Cerebral Ischemia-reperfusion Injury In Mice Research Articles

Construction of HEK293T cell line stably expressing TRPM2 channel based on PiggyBac transposition system and its application in drug screening for cerebral ischemia and other diseases

To establish a cell line stably expressing the transient receptor potential melastatin 2 (TRPM2) channel for screening TRPM2 inhibitors based on PiggyBac transposition system. A plasmid PiggyBac-human TRPM2 (pPB-hTRPM2) eukaryotic expression vector was constructed using PiggyBac transposition system. The plasmid and a helper plasmid were co-transfected into HEK293T cells to express TRPM2, which was identified by fluorescence and patch-clamp assays. The high throughput screening performance was assessed with the Z ´ factor. Calcium imaging and patch clamp techniques were employed to assess the initial activity of eleven compound molecules, confirming the inhibitory effects of the primary molecules on TRPM2. The protective effect of the screened compounds on damaged cells was validated using the oxygen-glucose deprivation/reperfusion (OGD/R) injury model and CCK-8 kit. The level of cellular reactive oxygen species (ROS) was detected by flow cytometry. The neuroprotective effects of the compounds were evaluated using a transient middle cerebral artery occlusion (tMCAO) mouse model. The HEK293T cells transfected with pPB-hTRPM2-EGFP showed high TRPM2 expression. Puromycin-resistant cells, selected through screening, exhibited robust fluorescence. Whole-cell patch results revealed that induced cells displayed classical TRPM2 current characteristics comparable to the control group, showing no significant differences (P>0.05). With a Z ´ factor of 0.5416 in calcium imaging, the model demonstrated suitability for high-throughput screening of TRPM2 inhibitors. Calcium imaging and electrophysiological experiments indicated that compound 6 significantly inhibited the TRPM2 channel. Further experiments showed that 1.0 μmol/L of compound 6 enhanced cell viability (P<0.05) and reduced the level of ROS (P<0.05) of SH-SY5Y under OGD/R injury. 0.3 and 1.0 mg/kg of compound 6 reduced the cerebral infarction volume in tMCAO mice (both P<0.05). A stable TRPM2 gene expressing cell line has been successfully established using PiggyBac gene editing in this study. TRPM2 channel inhibitors were screened through calcium imaging and patch clamp techniques, and an inhibitor compound 6 was identified. This compound can alleviate cell damage after OGD/R by reducing cellular ROS levels and has a protective effect against cerebral ischemia-reperfusion injury in mice.

MiR-96-5p alleviates cerebral ischemia-reperfusion injury in mice by inhibiting pyroptosis via downregulating caspase 1

Ischemic stroke is one of the leading causes of global mortality and disability. Nevertheless, successful treatment remains limited. In this study, we investigated the efficacy and the mechanism of miR-96-5p in protecting acute ischemic brain injury in adult mice. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in adult male C57BL/6 mice. MiR-96-5p or the negative control was administered via intracerebroventricular injection. The expression of pyroptosis-related genes and activation of various resident cells in the brain was assessed by RT-qPCR, western blot, immunohistochemistry, and immunofluorescence. Modified neurological severity score, rotarod test, cylinder test, brain water content, and cerebral infarction volume were used to evaluate the behavioral deficits and the severity of brain injury after MCAO. Flow cytometry, TUNEL staining, and Nissl staining were employed to assess the neuron damage. MiR-96-5p decreased markedly in the ischemic stroke model in vivo and in vitro. MiR-96-5p mimics suppressed the expression of caspase 1 and alleviated the apoptosis rate in OGD/R treatment N2a cells, however, the miR-96-5p inhibitor caused the opposite results. Intracerebroventricular delivery of miR-96-5p agomir significantly mitigated behavioral deficits, brain water content, and cerebral infarction volume after MCAO. In addition, treatment with miR-96-5p agomir downregulated the expression of caspase 1/cleaved caspase 1 and Gsdmd/Gsdmd-N, while alleviating the neuron damage. In summary, overexpression of miR-96-5p suppresses pyroptosis and reduces brain damage in the acute phase of ischemic stroke, providing new insight into the treatment of acute ischemic stroke.

LncRNA SNHG8 inhibits miR-494-3p expression to alleviate cerebral ischemia-reperfusion injury in mice

To explore the mechanism by which LncRNA SNHG8 regulates miR-494-3p expression to alleviate cerebral ischemia-reperfusion injury. A mouse model of cerebral ischemia-reperfusion injury was established, and TTC staining was used to determine the infarct area; ELISA was used to detect the contents of the inflammatory factors IL-1β, IL-6 and TNF-α in the brain tissue, and RT-qPCR was performed to detect the expression levels of LncRNA MALAT1 and miR-155-5p. A microglial cell model overexpressing LncRNA SNHG8 was exposed to oxygen-glucose deprivation/reoxygenation (OGD/R), and inflammatory reaction and apoptosis of the cells were detected using ELISA and flow cytometry. A luciferase reporter assay was used to detect the targeting relationship between LncRNA SNHG8 and miR-494-3p. We further constructed a microglial cell model overexpressing both LncRNA SNHG8 the miR-494-3p, and examined inflammatory reactions and apoptosis of the cells following OGD/R exposure. In the mouse model of cerebral ischemia-reperfusion injury, the contents of inflammatory factors IL-1β, IL-6 and TNF-α increased significantly in the brain tissue (P < 0.001), where LncRNA SNHG8 expression was lowered (P < 0.01) and miR-494-3p expression increased significantly (P < 0.01). In the microglial cells, overexpression of LncRNA SNHG8 significantly inhibited the inflammatory reaction and apoptosis following OGD/R exposure (P < 0.01), and overexpression of LncRNA SNHG8 strongly inhibited the expression of miR-494-3p (P < 0.01). Overexpression of miR-494-3p in microglia overexpressing SNHG8 partially promoted inflammatory reaction and cell apoptosis in response to OGD/R (P < 0.05). LncRNA SNHG8 can improve cerebral ischemia-reperfusion injury in mice by inhibiting the expression of miR-494-3p and suppressing inflammatory reactions and apoptosis of the microglia.

Downregulation of Nrp1 transcription promotes blood–brain barrier disruption following experimental cerebral ischemia–reperfusion

Disruption of the blood–brain barrier (BBB) following cerebral ischemia–reperfusion injury (CIRI) is a major factor in the pathophysiology of stroke. Endothelial cell–cell communication is essential for maintaining BBB integrity. By analyzing GSE227651 data, we found that a decrease in endothelial cell–cell communication mediated by Sema3/Nrp1 may be due to the downregulation of Nrp1 transcription, which could contribute to BBB breakdown after CIRI. We confirmed this hypothesis by using western blot analysis to show a reduction in Nrp1 protein levels in penumbra endothelial cells after CIRI in mice. We then overexpressed Nrp1 specifically in brain endothelial cells using adeno-associated virus in mice. Furthermore, Nrp1 overexpression had a protective effect on BBB integrity, as evidenced by a decrease in IgG and albumin leakage caused by CIRI in mice. Finally, we found that Nrp1 overexpression also reduced brain cell death and neurological deficits induced by cerebral ischemia–reperfusion in mice. Our findings suggest that Nrp1 downregulation may be a key factor in the breakdown of endothelial cell–cell communication and subsequent BBB disruption following CIRI. Targeting Nrp1-mediated pathways may be a promising approach for mitigating BBB damage and alleviating neurological consequences in stroke patients.

Li, P HY-021068 alleviates cerebral ischemia-reperfusion injury by inhibiting NLRP1 inflammasome and restoring autophagy function in mice

Cerebral ischemia-reperfusion injury (CIRI) is a severe pathological condition that involves oxidative stress, inflammatory response, and neuronal damage. HY-021068 belongs to a new drug of chemical class 1, which is a potential thromboxane synthase inhibitor. Our preliminary experiment found that HY-021068 has significant anti-neuroinflammatory and neuroprotective effects. However, the protective effect and mechanism of HY-021068 in CIRI remain unclear. To investigate the protective effect and mechanism of HY-021068 in CIRI mice. In mice, CIRI was induced by bilateral common carotid artery occlusion and reperfusion. Mice were treated with HY-021068 or LV-NLRP1-shRNA (lentivirus-mediated shRNA transfection to knock down NLRP1 expression). The locomotor activity, neuronal damage, pathological changes, postsynaptic density protein-95 (PSD-95) expression, NLRP1 inflammasome activation, autophagy markers, and apoptotic proteins were assessed in CIRI mice. In this study, treatment with HY-021065 and LV-NLRP1-shRNA significantly improved motor dysfunction and neuronal damage after CIRI in mice. HY-021065 and NLRP1 knockdown significantly ameliorated the pathological damage and increased PSD-95 expression in the cortex and hippocampus CA1 and CA3 regions. The further studies showed that compared with the CIRI model group, HY-021065 and NLRP1 knockdown treatment inhibited the expressions of NLRP1, ASC, caspase-1, and IL-1β, restored the expressions of p-AMPK/AMPK, Beclin1, LC3II/LC3I, p-mTOR/m-TOR and P62, and regulated the expressions of BCL-2, Caspase3, and BAX in brain tissues of CIRI mice in CIRI mice. These results suggest that HY-021068 exerts a protective role in CIRI mice by inhibiting NLRP1 inflammasome activation and regulating autophagy function and neuronal apoptosis. HY-021068 is expected to become a new therapeutic drug for CIRI.

Anti-aging Factor GRSF1 Attenuates Cerebral Ischemia-Reperfusion Injury in Mice by Inhibiting GPX4-Mediated Ferroptosis.

Abnormal accumulation of senescent cells in tissues has been shown to facilitate the onset and progression of various diseases. As an important protein involving in the regulation of cellular senescence process, researches suggested GRSF1 as a potential senolytic target to improve multiple physiological and pathological processes. However, the underlying mechanism of cellular senescence on cerebral ischemia-reperfusion injury (CIRI) has not been revealed. Here, we investigated the effect of GRSF1 on CIRI and delved into its specific mechanisms. In the present study, we established a mouse model of cerebral ischemia-reperfusion (CIR) and observed low expression of anti-aging factor GRSF1, along with greatly increased levels of senescence-related markers p16 and p21 and senescence-associated secretory phenotype TNF-α. Furthermore, we found that the expression of GPX4 was elevated parallel to GRSF1 in CIR mice with overexpression of GRSF1, oxidative stress, and iron metabolism-related proteins were inhibited. Functionally, overexpressing GRSF1 significantly ameliorated infarct volume and neurological function scores and suppressed apoptosis in CIR mice, while administration of GPX4 inhibitors reversed these beneficial phenotypes. Taken together, our results indicate cellular senescence as an important pathological mechanism to exacerbate cerebral injury during CIRI, while GRSF1 could inhibit oxidative stress-mediated ferroptosis through upregulating GPX4 to attenuate reperfusion injury, which makes senolytic treatment, especially GRSF1, a promising therapeutic target for CIRI.

TGN-020 Alleviate Inflammation and Apoptosis After Cerebral Ischemia-Reperfusion Injury in Mice Through Glymphatic and ERK1/2 Signaling Pathway.

Post-stroke acute inhibition of aquaporin 4 (AQP4) is known to exacerbate inflammation and apoptosis, yet the underlying mechanisms are not fully understood. The objective of this study was to investigate the specific mechanism of inflammation and apoptosis following cerebral ischemia-reperfusion (I/R) injury using the AQP4-specific inhibitor, N-(1,3,4-thiadiazol-2-yl) pyridine-3-carboxamide dihydrochloride (TGN-020). Ischemic stroke was induced in mice using the middle cerebral artery occlusion (MCAO) model. The C57/BL6 mice were randomly divided into three groups as follows: sham operation, I/R 48 h, and TGN-020 + I/R 48 h treatment. All mice were subjected to a series of procedures. These procedures encompassed 2,3,5-triphenyltetrazolium chloride (TTC) staining, neurological scoring, fluorescence tracing, western blotting, immunofluorescence staining, and RNA sequencing (RNA-seq). The glymphatic function in the cortex surrounding cerebral infarction was determined using tracer, glial fibrillary acid protein (GFAP), AQP4 co-staining, and beta-amyloid precursor protein (APP) staining; differential genes were detected using RNA-seq. The influence of TGN-020 on the extracellular signal-regulated kinase 1/2 (ERK) 1/2 pathway was confirmed using the ERK1/2 pathway agonists Ro 67-7467. Additionally, we examined the expression of inflammation associated with microglia and astrocytes after TGN-020 and Ro 67-7467 treatment. Compared with I/R group, TGN-020 alleviated glymphatic dysfunction by inhibiting astrocyte proliferation and reducing tracer accumulation in the peri-infarct area. RNA-seq showed that the differentially expressed genes were mainly involved in the activation of astrocytes and microglia and in the ERK1/2 pathway. Western blot and immunofluorescence further verified the expression of associated inflammation. The inflammation and cell apoptosis induced by I/R are mitigated by TGN-020. This mitigation occurs through the improvement of glymphatic function and the inhibition of the ERK1/2 pathway.

Nicotinamide Deteriorates Post-Stroke Immunodepression Following Cerebral Ischemia-Reperfusion Injury in Mice.

(1) Background: Inducing experimental stroke leads to biphasic immune responses, where the early activation of immune functions is followed by severe immunosuppression accompanied by spleen and thymus atrophy. Nicotinamide, a water-soluble B-group vitamin, is a known neuroprotectant against brain ischemia in animal models. We examined the effect of nicotinamide on the central and peripheral immune response in experimental stroke models. (2) Methods: Nicotinamide (500 mg/kg) or saline was intravenously administered to C57BL/6 mice during reperfusion after transiently occluding the middle cerebral artery or after LPS injection. On day 3, the animals were examined for behavioral performance and were then sacrificed to assess brain infarction, blood-brain barrier (BBB) integrity, and the composition of immune cells in the brain, thymus, spleen, and blood using flow cytometry. (3) Results: Nicotinamide reduced brain infarction and microglia/macrophage activation following MCAo (p < 0.05). Similarly, in LPS-injected mice, microglia/macrophage activation was decreased upon treatment with nicotinamide (p < 0.05), suggesting a direct inhibitory effect of nicotinamide on microglia/macrophage activation. Nicotinamide decreased the infiltration of neutrophils into the brain parenchyma and ameliorated Evans blue leakage (p < 0.05), suggesting that a decreased infiltration of neutrophils could, at least partially, be the result of a more integrated BBB structure following nicotinamide treatment. Our studies also revealed that administering nicotinamide led to retarded B-cell maturation in the spleen and subsequently decreased circulating B cells in the thymus and bloodstream (p < 0.05). (4) Conclusions: Cumulatively, nicotinamide decreased brain inflammation caused by ischemia-reperfusion injury, which was mediated by a direct anti-inflammatory effect of nicotinamide and an indirect protective effect on BBB integrity. Administering nicotinamide following brain ischemia resulted in a decrease in circulating B cells. This warrants attention with respect to future clinical applications.

Metabolomics profiling to characterize cerebral ischemia-reperfusion injury in mice.

Cerebral ischemia, resulting from compromised blood flow, is one of the leading causes of death worldwide with limited therapeutic options. Potential deleterious injuries resulting from reperfusion therapies remain a clinical challenge for physicians. This study aimed to explore the metabolomic alterations during ischemia-reperfusion injury by employing metabolomic analysis coupled with gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) and ultraperformance liquid chromatography quadrupole (UPLC/Q)-TOF-MS. Metabolomic data from mice subjected to middle cerebral artery occlusion (MCAO) followed by reperfusion (MCAO/R) were compared to those of the sham and MCAO groups. A total of 82 simultaneously differentially expressed metabolites were identified among each group. The top three major classifications of these differentially expressed metabolites were organic acids, lipids, and organooxygen compounds. Metabolomics pathway analysis was conducted to identify the underlying pathways implicated in MCAO/R. Based on impactor scores, the most significant pathways involved in the response to the reperfusion after cerebral ischemia were glycerophospholipid metabolism, linoleic acid metabolism, pyrimidine metabolism, and galactose metabolism. 17 of those 82 metabolites were greatly elevated in the MCAO/Reperfusion group, when compared to those in the sham and MCAO groups. Among those metabolites, glucose-6-phosphate 1, fructose-6-phosphate, cellobiose 2, o-phosphonothreonine 1, and salicin were the top five elevated metabolites in MCAO/R group, compared with the MCAO group. Glycolysis, the pentose phosphate pathway, starch and sucrose metabolism, and fructose and mannose degradation were the top four ranked pathways according to metabolite set enrichment analysis (MSEA). The present study not only advances our understanding of metabolomic changes among animals in the sham and cerebral ischemia groups with or without reperfusion via metabolomic profiling, but also paves the way to explore potential molecular mechanisms underlying metabolic alteration induced by cerebral ischemia-reperfusion.

Neuroprotective effects of betanin in mice with cerebral ischemia-reperfusion injury.

Cerebral ischemia reperfusion (IR) injury as found in stroke is a complex and heterogeneous disorder and closely related to disability and death. Today, nutraceuticals and protective therapy to increase neuronal integrity and prevent pathological complication are common. We investigated the neuroprotective effect of betanin against cerebral IR injury in mice. Forty male institute of cancer research (ICR) mice were divided into Sham-veh, IR-veh, IR-Bet50 and IR-Bet100 groups. After 2 weeks of oral administration of normal saline (vehicle; veh) or 50 mg/kg or 100 mg/kg of betanin (Bet), mice were subjected to IR induction using 30-min bilateral common carotid artery occlusion, followed by 24 h of reperfusion. Brain infarction, oxidative status, cortical and hippocampal neurons and white matter pathologies were evaluated. Results showed that IR significantly increases brain infarction, Cornus Ammonis 1 (CA1) hippocampal and corpus callosum (CC) and internal capsule (IC) white matter degeneration (P<0.05). Brain oxidative status revealed significant elevation of malondialdehyde (MDA) together with a significant decrease in catalase (CAT) activity, induced by IR (P<0.05). Pretreatment with betanin 100 mg/kg led to a significant reduction in brain infarction and MDA, CA1 hippocampus, CC and IC white matter degeneration. Betanin also led to a significant increase in CAT activity (P<0.05), with enhancing effect on reduced glutathione levels (GSH, P<0.05). The present study revealed the neuroprotective efficacy of betanin against IR injury in mice's brains, including its inhibition of lipid peroxidation, and boosting of GSH and CAT activity.

Laser speckle contrast imaging for blood flow monitoring in predicting outcomes after cerebral ischemia-reperfusion injury in mice

BackgroundIn the treatment of ischemic cerebral stroke (ICS), most conventional treatments, including carotid endarterectomy and carotid artery stenting, may cause cerebral ischemia-reperfusion injury (CIRI). For treated ICS patients, changes in cerebral blood flow are directly related to brain function. At present, computed tomography perfusion, dynamic susceptibility contrast-enhanced perfusion weighted imaging and magnetic resonance arterial spin labeling perfusion imaging are used to monitor cerebral blood flow, but they still have some limitations. Our study aimed to monitor the changes in cerebral cortical blood flow by laser speckle contrast imaging (LSCI) in CIRI model mice and to propose a new method for predicting outcomes after CIRI. C57BL/6 N mice were used to establish a mouse CIRI model based on a modified thread-occlusion method and divided into a good outcome group and a poor outcome group according to survival within 7 days. The cerebral cortical blood flow of the area supplied by the left middle cerebral artery was monitored by LSCI at baseline (before modeling), 1 h after ischemia, immediately after reperfusion and 24 h after reperfusion. Then, the brains of the mice were removed immediately and stained with hematoxylin and eosin to observe the pathological changes in brain neurons.ResultsThe cerebral cortical blood flow in the poor outcome group was obviously reduced compared with that less in the good outcome group at 24 h after reperfusion (180.8 ± 20.9 vs. 113.9 ± 6.4, p = 0.001), and at 24 h after reperfusion, the cerebral cortical blood flow was negatively correlated with the severity of brain tissue injury (p = − 0.710, p = 0.010).ConclusionsLSCI can monitor the changes in cerebral cortical blood flow during CIRI in mice and could be used as a feasible method for predicting outcomes after CIRI in mice.

TJ-M2010-5, a novel CNS drug candidate, attenuates acute cerebral ischemia-reperfusion injury through the MyD88/NF-κB and ERK pathway.

Background: Cerebral ischemia-reperfusion injury (CIRI) inevitably occurs after vascular recanalization treatment for ischemic stroke. The accompanying inflammatory cascades have a major impact on outcome and regeneration after ischemic stroke. Evidences have demonstrated that TLR/MyD88/NF-κB signaling contributes to CIRI. This study aimed to investigate the druggability of MyD88 in the central nervous system (CNS) and the neuroprotective and anti-neuroinflammatory effects of the MyD88 inhibitor TJ-M2010-5 on CIRI. Methods: A middle cerebral artery occlusion (MCAO) model was used to simulate CIRI in mice. BV-2 cells were stimulated with oxygen glucose deprivation/reoxygenation (OGD/R) or lipopolysaccharide, and SH-SY5Y cells were induced by OGD/R in vitro. Neurological deficit scores and cerebral infarction volumes were evaluated. Immunofluorescence staining was performed to measure neuronal damage and apoptosis in the brain. The anti-neuroinflammatory effect of TJ-M2010-5 was evaluated by analyzing the expression of inflammatory cytokines, activation of microglia, and infiltration of peripheral myeloid cells. The expression of proteins of the MyD88/NF-κB and ERK pathway was detected by Simple Western. The concentrations of TJ-M2010-5 in the blood and brain were analyzed by liquid chromatography-mass spectrometry. Results: The cerebral infarction volume decreased in mice treated with TJ-M2010-5, with the most prominent decrease being approximately 80% of the original infarction volume. Neuronal loss and apoptosis were reduced following TJ-M2010-5 treatment. TJ-M2010-5 inhibited the infiltration of peripheral myeloid cells and the activation of microglia. TJ-M2010-5 also downregulated the expression of inflammatory cytokines and inhibited the MyD88/NF-κB and ERK pathway. Furthermore, TJ-M2010-5 showed good blood-brain barrier permeability and no neurotoxicity. Conclusion: TJ-M2010-5 has an excellent therapeutic effect on CIRI as a novel CNS drug candidate by inhibiting excessive neuroinflammatory responses.

Fatty acid-binding proteins 3 and 5 are involved in the initiation of mitochondrial damage in ischemic neurons

We have previously shown that a fatty acid-binding protein7 (FABP7) inhibitor ameliorates cerebral ischemia-reperfusion injury in mice, suggesting an association between FABPs and ischemic neuronal injury. However, the precise role of FABPs in ischemic neuronal injury remains unclear. In this study, we investigated the role of FABPs in ischemia-reperfusion neuronal injury. FABP3, FABP5, and FABP7 were upregulated in the ischemic penumbra regions in mice. However, only FABP3 and FABP5 were expressed in injured neurons. Furthermore, FABP3 and FABP5 accumulated in the mitochondria of ischemic neurons. Overexpressing either FABP3 or FABP5 aggravated the reduced mitochondrial membrane potential and induced cell death in human neuroblastoma SH-SY5Y cells during oxidative stress. This damage was mediated by the formation of BAX-containing pores in the mitochondrial membrane. Moreover, FABP5 mediates lipid peroxidation and generates toxic by-products (i.e., 4-HNE) in SH-SY5Y cells. HY11-08 (HY08), a novel FABP3 and 5 inhibitor that does not act on FABP7, significantly reduced cerebral infarct volume and blocked FABP3/5-induced mitochondrial damage, including lipid peroxidation and BAX-related apoptotic signaling. Thus, FABP3 and FABP5 are key players in triggering mitochondrial damage in ischemic neurons. In addition, the novel FABP inhibitor, HY08, may be a potential neuroprotective treatment for ischemic stroke.

CGAS-STING pathway aggravates early cerebral ischemia-reperfusion injury in mice by activating NCOA4-mediated ferritinophagy

Stroke patients are often complicated by cerebral ischemia-reperfusion injury (CIRI) after the restoration of cerebral perfusion, and how to prevent CIRI at an early stage has received close attention. The imbalance of iron metabolism is one of the essential factors in the aggravation of CIRI, and NCOA4-mediated ferritinophagy, as a critical pathway to regulate iron metabolism, is expected to be an effective intervention target. We established a mouse model of cerebral ischemia-reperfusion (CIR) with NCOA4 silencing. We found that activation of NCOA4-mediated ferritinophagy atthe early stage of CIR mediated the onset of oxidative stress and contributed to autophagy and apoptosis, and eventually resulted in increased brain injury. This suggests that NCOA4-mediated ferritinophagy plays a vital role in early CIR and can be an effective target to prevent and treat CIRI. We next explored the upstream regulatory targets of NCOA4-mediated ferritinophagy. The previous evidence for the cGAS-STING pathway's importance during CIR and its strong relationship with autophagy attracted our attention. To investigate whether the cGAS-STING pathway regulates NCOA4-mediated ferritinophagy, we further administered a cGAS inhibitor to mice with CIR and overexpressed NCOA4. Along with the inhibition of the cGAS-STING pathway, ferritinophagy, oxidative stress, autophagy, and apoptosis were inhibited, and CIRI was ameliorated, which was attenuated by NCOA4 overexpression. In conclusion, our results suggest that activation of the cGAS-STING pathway exacerbates CIRI at the early stage of CIR, which may be achieved by mediating NCOA4-mediated ferritinophagy.

Role of hypoxia inducible factor 1α/Bcl-2/adenovirus E1B 19-kDa interacting protein 3 in alleviating effect of interleukin-4 on cerebral ischemia reperfusion injury in mice.

Cerebral ischemia reperfusion injury (CIRI) is the pathophysiological basis of various cerebrovascular diseases. The aim of this study was to explore the role of HIF-1α/BNIP3 in the alleviating effect of IL-4 on CIRI in mice. Mice were randomly divided into sham operation (Sham), ischemia reperfusion (IR), IL-4, HIF-1α inhibitor 2ME2 and IL-4+2ME2 groups. Middle cerebral artery occlusion model was established. After 24-h reperfusion, neurologic deficit score (NDS) was given. Cerebral infarction volume and brain water content were measured by 2,3,5-triphenyltetrazolium chloride staining and dry-wet weights, respectively. Apoptosis was detected by TUNEL staining. SOD, MDA and ROS levels, and HIF-1α, BNIP3, LC3II and Beclin-1 expressions were detected through colorimetry and Western blotting, respectively. Compared with IR group, NDS, cerebral infarction volume, brain water content, apoptosis rate, and MDA and ROS levels decreased, while SOD, HIF-1α, BNIP3, LC3-II and Beclin-1 levels increased in IL-4 group (P<0.05). 2ME2 and IL-4+2ME2 groups had decreased NDS, cerebral infarction volume, brain water content, apoptosis rate and MDA, ROS, HIF-1α, BNIP3, LC3-II and Beclin-1 levels, but increased SOD level compared with those of IL-4 group (P<0.05). IL-4 reduces apoptosis and oxidative stress through activating the HIF-1α/BNIP3 pathway, thereby alleviating mouse CIRI.

Mechanism of Guanxinning against cerebral ischemia-reperfusion injury in mice based on transcriptomic analysis

Guanxinning, a modern Chinese medicine preparation composed of Salviae Miltiorrhizae Radix et Rhizoma and Chuanxiong Rhizoma, has the activities of activating blood circulation, resolving blood stasis, dredging vessels, and nourishing the heart. Clinical studies have demonstrated that Guanxinning has therapeutic effect on ischemic stroke, while the specific mechanism remains to be clarified. In this study, the potential mechanism of Guanxinning against cerebral ischemia-reperfusion injury in mice was explored and then verified in vitro. The mouse model of cerebral ischemia-reperfusion injury was established with middle cerebral artery embolization(MCAO) method. The pharmacological effects of Guanxinning on the model mice were investigated based on neurological function score, cerebral infarction area, pathological morphology, neuron injury, and apoptosis. The results showed that Guanxinning lowered neurological functional score, reduced cerebral infarction area, and ameliorated the histopathological morphology, neuronal damage, and apoptosis in the model mice. RNA samples were extracted from brain tissues and subjected to RNA sequencing(RNA-seq). The differentially expressed genes(DEGs) were screened with the thresholds of ■. GO function enrichment analysis and KEGG pathway enrichment analysis were performed for the 297 common DEGs, which indicated that Guanxinning may regulate the inflammatory response, oxidative stress response, energy metabolism, and apoptosis to treat cerebral ischemia-reperfusion injury in mice. Guanxinning exerted protective effect through inhibiting inflammation and reducing oxidative stress in hypoxia/reoxygenation injured SH-SY5 Y cells. Furthermore, Western blot indicated that Guanxinning down-regulated the protein levels of p-NF-κB p65 and p-p38 MAPK and up-regulated those of PPARγ and PGC-1α. The findings suggested that Guanxinning may inhibit inflammation and reduce oxidative stress by suppressing TNF signaling pathway and activating PPAR signaling pathway, thereby exerting the therapeutic effect on cerebral ischemia-reperfusion injury in mice. This study preliminarily reveals the mechanism of Guanxinning against cerebral ischemia-reperfusion injury and provides a basis for clinical application of Guanxinning.

Chuanzhi Tongluo Capsules antagonizes cerebral ischemia-reperfusion injury in mice by inhibiting neuroinflammation and oxidative stress

Chuanzhi Tongluo Capsules(CZTL) is effective in activating blood, resolving stasis, replenishing Qi, and dredging collaterals, which has been widely used in clinical treatment of stroke(cerebral infarction) differentiated into the syndrome of wind striking meridian and collateral in the recovery stage characterized by blood stasis and Qi deficiency. However, its modern pharmacological mechanisms of action remain unclear. This study duplicated the middle cerebral artery occlusion and reperfusion(MCAO/R) model in mice using the suture-occluded method to explore the protective effect and mechanism of CZTL on ischemic stroke. The mice were divided into the sham-operation group, model group, and CZTL group. The ones in the CZTL group were gavaged with 0.3 g·kg~(-1)·d~(-1) CZTL for three successive days. One hour after the last intragastric administration, those in the model and CZTL groups were subjected to MCAO/R. After 24 h reperfusion, the effects of CZTL on neurological deficit score, cerebral infarction area, brain edema, and brain histopathology were evaluated. The levels of reactive oxygen species(ROS), malondialdehyde(MDA), interleukin-6(IL-6), interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α) and the activity of superoxide dismutase(SOD) in brain tissue homogenate were detected using corresponding assay kits. The expression of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), Toll like receptor 4(TLR4), and phosphorylated nuclear factor-κB P65 subunit(p-NF-κB P65) were assayed by Western blot. The results indicated that CZTL significantly reduced the neurological deficit score, brain edema, and infarct volume, improved the brain histopathology, inhibited the expression of ROS, MDA, IL-6, IL-1β, and TNF-α in the brain tissue, and up-regulated the activity of SOD, down-regulated the expression of pro-apoptotic protein Bax, promoted the expression of anti-apoptotic protein Bcl-2, and suppressed the expression of TLR4 and p-NF-κB P65 phosphorylation of MCAO/R mice. All these have demonstrated that CZTL has a significant protective effect against MCAO/R injury in mice, which may be related to its resistance to neuroinflammation and oxidative stress.

Metabolomic Profiling of Brain Protective Effect of Edaravone on Cerebral Ischemia-Reperfusion Injury in Mice.

Edaravone (EDA) injection has been extensively applied in clinics for treating stroke. Nevertheless, the metabolite signatures and underlying mechanisms associated with EDA remain unclear, which deserve further elucidation for improving the accurate usage of EDA. Ischemia stroke was simulated by intraluminal occlusion of the right middle cerebral artery for 1 h, followed by reperfusion for 24 h in mice. Brain infarct size, neurological deficits, and lactate dehydrogenase (LDH) levels were improved by EDA. Significantly differential metabolites were screened with untargeted metabolomics by cross-comparisons with pre- and posttreatment of EDA under cerebral ischemia/reperfusion (I/R) injury. The possibly involved pathways, such as valine, leucine, and isoleucine biosynthesis, and phenylalanine, taurine, and hypotaurine metabolisms, were enriched with differential metabolites and relevant regulatory enzymes, respectively. The network of differential metabolites was constructed for the integral exhibition of metabolic characteristics. Targeted analysis of taurine, an important metabolic marker, was performed for further validation. The level of taurine decreased in the MCAO/R group and increased in the EDA group. The inhibition of EDA on cerebral endothelial cell apoptosis was confirmed by TdT-mediated dUTP nick-end labeling (TUNEL) stain. Cysteine sulfinic acid decarboxylase (CSAD), the rate-limiting enzyme of taurine generation, significantly increased along with inhibiting endothelial cell apoptosis after treatment of EDA. Thus, CSAD, as the possible new therapeutic target of EDA, was selected and validated by Western blot and immunofluorescence. Together, this study provided the metabolite signatures and identified CSAD as an unrecognized therapeutic intervention for EDA in the treatment of ischemic stroke via inhibiting brain endothelial cell apoptosis.

Effect of metformin combined with intermittent fasting on endoplasmic reticulum stress after cerebral ischemia-reperfusion in mice

Objective: To explore the effect of metformin combined with intermittent fasting on endoplasmic reticulum stress after cerebral ischemia-reperfusion injury in mice. Methods: One hundred 10-Week-old healthy KM mice of SPF grade, weighing 25-28 g, were divided into 5 groups by the random number table method: sham group, focal cerebral ischemia group (I/R group), intermittent fasting group (IF group), metformin group (Met group), metformin+intermittent fasting group (Met+IF group). In IF group, food was provided ad libitum from 8∶00 to 16∶00 daily, but the mice were fasted for the rest of the time. In Met group, the mice underwent intraperitoneal injection of metformin (10 mg/kg). In Met+IF group, the mice received the same eating method as the IF group and the same method of metformin injection as Met Group. In Sham group, I/R group and IF group, the mice were intraperitoneally injected with equal volume of normal saline. Mice in all groups were not restricted to drinking water. Random plasma glucose and body weight changes in mice during preconditioning were monitored, and a focal cerebral ischemia-reperfusion model was established 14 days later. The cerebral infarction volume was measured after 1 hour of ischemia and 24 hours of reperfusion. The brain tissues of mice were subjected to Western blot to detect the contents of endoplasmic reticulum stress-related proteins, including glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and apoptosis proteins (Caspase-3 and Cleaved-caspase 3). Results: After different interventions, there was no significant difference in random plasma glucose changes among the four groups (all P<0.05). The blood glucose level of the mice in the Met+IF group was lower than the sham group, I/R group, IF group and Met group (all P<0.05). GRP78/β-actin in sham group, I/R group, IF group, Met group, IF+Met group were 0.48±0.05, 1.35±0.10, 0.94±0.05, 0.70±0.14, 0.41±0.37, respectively; CHOP/β-actin were 0.27±0.04, 1.03±0.03, 0.72±0.04, 0.63±0.04, 0.44±0.01, respectively; Caspase-3/β-actin were 0.51±0.04, 1.04±0.04, 0.83±0.03, 0.76±0.03, 0.63±0.05, respectively; Cleaved-Caspase-3/β-actin were 0.17±0.06, 1.01±0.20, 0.75±0.06, 0.51±0.12, 0.29±0.08, respectively, with statistically significant differences (all P<0.001). The counts of GRP78-positive cells in the hippocampus immunohistochemistry in the sham group, I/R group, IF group, Met group, and IF+Met group were 53±5, 192±11, 162±12, 140±10, 114±13, respectively, while the counts of CHOP-positive cells were 35±4, 177±12, 120±12, 100±7, 69±10, respectively, with statistically significant differences (all P<0.001). The relative volume of cerebral infarction in I/R group, IF group, Met group and IF+Met group were 0, 0.333±0.046, 0.258±0.023, 0.116±0.039, 0.111±0.039, respectively, and there were statistically significant differences (all P<0.001). Conclusion: Both Metformin and intermittent fasting can alleviate endoplasmic reticulum stress after cerebral ischemia and reperfusion in mice, and the combination of the two has a better effect.

Effect of formononetin from Trifolium pratense L. on oxidative stress, energy metabolism and inflammatory response after cerebral ischemia-reperfusion injury in mice

Cerebral ischemia-reperfusion injury (CIRI) is one of the main diseases leading to death and disability. Studying the role and mechanism of drugs in mitigating CIRI is of great significance. In the present study, the effect of formononetin from Trifolium pratense L. on oxidative stress, energy metabolism impairment and inflammatory response after cerebral ischemia-reperfusion injury (CIRI) in mice were investigated. Formononetin was extracted from Trifolium pratense L. and was purified. The mice were treated with formononetin for six days. Then, the CIRI model was established. After 24 h of reperfusion, compared with model group, in formononetin group, the neurological deficit score, cerebral water content and cerebral infarction rate were significantly decreased, the brain tissue nitric oxide and malondialdehyde levels were significantly decreased, the brain tissue superoxide dismutase level was significantly increased, the brain tissue Na+-K+-ATPase, Ca2+-Mg2+-ATPase and Ca2+-ATPase activities were significantly increased, and the brain tissue tumor necrosis factor α, interleukin 1β and interleukin 6 levels were significantly decreased. In conclusion, formononetin from Trifolium pratense L. can reduce the oxidative stress, energy metabolism impairment and inflammatory response in brain tissues, thus mitigating the CIRI in mice.