Apoptosis Of Hippocampal Neurons Research Articles

TIPE2 knockdown exacerbates isoflurane-induced postoperative cognitive impairment in mice by inducing activation of STAT3 and NF-κB signaling pathways.

Anesthetic exposure causes learning and memory impairment, the mechanisms of which remain unknown. It has been reported that tumor necrosis factor-α-inducer protein 8-like 2 (TIPE2) is a newly discovered immune negative regulator that is essential for maintaining immune homeostasis. This study aimed to examine the role of TIPE2 in isoflurane-induced postoperative cognitive decline (POCD). An AAV empty vector and AAV shTIPE2 vector for the knockdown of TIPE2 were injected into the dorsal hippocampus of mice. Mice were continuously exposed to 1.5% isoflurane followed by abdominal exploration. Behavioral tests including the open field test and fear conditioning test were performed on the third and fourth day post-operation. Apoptosis was detected by terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling staining. The kits were used to detect the activity of antioxidant enzymes. Inflammatory cytokine levels were detected by enzyme-linked immunosorbent assay. Signal transducer and activator of transcription 3 (STAT3) and nuclear factor-κB (NF-κB) signaling pathway activities were detected by western blotting. TIPE2 expression increased after isoflurane anesthesia and surgery. TIPE2 deficiency aggravated cognitive impairment in mice and further caused apoptosis and oxidative stress in hippocampal neurons. TIPE2 deficiency induced microglial activation and increased secretion of proinflammatory cytokines. In addition, TIPE2 deficiency promoted STAT3 and NF-κB signaling activation induced by isoflurane anesthesia and after surgery. TIPE2 may play a neuroprotective role in POCD by regulating STAT3 and NF-κB pathways.

Imperatorin exerts antioxidant effects in vascular dementia via the Nrf2 signaling pathway

Imperatorin, an active ingredient extracted from Angelica and Qianghuo, has anti-inflammatory, anti-oxidative stress damage, blocking calcium channels, and other properties. Our preliminary findings revealed the protective role of imperatorin in the treatment of vascular dementia, we further explored the underlying mechanisms concerning the neuroprotection function of imperatorin in vascular dementia. The cobalt chloride (COCl2)-induced chemical hypoxia and hypoglycemia of hippocampal neuronal cells was applied as in vitro vascular dementia model. Primary neuronal cells was isolated from the hippocampal tissue of SD suckling rats within 24 h of birth. Hippocampal neurons were identified by immunofluorescence staining of microtubule-associated protein 2. Silencing or overexpression of Nrf2 was conducted by transfection of corresponding plasmids in hippocampal neuronal cells. Cell viability was detected by MTT assay to determine the optimal modeling concentration of CoCl2. Mitochondrial membrane potential, intracellular reactive oxygen species and apoptosis rate was measured by flow cytometry. The expression of anti-oxidative proteins was detected by quantitative real-time PCR and western blot, including Nrf2, NQO-1 and HO-1. Nrf2 nuclear translocation was detected using laser confocal microscopy. The modeling concentration of CoCl2 was 150umol/l, and the best interventional concentration of imperatorin was 7.5umol/l. Significantly, imperatorin facilitated the nuclear localization of Nrf2, promoted the expressions of Nrf2, NQO-1, and HO-1 relative to the model-control group. Moreover, imperatorin reduced the mitochondrial membrane potential and ameliorated CoCl2-induced hypoxic apoptosis in hippocampal neurons. On the contrary, silencing Nrf2 completely abrogated the protective effects of imperatorin. Imperatorin might be an effective drug for preventing and treating vascular dementia.

Retraction notice to "The protective role of microRNA-133b in restricting hippocampal neurons apoptosis and inflammatory injury in rats with depression by suppressing CTGF" [Int. Immunopharmacol. 78 (2020) 106076

Retraction notice to "The protective role of microRNA-133b in restricting hippocampal neurons apoptosis and inflammatory injury in rats with depression by suppressing CTGF" [Int. Immunopharmacol. 78 (2020) 106076

Luteoloside Prevents Sevoflurane-induced Cognitive Dysfunction in Aged Rats via Maintaining Mitochondrial Function and Dynamics in Hippocampal Neurons.

Postoperative cognitive dysfunction (POCD) is characterized by impaired cognitive function, such as decreased learning and memory after anesthesia and surgery. This study aimed to explore the effect of luteoloside, a flavonoid extracted from natural herbs, on sevoflurane-induced cognitive dysfunction. Aged Sprague-Dawley male rats (20months old) were treated with luteoloside for 7days prior to sevoflurane exposure. After evaluation using an open field, novel object recognition, and Y-maze tests, it was determined that luteoloside effectively prevented sevoflurane-induced cognitive dysfunction. Sevoflurane exposure led to hippocampal neuron apoptosis in vivo (n=6) and in vitro (n=3), while this injury was prevented by luteoloside in a dose-dependent manner. Mechanistically, luteoloside maintained mitochondrial function and dynamics, as evidenced by the restored adenosine triphosphate (ATP) production and mitochondrial membrane potential as well as the upregulated levels of mitochondrial fission (optic atrophy protein 1 (Opa1) and mitofusin1 (Mfn1)) and downregulated mitochondrial fusion (mitochondrial fission 1 (Fisl) and dynamin-related protein 1 (Drp1)) factors. Notably, silencing Opa1 blocked the protective effect of luteoloside on hippocampal neurons and mitochondrial function. In summary, luteoloside prevented sevoflurane-induced cognitive dysfunction in aged rats, which may be achieved by regulating mitochondrial dynamics. Our study reveals the potential of luteoloside in preventing POCD in aged patients.

MiR-30b-5p targeting GRIN2A inhibits hippocampal damage in epilepsy.

GRIN2A is associated with epilepsy (EP); however, its regulatory mechanism involving upstream miRNA (miR-30b-5p) has been overlooked. In this study, we aimed to identify the regulatory mechanism of the miR-30b-5p/GRIN2A axis in EP. Hippocampal neurons isolated from mice were incubated in magnesium-free medium for 48 h to establish an in vitro EP model. An in vivo model of EP was constructed by the intraperitoneal injection of atropine into mice. Nissl staining and hematoxylin and eosin staining were used to evaluate pathological injuries in the hippocampal CA1 regions of mice. The CCK8 assay confirmed that miR-30b-5p overexpression restored the suppressed proliferative capacity of hippocampal neurons exposed to magnesium-free conditions. Caspase-3 activity assay revealed that miR-30b-5p overexpression abrogated the increased apoptosis of hippocampal neurons under magnesium-free conditions. In an in vivo model of EP, miR-30b-5p overexpression reversed pathological injuries in the hippocampal CA1 regions of mice and abrogated the increased apoptosis in the EP mouse model. Luciferase assays and western blotting confirmed that miR-30b-5p targeted GRIN2A, thereby inhibiting GRIN2A expression. Overall, miR-30b-5p can protect against cell proliferation and attenuate apoptosis in hippocampal neurons under magnesium-free conditions by targeting GRIN2A.

THE PROTECTIVE EFFECT OF C23 IN A RAT MODEL OF CARDIAC ARREST AND RESUSCITATION.

Background : Systemic inflammation acts as a contributor to neurologic deficits after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). Extracellular cold-inducible RNA-binding, protein (CIRP) has been demonstrated to be responsible in part for the inflammation through binding to toll-like receptor 4 (TLR4) after cerebral ischemia. The short peptide C23 derived from CIRP has a high affinity for TLR4, we hypothesize that C23 reduces systemic inflammation after CA/CPR by blocking the binding of CIRP to TLR4. Methods : Adult male SD rats in experimental groups were subjected to 5 min of CA followed by resuscitation. C23 peptide (8 mg/kg) or normal saline was injected intraperitoneally at the beginning of the return of spontaneous circulation (ROSC). Results : The expressions of CIRP, TNF-α, IL-6, and IL-1β in serum and brain tissues were significantly increased at 24 h after ROSC ( P < 0.05). C23 treatment could markedly decrease the expressions of TNF-α, IL-6, and IL-1β in serum ( P < 0.05). Besides, it can decrease the expressions of TLR4, TNF-α, IL-6, and IL-1β in the cortex and hippocampus and inhibit the colocalization of CIRP and TLR4 ( P < 0.05). In addition, C23 treatment can reduce the apoptosis of hippocampus neurons ( P < 0.05). Finally, the rats in the C23 group have improved survival rate and neurological prognosis ( P < 0.05). Conclusions: These findings suggest that C23 can reduce systemic inflammation and it has the potential to be developed into a possible therapy for post-CA syndrome.

Protective effect of basic helix-loop-helix family member e40 on cerebral ischemia/reperfusion injury: Inhibition of apoptosis via repressing the transcription of pleckstrin homology-like domain family A, member 1.

During ischemic stroke treatment, cerebral ischemia/reperfusion (I/R) injury results in neuronal cell death and neurological dysfunctions in brain. Previous studies indicate that basic helix-loop-helix family member e40 (BHLHE40) exerts protective effects on the pathology of neurogenic diseases. However, the protective function of BHLHE40 in I/R is unclear. This study aimed to explore the expression, role and potential mechanism of BHLHE40 after ischemia. We established models of I/R injury in rats and of oxygen-glucose deprivation/reoxygenation (OGD/R) in primary hippocampal neurons. Nissl and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was performed to detect neuronal injury and apoptosis. Immunofluorescence was used to detect BHLHE40 expression. Cell viability and cell damage measurements were conducted using Cell Counting Kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) assay. The regulation of BHLHE40 to pleckstrin homology-like domain family A, member 1 (PHLDA1) was assessed using the dual-luciferase assay and chromatin immunoprecipitation (ChIP) assay. Cerebral I/R rats exhibited severe neuronal loss and apoptosis in hippocampal cornu Ammonis 1 (CA1) region, accompanied by downregulated BHLHE40 expression at both mRNA and protein levels, indicating that BHLHE40 may regulate the apoptosis of hippocampal neurons. The function of BHLHE40 in neuronal apoptosis during cerebral I/R was further explored by establishing an OGD/R model in vitro. Low expression of BHLHE40 was also observed in neurons treated with OGD/R. The OGD/R administration inhibited cell viability and enhanced cell apoptosis in hippocampal neurons, whereas BHLHE40 overexpression reversed those changes. Mechanistically, we demonstrated that BHLHE40 could repress PHLDA1 transcription by binding to PHLDA1 promoter. The PHLDA1 is a facilitator of neuronal damage in brain I/R injury and its upregulation reversed the effects caused by BHLHE40 overexpression in vitro. The transcription factor BHLHE40 may protect against brain I/R injury through repressing cell damage via regulating PHLDA1 transcription. Thus, BHLHE40 may be a candidate gene for further study of molecular or therapeutic targets for I/R.

Neuroprotection of Emodin by Inhibition of Microglial NLRP3 Inflammasome-Mediated Pyroptosis.

Neuroinflammation triggered by chronic cerebral ischemia-induced microglial pyroptosis is a significant contributor to vascular cognitive impairment. It has been shown that emodin possesses anti-inflammatory and neuroprotective properties, however, it's potential molecular and signaling transduction pathway remains to be illuminated. This study researched the neuroprotective mechanisms of emodin focussing on emodin effects on lipopolysaccharide/adenosine triphosphate (LPS/ATP)-caused pyroptosis in BV2 cells and HT-22 hippocampal neurons. To explore the neuroprotective effect of emodin, Emodin was applied to BV2 cells, HT-22 hippocampal neurons, and BV2/HT-22 co-cultures stimulated with LPS/ATP to evaluate the cell morphology, levels of inflammatory factors, NLRP3 inflammatory inflammasome activity and focal pyroptosis-related protein expression, as same as neuronal apoptosis. Emodin alleviated LPS/ATP-induced pyroptosis of BV2 cells by preventing the activity of the NLRP3 inflammasome and the cleavage of pyroptosis executive protein Gasdermin D (GSDMD). Furthermore, levels of interleukin (IL)-18, IL-1β and tumor necrosis factor (TNF)-α were reduced, the apoptosis of HT-22 hippocampal neurons was attenuated, and cell viability was restored. Emodin can antagonize microglial neurotoxicity by inhibiting microglial pyroptosis, thereby exerting anti-inflammatory and neuroprotective effects.

Memantine/Aripiprazole Combination Alleviates Cognitive Dysfunction in Valproic Acid Rat Model of Autism: Hippocampal CREB/BDNF Signaling and Glutamate Homeostasis

SummarySignificant efforts are increasingly directed towards identifying novel therapeutic targets for autism spectrum disorder (ASD) with a rising role of aberrant glutamatergic transmission in the pathogenesis of ASD-associated cellular and behavioral deficits. This study aimed at investigating the role of chronic memantine (20 mg/kg/day) and aripiprazole (3 mg/kg/day) combination therapy in the management of prenatal sodium valproate (VPA)-induced autistic-like/cognitive deficits in male Wistar rats. Pregnant female rats received a single intraperitoneal injection of VPA (600 mg/kg) to induce autistic-like behaviors in their offspring. Prenatal VPA induced autistic-like symptoms (decreased social interaction and the appearance of stereotyped behavior) with deficits in spatial learning (in Morris water maze) and cognitive flexibility (in the attentional set-shifting task) in addition to decreased hippocampal protein levels of phosphorylated cAMP response element-binding protein (p-CREB), brain-derived neurotrophic factor (BDNF), and gene expression of glutamate transporter-1 (Glt-1) with a decline in GABA/glutamate ratio (both measured by HPLC). These were accompanied by the appearance of numerous neurofibrillary tangles (NFTs) with enhanced apoptosis in hippocampal sections. Memantine/aripiprazole combination increased the protein levels of p-CREB, BDNF, and Glt-1 gene expression with restoration of GABA/glutamate balance, attenuation of VPA-induced neurodegenerative changes and autistic-like symptoms, and improvement of cognitive performance. This study draws attention to the favorable cognitive effects of memantine/aripiprazole combination in autistic subjects which could be mediated via enhancing CREB/BDNF signaling with increased expression of astrocytic Glt-1 and restoration of GABA/glutamate balance, leading to inhibition of hippocampal NFTs formation and neuronal apoptosis.

Effect of sevoflurane anesthesia to neonatal rat hippocampus by RNA-seq

BackgroundSevoflurane is an inhalational anesthetic for the induction and maintenance of general anesthesia in pediatric surgery. However, few studies have paid attention to the multiple organ toxicity and the mechanism behind it. MethodsInhalation anesthesia neonatal rat model were realized by exposing to 3.5% sevoflurane. RNA-seq was performed to find out how inhalation anesthesia affects the lung, cerebral cortex, hippocampus, and heart. Validation of RNA-seq results by QPCR after animal model establishment. Tunel assay detects cell apoptosis in each group. CCK-8, cell apoptosis assay and western blot assay validation of the role of siRNA-Bckdhb in the action of sevoflurane on rat hippocampal neuronal cells. ResultsThere are significant differences between different groups, especially the hippocampus and cerebral cortex. Bckdhb was significantly up-regulated in the hippocampus with sevoflurane-treated. Pathway analysis revealed several abundant pathways related to DEGs, e.g., protein digestion and absorption and PI3K-Akt signaling pathway. A series of cellular and animal experiments showed that siRNA-Bckdhb can inhibit the reduction of cellular activity caused by sevoflurane. ConclusionBckdhb interference experiments indicated that sevoflurane induces hippocampal neuronal cells apoptosis by regulating Bckdhb expression. Our study provided new insights into the molecular mechanism of sevoflurane-induced brain damage in pediatrics.

Low expression of the intestinal metabolite butyric acid and the corresponding memory pattern regulate HDAC4 to promote apoptosis in rat hippocampal neurons

After intensive research on the gut-brain axis, intestinal dysbiosis is considered to be one of the important pathways of cognitive decline. Microbiota transplantation has long been thought to reverse the behavioral changes in the brain caused by colony dysregulation, but in our study, microbiota transplantation seemed to improve only behavioral brain function, and there was no reasonable explanation for the high level of hippocampal neuron apoptosis that remained. Butyric acid is one of the short-chain fatty acids of intestinal metabolites and is mainly used as an edible flavoring. It is commonly used in butter, cheese and fruit flavorings, and is a natural product of bacterial fermentation of dietary fiber and resistant starch in the colon, acting similarly to the small-molecule HDAC inhibitor TSA. The effect of butyric acid on HDAC levels in hippocampal neurons in the brain remains unclear. Therefore, this study used rats with low bacterial abundance, conditional knockout mice, microbiota transplantation, 16S rDNA amplicon sequencing, and behavioral assays to demonstrate the regulatory mechanism of short-chain fatty acids on the acetylation of hippocampal histones. The results showed that disturbance of short-chain fatty acid metabolism led to high HDAC4 expression in the hippocampus and regulated H4K8ac, H4K12ac, and H4K16ac to promote increased neuronal apoptosis. However, microbiota transplantation did not change the pattern of low butyric acid expression, resulting in maintained high HDAC4 expression in hippocampal neurons with continued neuronal apoptosis. Overall, our study shows that low levels of butyric acid in vivo can promote HDAC4 expression through the gut-brain axis pathway, leading to hippocampal neuronal apoptosis, and demonstrates that butyric acid has great potential value for neuroprotection in the brain. In this regard, we suggest that patients with chronic dysbiosis should pay attention to changes in the levels of SCFAs in their bodies, and if deficiencies occur, they should be promptly supplemented through diet and other means to avoid affecting brain health.

Erythropoietin ameliorates cognitive deficits by improving hippocampal and synaptic damage in streptozotocin-induced diabetic mice

Recent studies have shown that erythropoietin (EPO) is an effective neuroprotective and neurotrophic agent for neurological disorders, such as traumatic brain injury and Alzheimer's disease. However, the effectiveness of EPO administration against diabetic cognitive impairments has rarely been examined. In this study, we investigated the effects of EPO on streptozotocin (STZ)-induced male C57BL/6 J mice. Then, we sought to clarify the mechanisms of EPO-mediated neuroprotection in high-glucose (HG)-stimulated HT22 cells. In vivo, we found that STZ-induced diabetic mice showed impaired spatial learning and memory, which was alleviated by EPO treatment. EPO also significantly lowered elevated fasting blood glucose levels, improved pancreatic and hippocampal damage, and restored oxidative stress in the STZ-induced diabetic mice. In vitro, EPO markedly increased cell viability, restrained the expression of pro-apoptotic Bax, enhanced the expression of pro-caspase 3, anti-apoptotic Bcl-2, brain-derived neurotrophic factor (BDNF) and postsynaptic density 95 (PSD-95), and attenuated the upregulation of N-methyl-d-aspartic acid (NMDA) receptor subunits NR1, NR2A and NR2B in HG-induced HT22 cells. The protective effects of EPO was obviously abolished by treatment with an NMDA receptor agonist. Our findings revealed that EPO impedes hippocampal and synaptic damage and neuronal apoptosis by regulating BDNF and PSD-95 expression through NMDA receptors, thereby ameliorating cognitive impairments in mice with T1DM.

TaVNS Alleviates Sevoflurane-Induced Cognitive Dysfunction in Aged Rats Via Activating Basal Forebrain Cholinergic Neurons.

Postoperative cognitive dysfunction (POCD) is a common complication of central nervous system after anesthesia or surgery. Sevoflurane, an inhalation anesthetic, may inhibit cholinergic pathway that induce neuronal death and neuroinflammation, ultimately leading to POCD. Transauricular vagus nerve stimulation (taVNS) has neuroprotective effects in POCD rats, but the mechanisms related to cholinergic system have not been revealed. Sprague-Dawley rats were anesthetized with sevoflurane to construct the POCD model. The immunotoxin 192-IgG-saporin (192-sap) selectively lesioned cholinergic neurons in the basal forebrain, which is the major source of cholinergic projections to hippocampus. After lesion, rats received 5 days of taVNS treatment (30min per day) starting 24h before anesthesia. Open field test and Morris water maze were used to test the cognitive function. In this study, rats exposed to sevoflurane exhibited cognitive impairment that was attenuated by taVNS. In addition, taVNS treatment activated cholinergic system in the basal forebrain and hippocampus, and downregulated the expression of apoptosis- and necroptosis-related proteins, such as cleaved Caspase-3 and p-MLKL, in the hippocampus. Meanwhile, the activation of Iba1+ microglial by sevoflurane was reduced by taVNS. 192-sap blocked the cholinergic system activation in the basal forebrain and hippocampus and inhibited taVNS-mediated neuroprotection and anti-inflammation effects in the hippocampus. Generally, our study indicated that taVNS might alleviate sevoflurane-induced hippocampal neuronal apoptosis, necroptosis and microglial activation though activating cholinergic system in the basal forebrain.

Relationship between IL-22 and IL-22BP in diabetic cognitive dysfunction.

CD4 + T helper (Th)22 cells play a regulatory role in autoimmune diseases such as type 1 diabetes mellitus. The Th22-related cytokine interleukin (IL)-22, the expression of which is increased in diabetes mellitus (DM), can act as a neurotrophic factor to protect neurons from apoptosis. Paradoxically, neuronal apoptosis and learning and memory decline occur in DM. In this study, we investigated the relationship between IL-22 and its receptors IL-22Rα1 and IL-22 binding protein (IL-22BP, a soluble inhibitor of IL-22) in diabetic encephalopathy (DE) and the effects of IL-22 on hippocampal neurons, learning and memory. A C57BL/6 mouse model of diabetes was constructed by intraperitoneal injection of streptozotocin. The mice were randomly divided into 4 groups: the control group, diabetes group, diabetes + recombinantIL-22 (rIL-22) group and diabetes + IL-22BP group. The Morris water maze test was used to evaluate learning and memory, the expression of IL-22 was measured by ELISA, and Evans Blue staining was used to evaluate blood-brain barrier permeability. Quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to measure the mRNA expression of IL-22 and IL-22Rα1 in the hippocampus. The morphology and number of hippocampal neurons were assessed by Nissl staining, and TUNEL staining was used to detect hippocampal neuronal apoptosis. Immunofluorescence was used to analyze IL-22Rα1 expression and localization in hippocampus, and Western blotting was used to evaluate the expression of IL-22, IL-22Rα1, IL-22BP, and the apoptosis related proteins Caspase-3 and C-caspase-3. Compared with those in the control group, mice in the diabetes group showed cognitive decline; apoptosis of hippocampal neurons; increased expression of hippocampal Caspase-3, C-Caspase-3, IL-22, IL-22Rα1, and IL-22BP; and a decreased IL-22/IL-22BP ratio. Learning and memory were improved, neuronal apoptosis was attenuated, IL-22Rα1 expression and the IL-22/IL-22BP ratio were increased, and caspase-3 and C-caspase-3 expression was decreased in the rIL-22-treated group compared with the diabetes group. IL-22BP treatment aggravated diabetic cognitive dysfunction and pathological alterations in the hippocampus, decreased the IL-22/IL-22BP ratio, and increased the expression of caspase-3 and C-caspase-3 in mice with diabetes. A decrease in the IL-22/IL-22BP ratio plays an important role in diabetic cognitive dysfunction, and rIL-22 can effectively alleviate DE. Herein, we shed light on the interaction between IL-22 and IL-22BP as therapeutic targets for DM.

Studies on the mechanism of Toxoplasma gondii Chinese 1 genotype Wh6 strain causing mice abnormal cognitive behavior

BackgroundAlzheimer's disease presents an abnormal cognitive behavior. TgCtwh6 is one of the predominant T. gondii strains prevalent in China. Although T. gondii type II strain infection can cause host cognitive behavioral abnormalities, we do not know whether TgCtwh6 could also cause host cognitive behavioral changes. So, in this study, we will focus on the effect of TgCtwh6 on mouse cognitive behavior and try in vivo and in vitro to explore the underlying mechanism by which TgCtwh6 give rise to mice cognitive behavior changes at the cellular and molecular level.MethodsC57BL/6 mice were infected orally with TgCtwh6 cysts. From day 90 post-infection on, all mice were conducted through the open field test and then Morris water maze test to evaluate cognitive behavior. The morphology and number of cells in hippocampus were examined with hematoxylin-eosin (H&E) and Nissl staining; moreover, Aβ protein in hippocampus was determined with immunohistochemistry and thioflavin S plaque staining. Synaptotagmin 1, apoptosis-related proteins, BACE1 and APP proteins and genes from hippocampus were assessed by western blotting or qRT-PCR. Hippocampal neuronal cell line or mouse microglial cell line was challenged with TgCtwh6 tachyzoites and then separately cultured in a well or co-cultured in a transwell device. The target proteins and genes were analyzed by immunofluorescence staining, western blotting and qRT-PCR. In addition, mouse microglial cell line polarization state and hippocampal neuronal cell line apoptosis were estimated using flow cytometry assay.ResultsThe OFT and MWMT indicated that infected mice had cognitive behavioral impairments. The hippocampal tissue assay showed abnormal neuron morphology and a decreased number in infected mice. Moreover, pro-apoptotic proteins, as well as BACE1, APP and Aβ proteins, increased in the infected mouse hippocampus. The experiments in vitro showed that pro-apoptotic proteins and p-NF-κBp65, NF-κBp65, BACE1, APP and Aβ proteins or genes were significantly increased in the infected HT22. In addition, CD80, pro-inflammatory factors, notch, hes1 proteins and genes were enhanced in the infected BV2. Interestingly, not only the APP and pro-apoptotic proteins in HT22, but also the apoptosis rate of HT22 increased after the infected BV2 were co-cultured with the HT22 in a transwell device.ConclusionsNeuron apoptosis, Aβ deposition and neuroinflammatory response involved with microglia polarization are the molecular and cellular mechanisms by which TgCtwh6 causes mouse cognitive behavioral abnormalities.Graphical

The Mechanism of Aerobic Exercise Regulating the PI3K/Akt-mTOR Signaling Pathway Intervenes in Hippocampal Neuronal Apoptosis in Vascular Dementia Rats.

The purpose of this paper is to explore the mechanism of aerobic exercise regulating autophagy through the PI3K/Akt-mTOR signaling pathway and its participation in apoptosis, to protect the hippocampal nerves from damage in vascular dementia rats. Thirty-six healthy male SD rats were randomly divided into a sham group, a model group, and a model exercise group. A neurobehavioral assessment was used to determine the memory and exploration abilities of the rats. A TUNEL assay was used to detect hippocampal neuron apoptosis. Immunohistochemical and Western blot analyses were used to analyze LC3Ⅱ and the beclin-1 protein. An RT-PCR detected the differential expression of mRNA. The results of the neurobehavioral tests showed that the platform latency time of the rats with vascular dementia was prolonged. Aerobic exercise significantly shortens the swimming time of rats in platform latency. The TUNEL results showed that the TUNEL-positive cells of the hippocampal neurons in the model group increased; the expression of pro-apoptotic genes caspase-3 and Bax mRNA was up-regulated, and the expression of Bcl-2 mRNA was down-regulated. Aerobic exercise reduced hippocampal neuronal apoptosis, up-regulated Bcl-2 mRNA, and down-regulated caspase-3 and Bax mRNA. The LC3Ⅱ and Beclin-1 proteins, detected by immunohistochemistry and a Western blot analysis, showed that the protein expression in the hippocampi of rats with vascular dementia increased. Aerobic exercise reduced LC3Ⅱ and Beclin-1 protein expression. The results of the RT-PCR showed similar changes. Aerobic exercise could improve the learning and memory abilities of vascular dementia rats, moderately regulate the process of autophagy, reduce the TUNEL-positive cells of hippocampal neurons, repair damaged hippocampal neurons by regulating the autophagy signaling pathway PI3K/Akt-mTOR, and improve hippocampal function.

Sevoflurane Exposure of Clinical Doses in Pregnant Rats Induces Vcan Changes without Significant Neural Apoptosis in the Offspring

Background and Objectives: Sevoflurane is a commonly used inhalational anaesthetic in clinics. Prolonged exposure to sevoflurane can induce significant changes in lipid metabolism and neuronal damage in the developing brain. However, the effect of exposure of pregnant rats to clinical doses of sevoflurane remains unclear. Materials and Methods: Twenty-eight pregnant rats were randomly and equally divided into sevoflurane exposure (S) group, control (C) and a blank group at gestational day (G) 18; Rats in S group received 2% sevoflurane with 98% oxygen for 6 h in an anesthetizing chamber, while C group received 100% oxygen at an identical flow rate for 6 h in an identical chamber. Partial least squares discriminant analysis (PLS-DA), ultra performance liquid chromatography/time-of-flight mass spectrometry(UPLC/TOF-MS) and MetaboAnalyst were used to analysis acquire metabolomics profiles, and immunohistochemical changes of neuronalapoptosis in hippocampus and cortex of neonatal rats were also analyzed. Results: This study aimed to explore lipidomics and transcriptomics changes related to 2% sevoflurane exposure for 6 h in the developing brains of newborn offspring rats. Ultra-performance liquid chromatography/time-of-flight mass spectrometry (UPLC/TOF-MS) and RNA sequencing (RNA-seq) analyses were used to acquire metabolomics and transcriptomics profiles. We used RNA-seq to analyse the expression of the coding and non-coding transcripts in neural cells of the cerebral cortex. No significant differences in arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), or arterial blood gas were found between the groups. The relative standard deviation (RSD) of retention times was <1.53%, and the RSDs of peak areas ranged from 2.13% to 8.51%. Base peak chromatogram (BPC) profiles showed no differences between the groups. We evaluated the partial least square-discriminant analysis (PLS-DA) model. In negative ion mode, R2X was over 70%, R2Y was over 93%, and Q2 (cum) was over 80%. Cell apoptosis was not remarkably enhanced by TUNEL and haematoxylin and eosin (HE) staining in the sevoflurane-exposed group compared to the control group (p > 0.05). Glycerophospholipid (GP) and sphingolipid metabolism disturbances might adversely influence neurodevelopment in offspring. The expression of mRNAs (Vcan gene, related to neuronal development, function and repair) of the sevoflurane group was significantly increased in the differential genes by qRT-PCR verification. Conclusions: GP and sphingolipid metabolism homeostasis may be potential therapeutic approaches against inhalational anaesthetic-induced neurodegenerative disorders. Meanwhile, sevoflurane-induced Vcan changes indicated some lipidomic and transcriptomic changes, even if neural cell apoptosis was not significantly changed in the usual clinical dose of sevoflurane exposure.

Baicalin attenuates chronic unpredictable mild stress-induced hippocampal neuronal apoptosis through regulating SIRT1/PARP1 signaling pathway

Baicalin (BA), a flavonoid glycoside extracts from Scutellaria baicalensis Georgi, has been reported to exert antidepressant effects. Emerging evidence indicates that neuronal apoptosis plays a crucial role in the pathogenesis of depression. Poly (ADP-ribose) polymerase-1 (PARP1) is established as a key regulator of the cellular apoptosis. In the present study, we explored whether BA exerts antidepressant effects by regulating PARP1 signaling pathway and elucidated the underlying mechanisms. We found that administration of BA (30 mg/kg, 60 mg/kg) alleviated chronic unpredictable mild stress (CUMS)-induced depressive-like behaviors by increasing sucrose consumption in sucrose preference test (SPT), improving activity status in open field test (OFT) and reducing rest time in tail suspension test (TST). Hematoxylin and eosin (HE) staining and Nissl staining showed that BA ameliorated CUMS-induced neuronal damage in the hippocampus. Moreover, BA significantly upregulated anti-apoptotic protein Bcl-2, downregulated pro-apoptotic protein Bax and cleaved-caspase-3 after CUMS in hippocampal of mice. Intriguingly, western blot and immunohistochemistry (IHC) results showed that the protein level of PARP1 was significantly increased in hippocampal tissue after CUMS, which was reversed by BA treatment. In primary hippocampal neurons (PHNs), BA abrogated the neuronal apoptosis caused by PARP1 overexpression. Meanwhile, BA significantly increased the protein level of SIRT1, SIRT1 inhibitor (EX-527) treatment reversed the effect of BA on reducing the protein level of PARP1 and neuronal apoptosis in CUMS-induced mice. Overall, our results indicated that BA attenuated the CUMS-induced hippocampal neuronal apoptosis through regulating the SIRT1/PARP1 signaling pathway.

Vildagliptin restores cognitive function and mitigates hippocampal neuronal apoptosis in cisplatin-induced chemo-brain: Imperative roles of AMPK/Akt/CREB/ BDNF signaling cascades

Cisplatin (CP) is a broad-spectrum antineoplastic agent used to treat many human cancers. Nonetheless, most patients receiving CP suffer from cognitive deficits, a phenomenon termed "chemo-brain". Recently, vildagliptin (Vilda), a DPP-4 inhibitor, has demonstrated promising neuroprotective properties against various neurological diseases. Therefore, the present study aims to investigate the potential neuroprotective properties of Vilda against CP-induced neurotoxicity and elucidate the underlying molecular mechanisms. Chemo-brain was induced in Sprague-Dawley rats by i.p injection of CP at a dose of 5 mg/kg once weekly for four weeks. Vilda was administered daily at a dose (10 mg/kg; P.O) for four weeks. The results revealed that Vilda restored the cognitive function impaired by CP, as assessed by the Morris water maze, Y-maze, and passive avoidance tests.Moreover, Vilda alleviated the CP-induced neurodegeneration, as shown by toluidine blue staining, besides markedly reduced amyloid plaque deposition, as evidenced by Congo red staining. Notably, Vilda boosted cholinergic neurotransmission through the downregulation of the acetylcholinesterase enzyme. In addition, the neuroprotective mechanisms of Vilda include diminishing oxidative stress by reducing MDA levels while raising GSH levels and SOD activity, repressing neuronal apoptosis as shown by elevated Bcl-2 levels together with diminished Bax and caspase-3 expressions, inhibiting neuroinflammation as shown by decreased GFAP expression, and finally boosting hippocampal neurogenesis and survival by upregulating expressions of BDNF and PCNA. These effects were mainly mediated by activating AMPK/Akt/CREB signaling cascades. In summary, Vilda can be considered a promising candidate for guarding against CP-induced chemo-brain and neurodegeneration, thus improving the quality of life of cancer patients.

Exposure to enriched environment ameliorated chronic unpredictable mild stress-induced depression-like symptoms in rats via regulating the miR-92a-3p/kruppel-like factor 2 (KLF2) pathway

BackgroundSilencing of miR-92a-3p may be beneficial in relieving depression of chronically stressed rats. The level of kruppel-like factor 2 (KLF2) was increased in the striatum of depressed rats after ketamine treatment. Enriched environment (EE) ameliorated depression-like behaviors in rats. However, the specific mechanism of EE treatment on depression induced by chronic unpredictable mild stress (CUMS) remains unclear. MethodsAfter CUMS-induced male Sprague Dawley rats were treated under EE or/and Adeno-Associated Virus (AAV)-miR-92a-3p, depression-like behaviors, cognitive ability, dendritic spine density, as well as levels of miR-92a-3p and KLF2 were detected by the behavioral tests, morris water maze test, Golgi staining, and quantitative real-time polymerase chain reaction (qRT-PCR) as needed. The body weight of rats was also measured. Next, primary hippocampal neurons were cultivated. The targeting relationship between miR-92a-3p and KLF2 was analyzed by TargetScan v7.2 and dual-luciferase reporter assay. After hippocampal neurons were transfected with miR-92a-3p mimic or/and overexpressed KLF2 vector, the cell viability, and apoptosis, together with the levels of KLF2, brain-derived neurotrophic factor (BDNF), phosphorylated (p)-tropomysin related kinase B (p-TrkB) and TrkB were determined by MTT assay, flow cytometry, qRT-PCR, and western blot as needed. ResultsEE ameliorated CUMS-induced depression-like behaviors and cognitive ability, and elevated the neuronal dendritic spine density and KLF2 level, but reduced miR-92a-3p level in hippocampal tissues, while the above effects were reversed by AAV-miR-92a-3p. MiR-92a-3p mimic restrained cell viability, along with p-TrkB/ TrkB and BDNF levels, but promoted apoptosis in hippocampal neurons, which were reversed by overexpressed KLF2. ConclusionEE ameliorates CUMS-induced depression-like symptoms in rats via regulating the miR-92a-3p/KLF2 pathway.