruction of foveal microstructure and visual acuity after idiopathic macular hole repair: three-year follow-up study

AimsTo evaluate long-term reconstructive changes in foveal microstructures and their associations with visual improvement in eyes with surgically closed macular holes (MHs).MethodsTwenty-eight eyes of 28 patients who underwent successful idiopathic...

S13-3. Glial dysfunction and eplileptogenicity

Temporal lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy, partly characterized by hippocampus sclerosis. Recent accumulating evidence show that changes in glial cells are obvious in TEL, but an involvement of glial changes in TLE is still a matter of debate. Here, we show that status epilepticus (SE) induced activation of microglia, followed by induction of “epileptogenic astrocytes” in the hippocampus. Pilocarpine (Pilo) was used to induce SE in male adult B6 mice. Morphological and functional changes in glia were assessed by immunohistochemical analysis and Ca2+ imaging in the hippocampal slices, respectively. Pilo increased a fast and transient microglial activation (1–3 days after SE), which was followed by sustained activation of astrocytes in the hippocampus (7–28 days after SW). Twenty-eight days after SE, the mice showed susceptibility to Pilo, suggesting induction of epileptogenicity. At this time point, reactive astrocytes displayed excess Ca2+ excitability, reduction of which resulted in inhibition of epileotogenicity. Taken together, after SE, astrocytes become “epileptogenic astrocytes”, whose aberrant Ca2+ excitability should be a cause of epileptogenicity.

APOPTOSIS OF BRAIN CELLS IN EPILEPTIC FOCUS AT PHAPMACRESISTANT TEMPORAL LOBE EPILEPSY

Relevance. Search of the causes of epilepsy and development of new methods of its correction is the most important problem of modern neurology. Studies in recent years focus on examining the role of neuronal apoptosis in epilepsy, the question of the death of glial cells remains poorly understood. However, it is the interaction of neurons with glia that modulates physiological brain function and underlies many neurological diseases, indicating the importance of comprehensive study of the morphological and functional status of these cells in epilepsy. Purpose. To assess the signifi cance of apoptotic death of neurons and glia in the pathogenesis of pharmacoresistant temporal lobe epilepsy by the expression of caspase-3 in brain cells and ultrastructural manifestations. Materials and methods. The objects of the study are the samples of the cortex and white matter of the brain in the area of epileptic foci from 20 patients with pharmacoresistant temporal lobe epilepsy. The material for the comparison group obtained at autopsy from 6 patients without epilepsy. Performed studies were immunohistochemical reactions with antibodies to caspase-3 and ultrastructural biopsy analyses. Results. In every case (100%) patients with E revealed the expression of caspase-3 in gliocytes with predominant localization in the cortex of the temporal lobe. The expression of caspase-3 in neurons has been detected in 20% of observations in single cells. In the comparison group, the expression of caspase-3 was observed only sporadically in a cortical gliocytes. Using electron microscopy we identifi ed a large number of neurons in the cortex with signs of apoptosis at different stages of this process’ development. Apoptotic changes in glial cells were predominantly observed in oligodendrocytes both in the cortex and white matter of the brain. Conclusion. Detected expression of caspase-3 in gliocytes of the cortex and white matter of epileptic foci attests to the active participation of glia in the pathogenesis of epilepsy. By electron microscopy we found that the majority of apoptotically dying glial cells are oligodendrocytes, that in particular explains the known phenomenon of myelin damage in epileptic foci. As a fact, electron microscopic detection of a large number of apoptosis neurons in biopsies of the cortex with lowlevel expression of caspase-3 in them may indicate a different nature of neuronal apoptosis. Thus, glio-neuronal apoptosis in pharmacoresistant epilepsy has a signifi cant manifestation, and this affects the progression of the disease, creating conditions for the development of status epilepticus and cognitive disorders. Further study of this issue offers the prospect of new therapeutic strategies in the treatment of epilepsy.

A Single Intraperitoneal Injection of Endotoxin Changes Glial Cells in Rats as Revealed by Positron Emission Tomography Using [11C]PK11195.

Intracranial administration of lipopolysaccharide (LPS) is known to elicit a rapid innate immune response, activate glial cells in the brain, and induce depression-like behavior. However, no study has focused on the changes in glial cells induced by intraperitoneal injection of LPS in vivo. Ten adult male Fischer F344 rats underwent [11C]PK11195 PET before and 2days after intraperitoneal injection of LPS to evaluate the changes in glial cells. The difference in standardized uptake values (SUV) of [11C]PK11195 between before and after injection was determined. There was a cluster of brain regions that showed significant reductions in SUV. This cluster included the bilateral striata and bilateral frontal regions, especially the somatosensory areas. Changes in activity of glial cells induced by the intraperitoneal injection of LPS were detected in vivo by [11C]PK11195 PET. Intraperitoneal injection of LPS is known to induce depression, and further studies with [11C]PK11195 PET would clarify the relationships between neuroinflammation and depression.

Reactive changes in morphological and morphometric parameters of immunopositive astrocytes of the amygdala in response to hormone level in absence epilepsy

To study the changes in the morphological and morphometric parameters of immunopositive astrocytes of the amygdala in absence epilepsy depending on hormonal profile. Adult female WAG/Rij rats were used as experimental subjects. The astrocytes were detected on serial sections using a reaction to glial fibrillary acidic protein (GFAP) with pre-stained hematoxylin. Quantitative analysis was carried out for a 204.8´153.6 μm2 field of view. In the control group, astrocytes had a relatively regular stellate form and GFAP was moderately expressed in their bodies and processes. The number of astrocytes was 18.20±2.87, and their area was 164±3.29 μm2. After ovariectomy, a high expression of the protein, both in the bodies and in the processes of astrocytes, increasing the cell size to 188.85±4.97 μm2 (p<0.05) was observed. The astrocytes increased to 34.55±3.03 (p<0.05). In addition, the deformation of the processes and their diffuse defibration were observed. After hormone replacement therapy, a decrease in GFAP expression was detected, the area of astrocytes became smaller in comparison with the group after ovariectomy: 173.54±5.48 μm2 (p<0.05). Morphological changes in glial cells were manifested as a decrease in the size of their bodies, the processes became smooth without diffuse sprouting and swelling, which is probably associated with neuroprotective functions of estradiol. Thus, the results of our study demonstrated that the deficiency of female sex hormones led to the increase in both the amount and area of astrocytes in the anterior cortical nucleus of the amygdala, and hormone replacement therapy positively affected the structural and quantitative characteristics of astrocytes due to the endogenous protective role of estradiol.

Electrophysiological method of diagnosis of liver encephalopathy in patients with pancreatitis

Acute pancreatitis(AP) remains one of the most urgent issues of modern urgent abdominal surgery. The incidence of AP from year to year is steadily increasing and varies from 23.8 to 58.0% per year. Hepatic renal failure is noted in every fourth patient with severe pancreatitis, which greatly impairs the results of treatment and is the direct cause of death in 40% of cases. Early diagnosis of patients with AP should include detection of hepatic encephalopathy in the latent stage for timely correction of liver failure events. In patients with swollen and destructive pancreatitis, functional deficiency of the liver develops, which greatly complicates the course of the disease and worsens its prognosis. Especially important is the detection of latent AP, which is diagnosed with special psychometric tests, whereas in the standard test of mental status, patients exhibit a norm. The characteristic features of the method for registering indicators of critical frequency of fusion fusion are analyzed. The critical flicker flicker frequency (CFFF) is the maximum frequency of flashes of light that is perceived by the subjects as individual flashing. The method of CFFF is based on the fact that changes in retinal glial cells are similar to those in astrocytes of the brain and are used to determine the latency of AP and severity of apparent hepatic encephalopathy. Allows non-invasive precision, short-range, and reproducible measurements of flicker frequencies. The exclusion criteria for the CFFF test were mental and cerebrovascular diseases, blindness and color blindness. The critical fission fusion rate has been determined in 46 patients with moderately severe and severe acute pancreatitis. Indicators were compared with indicators of the regional norm. The necessity of application of the method of determination of CFFF in acute pancreatitis for the early diagnosis of latent hepatic encephalopathy is substantiated. The validity of the method for the determination of CFFF at different stages of patient monitoring has been confirmed. The substantiated intensive therapy was supplemented with the introduction of LoLa and timely correction of the latent PE phenomena was achieved, which allowed to correct the metabolic disturbances more quickly and reduce the manifestations of endogenous intoxication.

Intermittent theta-burst stimulation rescues dopamine-dependent corticostriatal synaptic plasticity and motor behavior in experimental parkinsonism: Possible role of glial activity.

Recent studies support the therapeutic utility of repetitive transcranial magnetic stimulation in Parkinson's disease (PD), whose progression is correlated with loss of corticostriatal long-term potentiation and long-term depression. Glial cell activation is also a feature of PD that is gaining increasing attention in the field because astrocytes play a role in chronic neuroinflammatory responses but are also able to manage dopamine (DA) levels. Intermittent theta-burst stimulation protocol was applied to study the effect of therapeutic neuromodulation on striatal DA levels measured by means of in vivo microdialysis in 6-hydroxydopamine-hemilesioned rats. Effects on corticostriatal synaptic plasticity were studied through in vitro intracellular and whole-cell patch clamp recordings while stepping test and CatWalk were used to test motor behavior. Immunohistochemical analyses were performed to analyze morphological changes in neurons and glial cells. Acute theta-burst stimulation induced an increase in striatal DA levels in hemiparkinsonian rats, 80 minutes post-treatment, correlated with full recovery of plasticity and amelioration of motor performances. With the same timing, immediate early gene activation was restricted to striatal spiny neurons. Intense astrocytic and microglial responses were also significantly reduced 80 minutes following theta-burst stimulation. Taken together, these results provide a first glimpse on physiological adaptations that occur in the parkinsonian striatum following intermittent theta-burst stimulation and may help to disclose the real potential of this technique in treating PD and preventing DA replacement therapy-associated disturbances. © 2017 International Parkinson and Movement Disorder Society.

Preparation of Primary Mixed Glial Cultures from Adult Mouse Spinal Cord Tissue.

It has been well-accepted that spinal cord glial responses contribute significantly to the development of neuropathic pain. Tremendous information regarding glial activities at the cellular and molecular levels has been obtained through in vitro cell culture systems. The in vitro systems utilized, mainly include primary glia derived from neonatal brain cortical tissue and immortalized cell lines. However, these systems may not reflect the characteristics of spinal cord glial cells in vivo. In order to further investigate the roles of spinal cord glial cells in the development of peripheral nerve injury-induced neuropathic pain using a culture system that better reflects the in vivo condition, our laboratory has developed a method to establish primary spinal cord mixed glial cultures from adult mice. Briefly, spinal cords are collected from adult mice and processed through papain digestion followed by myelin removal with a density-gradient medium. Single cell suspensions are cultured in complete Dulbecco's modified Eagle media (cDMEM) supplemented with 2-mercaptoethanol (2-ME) at 35.9 oC. These culture conditions were optimized specifically for the growth of mixed glial cells. Under these conditions, cells are ready to be used for experimentation between 12 - 14 d(cells are usually in log phase during this time) after the establishment of the culture (D 0) and can be kept in culture conditions up to D 21. This culture system can be used to investigate the responses of spinal cord glial cells upon stimulation with various substances and agents. Besides neuropathic pain, this system can be used to study glial responses in other diseases that involve pathological changes of spinal cord glial cells.

The effect of α-synuclein on gliosis and IL-1α, TNFα, IFNγ, TGFβ expression in murine brain

Alpha - synuclein (ASN) is the principal component of Lewy pathology and strongly influences on the pathogenesis of Parkinson's disease (PD). The increased level of ASN protein causes microglial response. The reactive microglial cells may actively participate in the damaging of dopaminergic neurons. The data suggests that ASN accumulation in astrocytes might damage these cells in the substantia nigra pars compacta (SN) and promotes degeneration of dopaminergic neurons in SN. We examined the potential role of recombinant ASN monomers as a major pathogenic factor causing the inflammatory response in the central nervous system. Mice were bilaterally infused by human ASN monomers into the striatum (ST) or SN (single treatment was 4μg/structure, 8μg per brain) and decapitated after 1, 4 or 12 weeks post injection. The changes in the level of inflammatory factors in ST were evaluated using Real-Time PCR and Western Blot method. The analysis of morphological changes of glial cells was performed by immunohistochemical staining. We observed a strong activation of microglia cells in ST and increased expression of striatal interleukin 1α, tumor necrosis factor alpha and interferon gamma after ASN injection into the ST. We noticed an increase in striatal glial fibrillary acidic protein mRNA level 4 weeks after ASN injection into the ST. Injection of ASN into the SN led to an increase of striatal transforming growth factor beta mRNA level and has no influence on striatal glial fibrillary acidic protein mRNA level. Our results suggest that both the microglia activation and supressing astrocytes play a crucial role in ASN-related dopaminergic neurotoxicity.

Flavonoid quercetin reduces gliosis after repetitive mild traumatic brain injury in mice

The effect of water-soluble form of quercetin on the structural changes of glial cells in hippocampus was investigated in mice after repetitive mild traumatic brain injury. Reactive astro- and microgliosis in hippocampus were observed after brain injury. Iba 1 and GFAP immunohistochemistry was used to visualize astrocytes and microglia cells. Immunopositive cells were counted in hippocampal CA 1-area at 5th, 10th and 30th days since thefirst injury and at 5th, 10th and 30th days since thefirst quercetin injection. Administration of quercetin leaded to the decrease in number of activated glial cells. Thus, our study demonstrates thefollowing: repetitive mild traumatic brain injury in mice is associated with reactive gliosis; quercetin showed neuroprotective effects by reducing this gliosis. In view of the described, use of quercetin is appropriate for pharmacological correction of cerebrovascular disorders after traumatic brain injury.

Establishment of brain edema model of rats with intracerebral hemorrhage by IV collagenase combined with autologous blood

Objective To explore the model of IV combined with autologous blood to build a model of compound brain edema in rats, and provide experimental evidence for the related research of brain edema. Methods 180 SD rats were randomly divided into 6 groups: Group A (IV collagenase + autologous coagulation blood + autologous blood coagulation), group B (autologous coagulation), group C (IV collagenase), group D (autologous anti coagulation), E group (blank control), F group (sham operation). Group A, B, C, D were modeled, Group E was not given treatment, Group F was injected with normal saline.Neurological deficit was evalated by longa/Bederson and physical symmetry test score.The water content in brain tissue was detected by wet and dry weight method.K+ , Na+ , Ca2+ were detected by atomic absorption spectrometry.The ultrastructural changes of glial cells were observed by transmission electron microscope (TEM). Glial cells were identified by immunofluorescence assay.FCM and TUNEL tested the apoptosis of glial cells.CCK-8 and EDU tested the proliferation of glial cells.Real time quantitative polymerase chain reaction and Western blot were used to measure matrix metalloproteinase-9(MMP-9) in glial cells and water channel protein 4(AQP4) mRNA and protein expression.The scratch test and Transwell assayed glial cell migration and invasion. Results Comparison among groups: Longa /Bederson score of Neurologic impairment, Brain tissue water content, electrolyte Na+ was the highest level of group A, electrolyte K+ , Ca2+ at least.The apoptosis of group A was the most(32.27±3.33), the least proliferation(5.33±1.14), migration and invasion ability were the weakest(85.35±8.11; 8.08±1.96); mRNA(9.31±0.84; 15.69±1.77) and protein(4.25±0.27; 4.34±0.33) of MMP-9 and AQP4 were the most significant in group A (P<0.05). Conclusion IV collagenase combined with autologous blood to build a model of brain edema animal model makes the brain edema markers MMP-9 and AQP4 stronger, and the functional changes of cytology is more significant. Key words: Cerebral hemorrhage; Brain edema; Experiment; MMP-9; AQP4

Expression Pattern of Scavenger Receptors and Amyloid-β Phagocytosis of Astrocytes and Microglia in Culture are Modified by Acidosis: Implications for Alzheimer's Disease.

The pathological hallmarks of Alzheimer's disease (AD) are amyloid-β (Aβ) plaques, neurofibrillary tangles, and glia activation. The pathology also includes vascular amyloidosis and cerebrovascular disease. Vascular compromise can result in hypoperfusion, local tissue hypoxia, and acidosis. Activated microglia and astrocytes can phagocytose Aβ through membrane receptors that include scavenger receptors. Changes in glial cells induced by extracellular acidosis could play a role in the development of AD. Here, we assess whether extracellular acidosis changes glial cell properties relevant for Aβ clearance capacity. Incubation of glial cells on acidified culture medium (pH 6.9 or 6.5) for 24-48 h resulted in decreased cell diameter, with thinner branches in astrocytes, slight reduction in cell body size in microglia, a transient decrease in astrocyte adhesion to substrates, and a persistent decrease in microglia adhesion compared with control media (pH 7.4). Astrocyte Aβ phagocytosis decreased at pH 6.9 and 6.5, whereas microglia phagocytosis only transiently decreased in acidified media. Scavenger receptors class B member I (SR-BI) increased and scavenger receptors-macrophage receptors with collagenous structures (SR-MARCO) decreased in astrocytes cultured at pH 6.5. In contrast, in microglia exposed to pH 6.5, expression of SR-BI and SR-MARCO increased and fatty acid translocase (CD-36) decreased. In conclusion, the acidic environment changed the adhesiveness and morphology of both microglia and astrocytes, but only astrocytes showed a persistent decrease in Aβ clearance activity. Expression of scavenger receptors was affected differentially in microglia and astrocytes by acidosis. These changes in scavenger receptor patterns can affect the activation of glia and their contribution to neurodegeneration.

Involvement of CCL3/CCR5 Signaling in Dorsal Root Ganglion in Remifentanil-induced Hyperalgesia in Rats.

Several mechanisms of remifentanil-induced hyperalgesia in spinal cord mainly have been explained such as N-methyl-D-aspartate receptors activation, but the mechanism in dorsal root ganglion (DRG) is poorly understood. It has been reported that CCL3 may be a regulator in both inflammatory pain and hyperalgesia. In this paper we explored whether CCL3 and CCR5, the mainly receptor of CCL3, play a role in the remifentanil-induced hyperalgesia in DRG by using a rat model with remifentanil administration. The von Frey test and hot plate test were performed to measure the different threshold to evaluate mechanical and thermal hyperalgesia. Real-time polymerase chain reaction and Western blot analysis were used to evaluate time course of CCL3 and CCR5 expression in DRG after remifentanil infusion. The changes of glial cells and the expression of CCL3 and CCR5 were detected by immunofluorescence assay. Finally, intrathecal injection of CCL3-neutralizing antibody and maraviroc, the CCR5 antagonists, were used sevoflurane to confirm the role of CCL3/CCR5 signaling in the rat model of remifentanil-induced hyperalgesia. Remifentanil infusion profoundly increased thermal and mechanical hyperalgesia from 2 to 48 hours according to paw withdrawal latency (PWL) and paw withdrawal thresholds (PWT) (mean±SD, hyperalgesia vs. control, 17.4±0.91 vs. 8.5±1.46 s; 20.1±0.32 vs. 9.6±0.5 g, n=8). Moreover, the expression of mRNAs and proteins of CCL3 and its receptor CCR5 in DRG were dramatically increased after remifentanil infusion as compared with the normal saline group. We also found that CCL3 and CCR5 were colocalized with glial cells or neurons. Furthermore, intrathecal injection of CCL3-neutralizing antibody (mean±SD, hyperalgesia vs. control, 17.4±0.91 vs. 8.5±1.46 s; 20.1±0.32 vs. 9.6±0.5 g, n=5) and maraviroc(mean±SD, hyperalgesia vs. control, 17.4±0.91 vs. 8.5±1.46 s; 20.1±0.32 vs. 9.6±0.5 g, n=5) were able to suppress remifentanil-related thermal and mechanical hyperalgesia according to behavioral test. The results highlighted the fact that CCL3 and its receptor CCR5 in DRG might contribute to remifentanil-induced hyperalgesia. Thus CCL3/CCR5 signaling may be further considered in the development of new therapeutic strategies.

Long-term hippocampal glutamate synapse and astrocyte dysfunctions underlying the altered phenotype induced by adolescent THC treatment in male rats

Cannabis use has been frequently associated with sex-dependent effects on brain and behavior. We previously demonstrated that adult female rats exposed to delta-9-tetrahydrocannabinol (THC) during adolescence develop long-term alterations in cognitive performances and emotional reactivity, whereas preliminary evidence suggests the presence of a different phenotype in male rats.To thoroughly depict the behavioral phenotype induced by adolescent THC exposure in male rats, we treated adolescent animals with increasing doses of THC twice a day (PND 35⿿45) and, at adulthood, we performed a battery of behavioral tests to measure affective- and psychotic-like symptoms as well as cognition.Poorer memory performance and psychotic-like behaviors were present after adolescent THC treatment in male rats, without alterations in the emotional component. At cellular level, the expression of the NMDA receptor subunit, GluN2B, as well as the levels of the AMPA subunits, GluA1 and GluA2, were significantly increased in hippocampal post-synaptic fractions from THC-exposed rats compared to controls. Furthermore, increases in the levels of the pre-synaptic marker, synaptophysin, and the post-synaptic marker, PSD95, were also present. Interestingly, KCl-induced [3H]D-ASP release from hippocampal synaptosomes, but not gliosomes, was significantly enhanced in THC-treated rats compared to controls. Moreover, in the same brain region, adolescent THC treatment also resulted in a persistent neuroinflammatory state, characterized by increased expression of the astrocyte marker, GFAP, increased levels of the pro-inflammatory markers, TNF-α, iNOS and COX-2, as well as a concomitant reduction of the anti-inflammatory cytokine, IL-10. Notably, none of these alterations was observed in the prefrontal cortex (PFC).Together with our previous findings in females, these data suggest that the sex-dependent detrimental effects induced by adolescent THC exposure on adult behavior may rely on its ability to trigger different region-dependent changes in glutamate synapse and glial cells. The phenotype observed in males is mainly associated with marked dysregulations in the hippocampus, whereas the prevalence of alterations in the emotional sphere in females is associated with profound changes in the PFC.

Non-cell-autonomous Neurotoxicity of α-synuclein Through Microglial Toll-like Receptor 2

Synucleinopathies are a collection of neurological diseases that are characterized by deposition of α-synuclein aggregates in neurons and glia. These diseases include Parkinson's disease (PD), dementia with Lewy bodies, and multiple system atrophy. Although it has been increasingly clear that α-synuclein is implicated in the pathogenesis of PD and other synucleinopathies, the precise mechanism underlying the disease process remains to be unraveled. The past studies on how α-synuclein exerts pathogenic actions have focused on its direct, cell-autonomous neurotoxic effects. However, recent findings suggested that there might be indirect, non-cell-autonomous pathways, perhaps through the changes in glial cells, for the pathogenic actions of this protein. Here, we present evidence that α-synuclein can cause neurodegeneration through a non-cell-autonomous manner. We show that α-synuclein can be secreted from neurons and induces inflammatory responses in microglia, which in turn secreted neurotoxic agents into the media causing neurodegeneration. The neurotoxic response of microglia was mediated by activation of toll-like receptor 2 (TLR2), a receptor for neuron-derived α-synuclein. This work suggests that TLR2 is the key molecule that mediates non-cell-autonomous neurotoxic effects of α-synuclein, hence a candidate for the therapeutic target.

Changes of excitatory and inhibitory neurotransmitters in the colon of rats underwent to the wrap partial restraint stress.

Animal models proposed to reproduce some of the human irritable bowel syndrome (IBS) symptoms are based on the hypothesis that psychosocial stressors play a pivotal role in the IBS etio-pathology. We investigated the wrap restraint stress (WRS) model with the aim to analyze the morphological changes of the entire colonic wall of these animals that showed some of the human IBS symptoms such as visceral hypersensitivity. Male Wistar rats were used and WRS was maintained for 2 h. Abdominal contractions (AC) were recorded in the colon-rectum by balloon distension. Fecal pellets were quantitated. Colonic specimens were examined by routine histology, immunohistochemistry and western blot. WRS animals were characterized by: (i) increase in AC number and fecal pellets mean weight; (ii) clusters of mononucleated cells, increase in eosinophilic granulocytes and mast cells in the mucosa; (iii) increase in CGRP-immunoreactive (IR) nerve fibers in the lamina propria; (iv) decrease in myenteric NK1r-IR and nNOS-IR neurons and in submucous nNOS-IR neurons; (v) decrease in SP-IR nerve fibers in the muscle wall; (vi) reduction in S100β-IR glia in the entire colonic wall; (vii) increase in CRF1r-IR myenteric neurons; (viii) no change in ChAT-IR neurons, smooth muscle cells and interstitial cells of Cajal. The present results support the consistency of the WRS as a potential model where part of the human IBS signs and symptoms are reproduced. The changes in glial cells and in excitatory and inhibitory neurotransmitters might represent the substrate for the dysmotility and hypersensitivity.

Time interval after ischaemic preconditioning affects neuroprotection and gliosis in the gerbil hippocampal CA1 region induced by transient cerebral ischaemia

Objectives: Ischaemic preconditioning (IPC) can increase ischaemic tolerance of the central nervous system (CNS) to a subsequent longer or lethal period of transient ischaemia. In this study, we examined neuroprotective effects of time intervals after IPC against ischaemic insult in the hippocampus.Methods: Animals were randomly assigned to six groups; sham-operated-group, ischaemia-operated-group, and three IPC (12 hours, 1- and 2-day intervals after IPC) plus ischaemia-groups (IPC-12 hour, 1 and 2-day interval-ischaemia-operated-groups). For neuroprotection, we carried out cresyl violet (CV) staining neuronal nuclei (NeuN) immunohistochemistry and Fluoro-Jade B histofluorescence staining. In addition, we examined gliosis using immunohistochemistry for GFAP (a marker for astrocytes) and Iba-1 (a marker for microglia).Results: A significant loss of neurons was observed in the stratum pyramidale (SP) of the hippocampal CA1 region (CA1) in the ischaemia-operated-group and IPC-12 hours interval-ischaemia-operated-groups. In the IPC-1 day interval-ischaemia-operated-group, CA1 pyramidal neurons were well protected from ischaemic insult; the neuroprotective effect in the IPC-2 day interval-ischaemia-operated-group was less than that in the IPC-1 day interval-ischaemia-operated-group. On the other hand, we observed changes in glial cells (astrocytes and microglia) in the CA1 of all groups. The distribution pattern of glial cells only in the IPC-1 day interval-ischaemia-operated-group was similar to that in the sham-group.Conclusion: In brief, our findings indicate that 1 day after IPC displays a mighty neuroprotection and shows an inhibition of glial activation in the CA1 induced by transient ischaemic insult.

Structural changes in gastric glial cells and delayed gastric emptying as responses to early life stress and acute adulthood stress in rats

AimEnteric glial cells (EGCs) modulate colonic motility in a maternal separation model. We aimed to investigate structural changes in gastric EGC and gastric emptying as responses to maternal separation and acute adulthood stress in rats to elucidate the pathophysiological roles of gastric EGC. Main methodsAs a chronic stress, we subjected male Wistar rats to 3h of maternal separation during postnatal days 2–14. As an acute adulthood stress (7weeks of age), we used the 8-h water-immersion method. We morphologically evaluated gastric EGCs using whole-mount longitudinal muscle-myenteric plexus preparations. We analyzed gastric emptying by the phenol red method. Key findingThe area of EGC processes that apparently overlapped with neurons increased according to stress intensity (acute stress, 10.4%; maternal separation, 10.2%; maternal separation plus acute stress, 26.6%; control, 5.0%). Ratios of morphologically changed leaf-like processes to the total processes were 8.1%, acute stress; 10.3%, maternal separation; 4.0%, control. Ratio dramatically increased in the combined stress group (20.5%, p=0.026 vs. control). The mean bulging head area of leaf-like processes in the combined stress group was greater by 6.4μm2 (control, 2.4μm2; p=0.042). Gastric emptying in the maternal separation group was gradually delayed (104.1% at 7weeks, 66.7% at 17weeks, and 48.5% at 48weeks; p<0.05, respectively). Gastric emptying in the combined stress group tended to be delayed at 17weeks (45.7% vs. 81% in controls, p=0.066). SignificanceGastric EGCs exhibited structural changes according to stress intensity, which may be associated with stress-induced dysfunction of the stomach.