Cerebral Ischemia-reperfusion Injury In Rats Research Articles

Increased TMEM166 level in patients with postoperative stroke after carotid endarterectomy

Postoperative stroke is a challenging and potentially devastating complication after elective carotid endarterectomy (CEA). We previously demonstrated that transmembrane protein 166 (TMEM166) levels were directly related to neuronal damage after cerebral ischemia-reperfusion injury in rats. In this subsequent clinical study, we aimed to evaluate the prognostic value of TMEM166 in patients suffering from post-CEA strokes. Thirty-five patients undergoing uncomplicated elective CEA and 8 patients who suffered ischemic strokes after CEA were recruited. We evaluated the protein level and expression of TMEM166 in patients diagnosed with postoperative strokes and compared it to those in patients who underwent uncomplicated elective CEA. Blood samples and carotid artery plaques were collected and analyzed. High expressions of TMEM166 were detected by immunofluorescence staining and Western Blot in carotid artery plaques of all patients who underwent CEA. Furthermore, circulating TMEM166 concentrations were statistically higher in post-CEA stroke patients than in patients allocated to the control group. Mean plasma concentrations of inflammatory markers, including interleukin 6 (IL-6) and C-reactive protein (CRP), were also elevated in patients with postoperative strokes. Therefore, based on these findings, we hypothesize that elevated TMEM166 levels, accompanied by a strong inflammatory response, serve as a useful biomarker for risk assessment of postoperative stroke following CEA.

The protective effect and mechanism of glycosides of cistanche deserticola on rats in middle cerebral artery occlusion (MCAO) model

ABSTRACT Cerebral ischemia-reperfusion injury (CIRI) occurs frequently clinically as a complication following cardiovascular resuscitation resulting in neuronal damage specifically to the hippocampal CA1 region with consequent cognitive impairment. Apoptosis and oxidative stress were proposed as major risk factors associated with CIRI development. Previously, glycosides obtained from Cistanche deserticola (CGs) were shown to play a key role in counteracting CIRI; however, the underlying mechanisms remain to be determined. This study aimed to investigate the neuroprotective effect of CGs on subsequent CIRI in rats. The model of CIRI was established for 2 hr and reperfusion for 24 hr by middle cerebral artery occlusion (MCAO) model. The MCAO rats were used to measure the antioxidant and anti-apoptotic effects of CGs on CIRI. Neurological function was evaluated by the Longa neurological function score test. 2,3,5-Triphenyltetrazolium chloride (TTC) staining was used to detect the area of cerebral infarction. Nissl staining was employed to observe neuronal morphology. TUNEL staining was used to detect neuronal apoptosis, while Western blot determined protein expression levels of factors for apoptosis-related and PI3K/AKT/Nrf2 signaling pathway. Data demonstrated that CGs treatment improved behavioral performance, brain injury, and enhanced antioxidant and anti-apoptosis in CIRI rats. In addition, CGs induced activation of PI3K/AKT/Nrf2 signaling pathway accompanied by inhibition of the expression of apoptosis-related factors. Evidence indicates that CGs amelioration of CIRI involves activation of the PI3K/AKT/Nrf2 signaling pathway associated with increased cellular viability suggesting these glycosides may be considered as an alternative compound for CIRI treatment.

Green synthesis, chemical characterization, and protective potentials of silver nanoparticles on the development of cerebrovascular diseases in rat cerebral ischemia reperfusion injury

Thrombolysis or mechanical recanalization are two methods that can be used to restore blood flow after an ischemic stroke. However, it is important to note that in certain situations, reperfusion can actually exacerbate the initial damage caused by ischemia, leading to a condition known as “cerebral reperfusion injury.” This injury involves several pathological processes, including the infiltration of leukocytes, activation of platelets and complement, postischemic hyperperfusion, and disruption of the blood–brain barrier. The main objective of research conducted globally is to create a novel therapeutic medication for stroke. In light of the nano revolution, it is imperative to merge nanoscience and medicine. Knowledge acquired from nature has paved the path for the development of biogenic technologies, facilitating the production of cutting-edge nanomaterials. We have recently conducted a study to evaluate the neuroprotective properties of a blend of Mellisa officinalis leaf extract and green-mediated silver nanoparticles on the development of cerebrovascular diseases in rat cerebral ischemia reperfusion injury. The silver nanoparticles were thoroughly examined using UV–Vis, FE-SEM, and EDX analyses to ensure comprehensive characterization. The Ag NPs were observed to have various polymorphic shapes and were found to be aggregated. Also, the particles average size was measured by ImageJ software and it is about 29.15 nm. The UV–Vis measurements showed that the spectra displayed the highest absorption at around 432 nm. The stroke occurred as a result of the occlusion of the middle cerebral artery for 1.5 h, followed by reperfusion for 2 days. Before the ischemia reperfusion, the rats received an intravenous injection of AgNPs at doses of 40, 80 and 160 µg/kg once daily for a consecutive period of 3 days. The evaluation of the cell damage index involved assessing various factors such as immunoglobulin G (IgG) extravasation into the cerebral parenchyma, lactate dehydrogenase efficacy, serum MDA level, infarct volume, and learning and memory function. The results of the study showed that pretreatment with AgNPs had a protective effect on stroke in animals. Moreover, AgNPs effectively alleviated the memory and learning impairments caused by stroke. Additionally, AgNPs significantly reduced infarct volume, IgG extravasation, serum MDA level, and lactate dehydrogenase efficacy.

Formononetin alleviates cerebral ischemia-reperfusion injury in rats by targeting the PARP-1/PARG/Iduna signaling pathway

Formononetin has been demonstrated to protect against cerebral ischemia–reperfusion injury, however its mechanism has to be further researched. This study examined the effect of formononetin on cerebral ischemia–reperfusion injury in rats using the PARP-1/PARG/Iduna signaling pathway. In male SD rats, a model of cerebral ischemia–reperfusion injury was developed. Animals were randomly assigned to one of eight groups: Sham operation, Sham operation + formononetin, MCAO, MCAO + formononetin, PARP inhibitor (PJ34) + MCAO, formononetin + PJ34 + MCAO, PARG inhibitor (Ethacridine lactate) + MCAO, and ethacridine lactate + formononetin. The neurological deficit test, TTC staining, HE staining, Nissl staining, TUNEL staining, and western blotting were utilized to assess formononetin's protective effects in MCAO rats. The data show that formononetin can effectively alleviate neurological dysfunction and pathological changes in brain tissue in rats with cerebral ischemia–reperfusion injury, reduce the area of cerebral infarction and neuronal apoptosis, decrease the protein levels of PARP-1, PARG, Caspase-3, P53, and AIF in brain tissue, and increase the protein levels of Iduna and p-AKT. As a result, we concluded that formononetin improves brain ischemia–reperfusion injury in rats by modulating the PARP-1/PARG/Iduna signaling pathway.

Multiomics profiling of the therapeutic effect of Dan-deng-tong-nao capsule on cerebral ischemia-reperfusion injury

BackgroundStroke is a complex physiological process associated with intestinal flora dysbiosis and metabolic disorders. Dan-deng-tong-nao capsule (DDTN) is a traditional Chinese medicine used clinically to treat cerebral ischemia-reperfusion injury (CIRI) for many years. However, little is known about the effects of DDTN in the treatment of CIRI from the perspective of gut microbiota and metabolites. PurposeThis study aimed to investigate the regulatory roles of DDTN in endogenous metabolism and gut microbiota in CIRI rats, thus providing a basis for clinical rational drug use and discovering natural products with potential physiological activities in DDTN for the treatment of CIRI. MethodsThe chemical composition of DDTN in vitro and in vivo was investigated using ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLCHRMS), followed by target prediction using reverse molecular docking. Secondly, a biological evaluation of DDTN ameliorating neural damage in CIRI was performed at the whole animal level. Then, an integrated omics approach based on UHPLCHRMS and 16S rRNA sequencing was proposed to reveal the anti-CIRI effect and possible mechanism of DDTN. Finally, exploring the intrinsic link between changes in metabolite profiles, changes in the intestinal flora, and targets of components to reveal DDTN for the treatment of CIRI. ResultsA total of 112 chemical components of DDTN were identified in vitro and 10 absorbed constituents in vivo. The efficacy of DDTN in the treatment of CIRI was confirmed by alleviating cerebral infarction and neurological deficits. After the DDTN intervention, 21 and 26 metabolites were significantly altered in plasma and fecal, respectively. Based on the fecal microbiome, a total of 36 genera were enriched among the different groups. Finally, the results of the network integration analysis showed that the 10 potential active ingredients of DDTN could mediate the differential expression of 24 metabolites and 6 gut microbes by targeting 25 target proteins. ConclusionThis study was the first to outline the landscapes of metabolites as well as gut microbiota regulated by DDTN in CIRI rats using multi-omics data, and comprehensively revealed the systematic relationships among ingredients, targets, metabolites, and gut microbiota, thus providing new perspectives on the mechanism of DDTN in the treatment of CIRI.

Microglia Autophagy Mediated by TMEM166 Promotes Ischemic Stroke Secondary to Carotid Artery Stenosis.

Ischemic stroke can be a serious complication of selective carotid endarterectomy (CEA) in patients with carotid artery stenosis (CAS). The underlying risk factors and mechanisms of these postoperative strokes are not completely understood. Our previous study showed that TMEM166-induced neuronal autophagy is involved in the development of secondary brain injury following cerebral ischemia-reperfusion injury in rats. This current study aimed to investigate the role of TMEM166 in ischemic stroke following CEA. In the clinical part of this study, the quantitative analysis demonstrated circulating TMEM166, interleukin 6 (IL-6), and C-reactive protein (CRP) levels were significantly elevated in patients who suffered an ischemic stroke after CEA compared to those who did not. Furthermore, non-survivors exhibited higher levels of these proteins than survivors. In the preclinical part of this study, a middle cerebral artery occlusion (MCAO) model was implemented following CAS simulation in TMEM166-/- mice. We found TMEM166 expression was positively correlated with the degree of ischemic brain injury. Ad5-TMEM166 transfection aggravated ischemic brain injury by inducing microglial autophagy activation and release of inflammatory cytokines. Accordingly, TMEM166 deficiency reduced brain inflammation and inhibited excessive microglial autophagy through the mammalian target of rapamycin (mTOR) pathway. These findings suggest that TMEM166 may play a key role in the development of ischemic injury after CEA and may serve as a biomarker for risk assessment of postoperative ischemic stroke.

Effect of Diammonium Glycyrrhizinate in Improving Focal Cerebral Ischemia-Reperfusion Injury in Rats Through Multiple Mechanisms.

Effect of Diammonium Glycyrrhizinate in Improving Focal Cerebral Ischemia-Reperfusion Injury in Rats Through Multiple Mechanisms.

Salvianolic acid A provides neuroprotective effects on cerebral ischemia-reperfusion injury in rats via PKA/CREB/c-Fos signaling pathway

BackgroundCerebral ischemia-reperfusion injury (CIRI) is a phenomenon that pathological injury of ischemic brain tissue is further aggravated after the restoration of blood supply. The complex pathological mechanism of CIRI has led to the failure of multiple neuroprotective agents in clinical studies. Salvianolic acid A (SAA) is a neuroprotective extract from Salvia miltiorrhiza Bge., with significant pharmacological activities in the treatment of brain injury. However, the neuroprotective mechanisms of SAA remain unclear. PurposeTo explore the potential protective effect of SAA on CIRI and its mechanism, and to provide experimental basis for the research of new drugs for CIRI. Study designA model of transient middle cerebral artery occlusion (tMCAO) in rats was used to simulate clinical CIRI, and the neuroprotective effect of SAA on tMCAO rats was investigated within 14 days after reperfusion. The improvement effects of SAA on cognitive impairment of tMCAO rats were investigated by behavioral tests from days 7–14. Finally, the neuroprotective mechanism of SAA was investigated on day 14. MethodsThe neuroprotective effects and mechanism of SAA were investigated by behavioral tests, HE and TUNEL staining, RNA sequence (RNA-seq) analysis and Western blot in tMCAO rats. ResultsThe brain protective effects of SAA were achieved by alleviating cerebral infarction, cerebral edema, cerebral atrophy and nerve injury in tMCAO rats. Meanwhile, SAA could effectively improve the cognitive impairment and pathological damage of hippocampal tissue, and inhibit cell apoptosis in tMCAO rats. Besides, SAA could provide neuroprotective effects by up-regulating the expression of Bcl-2, inhibiting the activation of Caspase 3, and regulating PKA/CREB/c-Fos signaling pathway. ConclusionSAA can significantly improve brain injury and cognitive impairment in CIRI rats, and this neuroprotective effect may be achieved through the anti-apoptotic effect and the regulation of PKA/CREB/c-Fos signaling pathway.

Naoxinqing tablet protects against cerebral ischemic/reperfusion injury by regulating ampkα/NAMPT/SIRT1/PGC-1α pathway

Aim of the studyNaoxinqing (NXQ) tablets are derived from persimmon leaves and are widely used in China for promoting blood circulation and removing blood stasis in China. We aimed to explore whether NXQ has the therapeutic effect on ischemic stroke and explored its possible mechanism. Materials and methodsThe cerebral artery occlusion/reperfusion (MCAO/R) surgery was used to establish the cerebral ischemic/reperfusion rat model. NXQ (60 mg/kg and 120 mg/kg) were administered orally. The TTC staining, whole brain water content, histopathology staining, immunofluorescent staining, enzyme-linked immunosorbent assay (ELISA) and Western blot analyses were performed to determine the therapeutical effect of NXQ on MCAO/R rats. ResultsThe study demonstrated that NXQ reduced the cerebral infarction volumes and neurologic deficits in MCAO/R rats. The neuroprotective effects of NXQ were accompanied by inhibited oxidative stress and inflammation. The nerve regeneration effects of NXQ were related to regulating the AMPKα/NAMPT/SIRT1/PGC-1α pathway. ConclusionIn summary, our results revealed that NXQ had a significant protective effect on cerebral ischemia-reperfusion injury in rats. This study broadens the therapeutic scope of NXQ tablets and provides new neuroprotective mechanisms of NXQ as an anti-stroke therapeutic agent.

Pharmacokinetics of 4-Hydroxybenzaldehyde in Normal and Cerebral Ischemia-Reperfusion Injury Rats Based on Microdialysis Technique.

4-Hydroxybenzaldehyde (4-HBd) isused for the treatment of headaches, dizziness, and convulsions. The objective of this study was to characterizethe pharmacokinetics of 4-HBd in cerebral ischemia-reperfusion injury (CIRI) rats by microdialysis technology with high-performance liquid chromatography with diode-array detection (HPLC-DAD) and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Microdialysis was used to collect blood, feces, and urine of normal and CIRI model rats. Pharmacokinetic parameters were determined using HPLC-DAD and 4-HBd metabolites were determined using UPLC-MS. After gavage of 4-HBd in normal and middle cerebral artery occlusion/reperfusion (MCAO/R) rats, it was widely distributed to all tissues (heart, liver, spleen, lung, kidney, and brain) in both the equilibrium and elimination phases, and the distribution pattern was basically the same; the highest concentration was found in the brain. The absolute bioavailability of 4-HBd was 5.33%; however, after intragastric administration in normal and MCAO/R rats, fecal and urinary excretion of 4-HBd accounted for 0.02% and 0.01% and for 0.01% and 0.03% of the dosage, respectively. Furthermore, 4-HBd was rapidly metabolized into 4-hydroxybenzoic acid (4-HBA) after administration in both the control and MCAO/R groups. Compared with the control, the peak time of 4-HBd plasma concentration in the MCAO/R rats decreased from 10.67 min to 8.83 min, the area under the concentration-timecurve decreased significantly, and the half-life increased from 31.81 min to 78.85 min. The rapid absorption and low absolute bioavailability of 4-HBd by gavage in rats arefollowed by rapid and wide distribution to various tissues and organs, including the brain. The prototype drug is excreted in the feces and urine in low amounts, and it is metabolized to 4-HBA in large amounts in vivo; the pathological state of the MCAO/R model mainly affects its absorption degree and metabolism rate.

Demethylnobiletin ameliorates cerebral ischemia-reperfusion injury in rats through Nrf2/HO-1 signaling pathway.

Demethylnobiletin (DN), with a variety of biological activities, is a polymethoxy-flavanone (PMF) found in citrus. In the present study, we explored the biological activities and potential mechanism of DN to improve cerebral ischemia reperfusion injury (CIRI) in rats, and identified DN as a novel neuroprotective agent for patients with ischemic brain injury. Rat CIRI models were established via middle cerebral artery occlusion (MCAO). Primary nerve cells were isolated and cultured in fetal rat cerebral cortex in vitro, and oxygen-glucose deprivation/reperfusion (OGD/R) models of primary nerve cells were induced. After intervention with DN with different concentrations in MCAO rats and OGD/R nerve cells, 2,3,5-triphenyltetrazolium chloride staining was used to quantify cerebral infarction size in CIRI rats. Modified neurological severity score was utilized to assess neurological performance. Histopathologic staining and live/dead cell-viability staining was used to observe apoptosis. Levels of glutathione (GSH), superoxide dismutase (SOD), reactive oxygen species (ROS) and malondialdehyde (MDA) in tissues and cells were detected using commercial kits. DN level in serum and cerebrospinal fluid of MCAO rats were measured by liquid chromatography tandem mass spectrometry. In addition, expression levels of proteins like Kelch like ECH associated protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nfr2) and heme oxygenase 1 (HO-1) in the Nrf2/HO-1 pathway, and apoptosis-related proteins like Cleaved caspase-3, BCL-2-associated X protein (Bax) and B-cell lymphoma-2 (Bcl-2) were determined by Western blot and immunofluorescence. DN can significantly enhance neurological function recovery by reducing cerebral infarction size and weakening neurocytes apoptosis in MCAO rats. It was further found that DN could improve oxidative stress (OS) injury of nerve cells by bringing down MDA and ROS levels and increasing SOD and GSH levels. Notably, DN exerts its pharmacological influences through entering blood-brain barrier. Mechanically, DN can reduce Keap1 expression while activate Nrf2 and HO-1 expression in neurocytes. The protective effect of DN on neurocytes have been demonstrated in both in vitro and in vivo circumstances. It deserves to be developed as a potential neuroprotective agent through regulating the Nrf2/HO-1 signaling pathway to ameliorate neurocytes impairment caused by OS.

Multi-parametric MRI assessment of melatonin regulating the polarization of microglia in rats after cerebral ischemia/reperfusion injury

ObjectivesMulti-parametric magnetic resonance imaging (MRI) can provide comprehensive and valuable information for precise diagnosis and treatment evaluation of a number of diseases. In this study, the neuroprotective effects of melatonin (Mel) on a rat model of cerebral ischemia/reperfusion injury (CIRI) were assessed by multi-parametric MRI combined with histopathological techniques for longitudinal monitoring of the lesion microenvironment. MethodsSixty Sprague Dawley (SD) rats were randomly divided into three groups: the Sham, CIRI and CIRI + Mel groups. At multiple time points after ischemia, MRI scanning was performed on a 7.0 Tesla MRI scanner. Multi-parametric MRI includes T2-weighted imaging (T2WI), diffusion weighted imaging (DWI), and chemical exchange saturation transfer (CEST)-MRI. CEST effects were calculated by the Lorentzian difference method, 3.5 ppm indicates amide protons of mobile proteins/peptide (Amide-CEST) and 2.0 ppm indicates amine protons (Guan-CEST). Multiple histopathological techniques were used to examine the histopathological changes and explore the therapeutic effects of Mel. ResultsT2WI and DWI-MRI could localize the infarct foci and areas in CIRI rats, which was further validated by staining, 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining, hematoxylin and eosin (H&E) staining, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL) staining. After Mel treatment, T2WI and DWI-MRI showed smaller infarct volume, and neurons displayed improved morphology with less apoptosis rates. Notably, Amide-CEST and Guan-CEST signal decreased as early as 2 h after CIRI (all P <0.001), reflecting the change of pH after ischemia. After Mel treatment, both Amide-CEST and Guan-CEST signal increased in ischemic cortex and striatum compared with control group (all P < 0.001). The immunofluorescence staining and western blotting analysis suggested the expression of M2 microglia increased after Mel treatment; While，after Mel treatment the inflammatory factor interleukin-1β (IL-1β) decreased compared with control CIRI rats. ConclusionsMulti-parametric MRI was shown to be an effective method to monitor the brain damage in a rat model of CIRI and assess the therapeutic effects of Mel treatment. Amide-CEST and Guan-CEST were especially sensitive to the changes in brain microenvironment during the early stage after CIRI. Furthermore, the neuroprotective effect of Mel treatment is associated with its promotion of the microglia polarized to M2 type in CIRI rats.

[Acacetin protects rats from cerebral ischemia-reperfusion injury by regulating TLR4/NLRP3 signaling pathway].

This study aims to investigate the mechanism of acacetin in protecting rats from cerebral ischemia-reperfusion injury via the Toll-like receptor 4(TLR4)/NOD-like receptor protein 3(NLRP3) signaling pathway. Wistar rats were randomized into sham, model, low-and high-dose acacetin, and nimodipine groups, with 10 rats in each group. The rat model of middle cerebral artery occlusion(MCAO) was established with the improved suture method in other groups except the sham group. The neurological deficit score and cerebral infarction volume of each group were evaluated 24 h after modeling. Enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of interleukin-1β(IL-1β), IL-6, tumor necrosis factor-α(TNF-α), malondialdehyde(MDA), supe-roxide dismutase(SOD), and glutathione(GSH). Western blot was employed to determine the expression levels of B-cell lymphonoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and TLR4/NLRP3 signaling pathway-related proteins(TLR4, p-NF-κB/NF-κB, NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1β, and cleaved IL-1β) in the rat brain tissue. Hematoxylin-eosin(HE) staining was employed to reveal the histopathological changes in the ischemic area. Compared with the sham group, the modeling of MCAO increased the neurological deficit score and cerebral infarction volume, elevated the IL-1β, IL-6, TNF-α, and MDA levels and lowered the SOD and GSH levels in the brain tissue(P&lt;0.05). Compared with the MCAO model group, low-and high-dose acacetin and nimodipine decreased the neurological deficit score and cerebral infarction volume, lowered the IL-1β, IL-6, TNF-α, and MDA levels and elevated the SOD and GSH levels in the brain tissue(P&lt;0.05). Compared with the sham group, the model group showed up-regulated protein levels of Bax, TLR4, p-NF-κB/NF-κB, NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1β, and cleaved IL-1β and down-regulated protein level of Bcl-2 in the brain tissue(P&lt;0.05). Compared with the MCAO model group, the acacetin and nimodipine groups showed down-regulated protein levels of Bax, TLR4, p-NF-κB/NF-κB, NLRP3, pro-caspase-1, cleaved caspase-1, pro-IL-1β, and cleaved IL-1β and up-regulated protein level of Bcl-2 in the brain tissue(P&lt;0.05). In conclusion, acacetin regulates the TLR4/NLRP3 signaling pathway to inhibit neuroinflammatory response and oxidative stress, thus exerting the protective effect on cerebral ischemia-reperfusion injury in rats.

A multimodal pipeline for image correction and registration of mass spectrometry imaging with microscopy

The integration of matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) and histology plays a pivotal role in advancing our understanding of complex heterogeneous tissues, which provides a comprehensive description of biological tissue with both wide molecule coverage and high lateral resolution. Herein, we proposed a novel strategy for the correction and registration of MALDI MSI data with hematoxylin & eosin (H&E) staining images. To overcome the challenges of discrepancies in spatial resolution towards the unification of the two imaging modalities, a deep learning-based interpolation algorithm for MALDI MSI data was constructed, which enables spatial coherence and the following orientation matching between images. Coupled with the affine transformation (AT) and the subsequent moving least squares algorithm, the two types of images from one rat brain tissue section were aligned automatically with high accuracy. Moreover, we demonstrated the practicality of the developed pipeline by projecting it to a rat cerebral ischemia-reperfusion injury model, which would help decipher the link between molecular metabolism and pathological interpretation towards microregion. This new approach offers the chance for other types of bioimaging to boost the field of multimodal image fusion.

Electroacupuncture at GB20 improves cognitive ability and synaptic plasticity via the CaM-CaMKII-CREB signaling pathway following cerebral ischemia-reperfusion injury in rats.

This study aimed to investigate the effects of electroacupuncture (EA) on cognitive recovery and synaptic remodeling in a rat model of middle cerebral artery occlusion (MCAO) followed by reperfusion and explore the possible mechanism. Focal cerebral ischemia was modeled in healthy adult Sprague-Dawley rats by MCAO. The MCAO rats were classified into four groups: sham, MCAO, MCAO + GB20 (receiving EA at GB20) and MCAO + NA (receiving EA at a "non-acupoint" location not corresponding to any traditional acupuncture point location about 10 mm above the iliac crest). Neurological deficit scores and behavior were assessed before and during the treatment. After intervention for 7 days, the hippocampus was dissected to analyze growth-associated protein (GAP)-43, synaptophysin (SYN) and postsynaptic density protein (PSD)-95 expression levels by Western blotting. Bioinformatic analysis and primary hippocampal neurons with calcium-voltage gated channel subunit alpha 1B (CACNA1B) gene overexpression were used to screen the target genes for EA against MCAO. Significant amelioration of neurological deficits and learning/memory were found in MCAO + GB20 rats compared with MCAO or MCAO + NA rats. Protein levels of GAP-43, SYN and PSD-95 were significantly improved in MCAO + GB20-treated rats together with an increase in the number of synapses in the hippocampal CA1 region. CACNA1B appeared to be a target gene of EA in MCAO. There were increased mRNA levels of CACNA1B, calmodulin (CaM), Ca2+/calmodulin-dependent protein kinase type II (CaMKII) and cyclic adenosine monophosphate response element binding (CREB) and increased phosphorylation of CaM, CaMKII and CREB in the hippocampal region in MCAO + GB20 versus MCAO and MCAO + NA groups. CACNA1B overexpression modulated expression of the CaM-CaMKII-CREB axis. EA treatment at GB20 may ameliorate the negative effects of MCAO on cognitive function in rats by enhancing synaptic plasticity. EA treatment at GB20 may exert this neuroprotective effect by regulating the CACNA1B-CaM-CaMKII-CREB axis.

Hyperbaric oxygen improves cerebral ischemia-reperfusion injury in rats via inhibition of ferroptosis

Background: Our previous study found that hyperbaric oxygen (HBO) attenuated cognitive impairment in mice induced by cerebral ischemia-reperfusion injury (CIRI). However, its mechanism of action is not fully understood. In this study, we aimed to establish a rat model of cerebral ischemia-reperfusion, explore the possible role of ferroptosis in the pathogenesis of CIRI, and observe the effect of HBO on ferroptosis-mediated CIRI. Methods: Sprague Dawley (SD) rats were randomly divided into control, model, Ferrostatin-1 (Fer-1), HBO and Fer-1+ HBO groups. Morris water maze, myelin basic protein (MBP) and β-tubulin immunoreactivity were assessed to evaluate the neuroprotective effects of HBO on cerebral ischemia reperfusion injury. Ferroptosis were examined to investigate the mechanism underlying the effects of HBO. Results: Our result showed that Fer-1 and HBO improved learning and memory ability in the navigation trail and probe trail of the Morris water maze and increased MBP and β-tubulin immunoreactivity of the cortex in the model rats. The levels of ferritin, malondialdehyde (MDA) and glutathione (GSH) in the serum were also reversed by Fer-1 and HBO treatment. Mitochondrial cristae dissolution and vacuolization were observed in the model group by transmission electron microscopy and these conditions were improved in the Fer-1 and HBO groups. Furthermore, Fer-1 and HBO treatment reversed Prostaglandin-Endoperoxide Synthase 2 (PTGS2), Iron Responsive Element Binding Protein 2 (IREB2), acyl-CoA synthetase long chain family member 4 (ACSL4) and Solute Carrier Family 7 Member 11 (SLC7A11) mRNA levels and Transferrin Receptor 1 (TFR1), ferritin light chain (FTL), ferritin heavy chain 1 (FTH1), glutathione peroxidase 4 (GPX4), Nuclear factor E2-related factor 2 (Nrf2), lysophosphatidylcholine acyltransferase 3 (LPCAT3), c-Jun N-terminal kinase (JNK), phosphorylated c-Jun N-terminal kinase (P-JNK) phosphorylated Extracellular signal-regulated protein kinase (P-ERK) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK) protein levels. The above changes were more pronounced in Fer-1+ HBOGroup. Discussion: The results of the present study indicated that HBO improves cerebral ischemia-reperfusion injury in rats, which may be related to inhibition of ferroptosis. This also means that ferroptosis may become a new target of HBO against CIRI.

Lithium co-administration with rutin improves post-stroke neurological outcomes via suppressing Gsk-3β activity in a rat model.

Cerebral ischemic stroke is one of the leading causes of adult disability worldwide. Reperfusion is the only therapeutic option with a lot of side effects. In the current study, we investigated the efficacy of rutin and lithium co-treatment in improving post-stroke neurological outcomes in a transient global cerebral ischemia-reperfusion injury rat model. Middle-aged male rats were subjected to transient global cerebral ischemia-reperfusion. NORT and Y-maze were used to assess the cognitive processes. Lipid peroxidation, protein carbonylation, and nitric oxide assays were performed to study oxidative stress. The excitotoxicity index was calculated by HPLC. Real time-PCR and western blotting were performed to study gene and protein expressions. The co-administration of rutin and lithium improved the overall survival, recognition memory, spatial working memory, and neurological score following cerebral ischemia-reperfusion in rats. Further, a marked decrease in malonaldehyde, protein carbonyls, and nitric oxide levels was observed following combined treatment. The mRNA expression of antioxidant (Hmox1 and Nqo1) and pro-inflammatory (Il2, Il6, and Il1β) markers were significantly attenuated in the rutin and lithium co-administrated group. The treatment inhibited the Gsk-3β and maintained a normal pool of the downstream β-catenin and Nrf2 proteins. The results revealed that co-administration of rutin and lithium had a neuroprotective potential, suggesting it to be a viable treatment to overcome post-stroke deaths and neurological complications.

IL‑4 alleviates CIRI by suppressing autophagy via the HIF‑1α/Bcl‑2/BNIP3 pathway in rats.

This paper was designed for delving into the mechanism adopted by interleukin‑4 (IL‑4) to relieve cerebral ischemia‑reperfusion injury (CIRI) in rats via suppressing autophagy. Herein, rats stochastically fell into sham operation (sham), model (RI), model + IL‑4 intervention (IL‑4), model + HIF‑1α inhibitor (2‑methoxyestradiol, 2ME2) and model + IL‑4 + 2ME2 (IL‑4 + 2ME2) groups. Next, western blotting was utilized to examine the protein expressions of microtubule‑associated protein 1 light chain 3 (LC3), p62, hypoxia‑inducible factor 1‑alpha (HIF‑1α) and Bcl‑2/adenovirus E1B 19 kDa‑interacting protein 3 (BNIP3). Relative to RI group, IL‑4 group had a significantly lower neurological impairment scale (NIS) score and an overtly lower apoptosis rate of neurons as well as a strikingly smaller cerebral infarction volume and number of autophagosomes (P<0.05). The LC3II/LC3I ratio and HIF‑1α and BNIP3 protein expressions dropped, but p62 protein expression rose pronouncedly in IL‑4 group (P<0.05). In contrast to those in RI group, the NIS score, neuronal apoptosis rate, cerebral infarction volume and autophagosome number were strikingly reduced (P<0.05). The NIS score, cerebral infarction volume, neuronal apoptosis rate, autophagosome number, LC3II/LC3I ratio and protein expressions of HIF‑1α and BNIP3 plummeted, while p62 protein expression sharply rose in IL‑4 + 2ME2 group relative to those in IL‑4 group (P<0.05). IL‑4 suppresses cell autophagy by inhibiting the HIF‑1α/BNIP3 pathway, thus relieving CIRI in rats.

[Electroacupuncture improves learning and memory impairment and enhances hippocampal synaptic plasticity through BDNF/TRKB/CREB signaling pathway in cerebral ischemia-reperfusion injury rats].

To observe the effect of electroacupuncture on brain-derived neurotrophin factor (BDNF) / tyrosine kinase receptor B (TRKB) / cyclic adenosine monophosphate response element binding protein (CREB) pathway, synaptic plasticity marker protein and synaptic ultrastructure in the hippocampus of rats with learning and memory impairment induced by cerebral ischemia reperfusion (IR), so as to explore its mechanisms underlying improvement of cognitive impairment after stroke. SD rats were randomly divided into blank, sham operation, model, and EA groups, with 12 rats in each group. The model of IR was established by occlusion of the middle cerebral artery. EA (2 Hz/10 Hz, 1-3 mA) was applied to "Shenting" (GV24) and "Baihui" (GV20) for 30 min, once daily for 14 days. The neurological function was evaluated according to the Zea Longa's score criteria. Morris water maze test was used to detect the learning and memory function of the rats. Nissl staining was used to observe the pathological morphology of the hippocampus. Transmission electron microscopy was used to observe the ultrastructure of the syna-pse in the hippocampus, the synaptic gap width and postsynaptic dense substance (PSD) thickness were measured. Immunofluorescence staining was used to observe the positive expression levels of BDNF, PSD-95 and synaptophysin (SYN) in hippocampal CA1 region. The protein expression levels of BDNF, TRKB, CREB, PSD-95, and SYN in hippocampal tissue were detected by Western blot. Compared with the sham operation group, the neurological function score and escape latency (EL) were significantly increased (P<0.01), the times of crossing the original platform were decreased (P<0.01), the number of neurons in the CA1 area of the hippocampus was reduced, with incomplete morphology, widened synaptic gaps and significantly decreased PSD thickness (P<0.01), the positive expressions of BDNF, PSD-95, SYN and the protein expression levels of BDNF, TRKB, CREB, PSD-95, SYN were significantly decreased (P<0.01) in the model group. Compared with the model group, the neurological function scores and EL on the 12th and 13th day were decreased (P<0.01, P<0.05), the times of crossing the original platform were increased (P<0.01), the morphology of hippocampal CA1 neurons improved, the synaptic gaps was decreased (P<0.01), the PSD thickness was significantly increased (P<0.01), the positive expressions of BDNF, PSD-95, SYN, and the protein expression levels of BDNF, TRKB, CREB, PSD-95, SYN were increased (P<0.05, P<0.01) in the EA group. EA can alleviate cognitive impairment in IR rats, which may be related to its function in up-regulating the proteins of BDNF/TRKB/CREB pathway, promoting the expressions of synaptic plasticity marker proteins PSD-95 and SYN, thus improving the synaptic plasticity.

[Effect of electroacupuncture pretreatment on ferroptosis in neurons of rats with cerebral ischemia-reperfusion injury].

To observe the effect of electroacupuncture（EA）preconditioning on ferroptosis in rats with cerebral ischemia-reperfusion injury （CIRI）, so as to explore the neuroprotective mechanism of EA preconditioning. Male SD rats were randomly divided into sham operation, model, EA, inhibitor and inducer groups with 20 rats in each group. The CIRI model was established by modified Zea Longa occlusion of the middle cerebral artery. Before modeling, EA treatment （2 Hz/15 Hz, 1-2 mA） was applied to "Baihui"（GV20）, "Fengfu"（GV16） and "Dazhui"（GV14） for rats of the EA group, 20 min a day for 7 consecutive days. Rats of the inhibitor group were intraperitoneally injected with ferristatin-1（25 mg/kg）at a slow and uniform rate. Rats of the inducer group were intraperitoneally injected with Erastin（100 mg/kg） after 7 days of EA preconditioning, once every 2 h for a total of 4 times. The CIRI models were prepared 2 d later after the above interventions finished by thread-occlusion. The degree of neurological impairment was evaluated by modified Zea Longa score. The percentage of infarct size was calculated by TTC staining. The ultrastructure of neurons in hippocampus was observed by transmission electron microscope. The contents of ferrous ion （Fe2+）, malondialdehyde （MDA） and glutathione （GSH） in cerebral tissue and reactive oxygen species （ROS） in serum were determined by biochemical method. The changes of mitochondrial membrane potential in rats brain tissues were detected by flow cytometry. The mRNA and protein expression levels of glutathione peroxidase 4 （GPX4）, acyl-CoA synthetase long-chain family member 4 （ACSL4）, transferrin receptor （TFRC）, 15-lipoxygenase （15-LOX） and cyclooxygenase-2 （COX-2） in the ischemic hippocampal region of CIRI rats were detected by real-time quantitative PCR and Western blot, respectively. Compared with the sham operation group, the neurological impairment score, the percentage of cerebral infarction area, the contents of MDA and Fe2+ in cerebral tissue as well as ROS in serum, the protein and mRNA expression levels of ACSL4, TFRC, 15-LOX, COX-2 in hippocampal tissue were increased （P<0.01）, while the content of GSH in cerebral tissue, the protein and mRNA expression levels of GPX4 in hippocampal tissue were decreased （P<0.01）, and mitochondria in brain tissue were significantly damaged （P<0.01） in the model group. Compared with the model group, the above indexes were all reversed （P<0.05, P<0.01） in the EA group and inhibitor group. Compared with the EA group, the neurological impairment score, the percentage of cerebral infarction area, the contents of MDA and Fe2+ in cerebral tissue as well as ROS in serum, the protein and mRNA expression le-vels of ACSL4, TFRC, 15-LOX, COX-2 in hippocampal tissue were increased （P<0.05, P<0.01）, while the content of GSH in cerebral tissue, the protein and mRNA expression levels of GPX4 in hippocampal tissue were decreased （P<0.01, P<0.05）, and mitochondria in brain tissue were significantly damaged （P<0.05） in the inducer group. EA preconditioning has neuroprotective effect on CIRI rats, which may be related to inhibiting ACSL4/TFRC/15-LOX/COX-2 expression and increasing GSH/GPX4 expression.