Upregulation of vascular endothelial growth factor receptor-1 contributes to sevoflurane preconditioning-mediated cardioprotection

Heart rate variability as a predictor of intraoperative autonomic nervous system homeostasis

The aim of the proof-of-concept study is to investigate the level of concordance between the heart rate variability (HRV), the EEG-based Narcotrend Index as a surrogate marker for the depth of hypnosis, and the minimal alveolar concentration (MAC) of the inhalation anesthetic sevoflurane across the entire course of a surgical procedure. This non-blinded cross-sectional study recorded intraoperative HRV, Narcotrend Index, and MAC in 31 male patients during radical prostatectomy using the Da-Vinci robotic-assisted surgical system at Mannheim University Medical Center. The degree of concordance was calculated using repeated measures correlation with the R package (rmcorr) and presented using the rmcorr coefficient (rrm). The Narcotrend Index correlates significantly across all measures with the time-dependent parameter of HRV, the standard deviation of the means of RR intervals (SDNN) (rrm = 0.2; p < 0.001), the frequency-dependent parameters low frequency (LF) (rrm = 0.09; p = 0.04) and the low frequency/high frequency ratio (LF/HF ratio) (rrm = 0.11; p = 0.002). MAC correlated significantly negatively with the time-dependent parameter of heart rate variability, SDNN (rrm = -0.28; p < 0.001), the frequency-dependent parameter LF (rrm = -0.06; p < 0.001) and the LF/HF ratio (rrm = -0.18; p < 0.001) and the Narcotrend Index (rrm = -0.49; p < 0.001) across all measures. HRV mirrors the trend of the Narcotrend Index used to monitor depth of hypnosis and the inhibitory influence of the anesthetic sevoflurane on the autonomic nervous system. Therefore, HRV can provide essential information about the homeostasis of the autonomic nervous system during general anesthesia. DRKS00024696, March 9th, 2021.

Sevoflurane postconditioning attenuates cardiomyocytes hypoxia/reoxygenation injury via PI3K/AKT pathway mediated HIF-1α to regulate the mitochondrial dynamic balance

BACKGROUND

Myocardial ischemia-reperfusion injury (I/RI) is a major cause of perioperative cardiac-related adverse events and death. Studies have shown that sevoflurane postconditioning (SpostC), which attenuates I/R injury and exerts cardioprotective effects, regulates mitochondrial dynamic balance via HIF-1α, but the exact mechanism is unknown. This study investigates whether the PI3K/AKT pathway in SpostC regulates mitochondrial dynamic balance by mediating HIF-1α, thereby exerting myocardial protective effects.

METHODS

The H9C2 cardiomyocytes were cultured to establish the hypoxia-reoxygenation (H/R) model and randomly divided into 4 groups: Control group, H/R group, sevoflurane postconditioning (H/R + SpostC) group and PI3K/AKT blocker (H/R + SpostC + LY) group. Cell survival rate was determined by CCK-8; Apoptosis rate was determined by flow cytometry; mitochondrial membrane potential was evaluated by Mito Tracker™ Red; mRNA expression levels of AKT, HIF-1α, Opa1and Drp1 were detected by quantitative real-time polymerase chain reaction (qRT-PCR); Western Blot assay was used to detect the protein expression levels of AKT, phosphorylated AKT (p-AKT), HIF-1α, Opa1 and Drp1.

RESULTS

Compared with the H/R group, the survival rate of cardiomyocytes in the H/R + SpostC group increased, the apoptosis rate decreased and the mitochondrial membrane potential increased. qRT-PCR showed that the mRNA expression of HIF-1α and Opa1 were higher in the H/R + SpostC group compared with the H/R group, whereas the transcription level of Drp1 was lower in the H/R + SpostC group. In the H/R + SpostC + LY group, the mRNA expression of HIF-1α was lower than the H/R + SpostC group. There was no difference in the expression of Opa1 mRNA between the H/R group and the H/R + SpostC + LY group. WB assay results showed that compared with the H/R group, the protein expression levels of HIF-1α, Opa1, P-AKT were increased and Drp1 protein expression levels were decreased in the H/R + SpostC group. HIF-1α, P-AKT protein expression levels were decreased in the H/R + SpostC + LY group compared to the H/R + SpostC group.

CONCLUSION

SpostC mediates HIF-1α-regulated mitochondrial fission and fusion-related protein expression to maintain mitochondrial dynamic balance by activating the PI3K/AKT pathway and increasing AKT phosphorylation, thereby attenuating myocardial I/R injury.

The SNHG10-miR-495-3p-PTEN axis is involved in sevoflurane-mediated protective effects in cardiomyocytes against hypoxia/reoxygenation injury

Myocardial infarction (MI) has been considered a leading cause of death worldwide. Relieving ischemia-reperfusion myocardial damage is one of the major roles in treating MI. Sevoflurane postconditioning provides myocardial protection, and this study probes the mechanism of sevoflurane-mediated protective effects. A hypoxia/reoxygenation (H/R) model was constructed in cardiomyocytes, which were pretreated with 2.4% sevoflurane. Alterations in SNHG10, miR-495-3p, and PTEN levels were determined, and gain- or loss-of functional assays were conducted to confirm the role of the SNHG10/miR-495-3p axis, which is potentially regulated by sevoflurane. Cell viability, oxidative stress, and inflammatory reactions were all evaluated. The results indicated that sevoflurane post-conditioning attenuated H/R-induced cardiomyocyte damage and reduced the SHNH10 level. SNHG10 overexpression reversed sevoflurane-mediated protective effects on cardiomyocytes. Moreover, SNHG10 targeted miR-495-3p and restrained its expression, while miR-495-3p targeted PTEN, suppressed PTEN levels, and promoted HIF-1α expression. miR-495-3p overexpression decreased SNHG10-mediated myocardial injury and enhanced HIF-1α levels. However, no additional protection was found when sevoflurane was administered to H/R-exposed cardiomyocytes following treatment with the HIF-1α inhibitor LW6. Overall, sevoflurane protects cardiomyocytes from H/R by modulating the SNHG10-miR-495-3p-PTEN-HIF-1α axis.

Preservation solution Custodiol containing human alpha-1-antitrypsin improves graft recovery after prolonged cold ischemic storage in a rat model of heart transplantation

Introduction

The shortage of available donor hearts and the risk of ischemia/reperfusion injury restrict heart transplantation (HTX). Alpha-1-antitrypsin (AAT), a well-characterized inhibitor of neutrophil serine protease, is used in augmentation therapy to treat emphysema due to severe AAT deficiency. Evidence demonstrates its additional anti-inflammatory and tissue-protective effects. We hypothesized that adding human AAT in a preservation solution reduces graft dysfunction in a rat model of HTX following extended cold ischemic storage.

Methods

The hearts from isogenic Lewis donor rats were explanted, stored for either 1h or 5h in cold Custodiol supplemented with either vehicle (1h ischemia, n=7 or 5h ischemia, n=7 groups) or 1 mg/ml AAT (1h ischemia+AAT, n=7 or 5h ischemia+AAT, n=9 groups) before heterotopic HTX. Left-ventricular (LV) graft function was evaluated in vivo 1.5h after HTX. Immunohistochemical detection of myeloperoxydase (MPO) was performed in myocardial tissue and expression of 88 gene quantified with PCR was analyzed both statistical and with machine-learning methods.

Results

After HTX, LV systolic function (dP/dt_max 1h ischemia+AAT 4197 ± 256 vs 1h ischemia 3123 ± 110; 5h ischemia+AAT 2858 ± 154 vs 5h ischemia 1843 ± 104mmHg/s, p<0.05) and diastolic function (dP/dt_min 5h ischemia+AAT 1516 ± 68 vs 5h ischemia 1095 ± 67mmHg/s, p<0.05) at an intraventricular volume of 90µl were improved in the AAT groups compared with the corresponding vehicle groups. In addition, the rate pressure product (1h ischemia+AAT 53 ± 4 vs 1h ischemia 26 ± 1; 5h ischemia+AAT 37 ± 3 vs 5h ischemia 21 ± 1mmHg*beats/min at an intraventricular volume of 90µl; p<0.05) was increased in the AAT groups compared with the corresponding vehicle groups. Moreover, the 5h ischemia+AAT hearts exhibited a significant reduction in MPO-positive cell infiltration in comparison to the 5h ischemia group. Our computational analysis shows that ischemia+AAT network displays higher homogeneity, more positive and fewer negative gene correlations than the ischemia+placebo network.

Discussion

We provided experimental evidence that AAT protects cardiac grafts from prolonged cold ischemia during HTX in rats.

Pharmacological Cardioprotection against Ischemia Reperfusion Injury-The Search for a Clinical Effective Therapy

Pharmacological conditioning aims to protect the heart from myocardial ischemia-reperfusion injury (IRI). Despite extensive research in this area, today, a significant gap remains between experimental findings and clinical practice. This review provides an update on recent developments in pharmacological conditioning in the experimental setting and summarizes the clinical evidence of these cardioprotective strategies in the perioperative setting. We start describing the crucial cellular processes during ischemia and reperfusion that drive acute IRI through changes in critical compounds (∆G_ATP, Na⁺, Ca²⁺, pH, glycogen, succinate, glucose-6-phosphate, mitoHKII, acylcarnitines, BH₄, and NAD⁺). These compounds all precipitate common end-effector mechanisms of IRI, such as reactive oxygen species (ROS) generation, Ca²⁺ overload, and mitochondrial permeability transition pore opening (mPTP). We further discuss novel promising interventions targeting these processes, with emphasis on cardiomyocytes and the endothelium. The limited translatability from basic research to clinical practice is likely due to the lack of comorbidities, comedications, and peri-operative treatments in preclinical animal models, employing only monotherapy/monointervention, and the use of no-flow (always in preclinical models) versus low-flow ischemia (often in humans). Future research should focus on improved matching between preclinical models and clinical reality, and on aligning multitarget therapy with optimized dosing and timing towards the human condition.

Fluoxetine alleviates postoperative cognitive dysfunction by attenuating TLR4/MyD88/NF-κB signaling pathway activation in aged mice

OBJECTIVE AND DESIGN

Postoperative cognitive dysfunction (POCD) is a common complication following surgery among elderly patients. Emerging evidence demonstrates that neuroinflammation plays a pivotal role in the pathogenesis of POCD. This study tested the hypothesis that fluoxetine can protect against POCD by suppressing hippocampal neuroinflammation through attenuating TLR4/MyD88/NF-κB signaling pathway activation.

SUBJECTS

Aged C57BL/6 J male mice (18 months old) were studied.

TREATMENT

Aged mice were intraperitoneally injected with fluoxetine (10 mg/kg) or saline for seven days before splenectomy. In addition, aged mice received an intracerebroventricular injection of a TLR4 agonist or saline seven days before splenectomy in the rescue experiment.

METHODS

On postoperative days 1, 3, and 7, we assessed hippocampus-dependent memory, microglial activation status, proinflammatory cytokine levels, protein levels related to the TLR4/MyD88/NF-κB signaling pathway, and hippocampal neural apoptosis in our aged mouse model.

RESULTS

Splenectomy induced a decline in spatial cognition, paralleled by parameters indicating exacerbation of hippocampal neuroinflammation. Fluoxetine pretreatment partially restored the deteriorated cognitive function, downregulated proinflammatory cytokine levels, restrained microglial activation, alleviated neural apoptosis, and suppressed the increase in TLR4, MyD88, and p-NF-κB p65 in microglia. Intracerebroventricular injection of LPS (1 μg, 0.5 μg/μL) before surgery weakened the effect of fluoxetine.

CONCLUSION

Fluoxetine pretreatment suppressed hippocampal neuroinflammation and mitigated POCD by inhibiting microglial TLR4/MyD88/NF-κB pathway activation in aged mice.

Myocardial Protection and Current Cancer Therapy: Two Opposite Targets with Inevitable Cost

Myocardial protection against ischemia/reperfusion injury (IRI) is mediated by various ligands, activating different cellular signaling cascades. These include classical cytosolic mediators such as cyclic-GMP (c-GMP), various kinases such as Phosphatydilinositol-3- (PI3K), Protein Kinase B (Akt), Mitogen-Activated-Protein- (MAPK) and AMP-activated (AMPK) kinases, transcription factors such as signal transducer and activator of transcription 3 (STAT3) and bioactive molecules such as vascular endothelial growth factor (VEGF). Most of the aforementioned signaling molecules constitute targets of anticancer therapy; as they are also involved in carcinogenesis, most of the current anti-neoplastic drugs lead to concomitant weakening or even complete abrogation of myocardial cell tolerance to ischemic or oxidative stress. Furthermore, many anti-neoplastic drugs may directly induce cardiotoxicity via their pharmacological effects, or indirectly via their cardiovascular side effects. The combination of direct drug cardiotoxicity, indirect cardiovascular side effects and neutralization of the cardioprotective defense mechanisms of the heart by prolonged cancer treatment may induce long-term ventricular dysfunction, or even clinically manifested heart failure. We present a narrative review of three therapeutic interventions, namely VEGF, proteasome and Immune Checkpoint inhibitors, having opposing effects on the same intracellular signal cascades thereby affecting the heart. Moreover, we herein comment on the current guidelines for managing cardiotoxicity in the clinical setting and on the role of cardiovascular confounders in cardiotoxicity.

A pharmacokinetic-pharmacodynamic study to elucidate the cardiovascular protective constituents in Danhong Injection

Danhong Injection (DHI) is one of the most popular Chinese medicine formulations to treat cardiovascular diseases. However, the effective components of DHI have not been well addressed. In the present study, a pharmacokinetics-pharmacodynamics (PK-PD) approach was employed to elucidate the effective compounds of DHI for the first time. Firstly, the cardiovascular protective effect of DHI was demonstrated on an adrenaline-induced acute blood stasis rat model by echocardiography and histopathology. Secondly, the levels of four blood stasis-related cytokines in plasma were examined by ELISA. Thirdly, the plasma concentrations of 10 compounds in DHI were determined using UHPLC-Q-Orbitrap-MS. Finally, PK-PD profiles were established to describe the relationship between compound concentrations and cytokine levels in plasma at 0-12 h following DHI administration. The results showed that DHI attenuated cardiovascular injury and regulated IL-2, cTnT, VEGF, and VEGFR-1. Except for the endogenous metabolites cytidine and uridine, danshensu, rosmarinic acid, and salvianolic acid B exhibited the highest plasma exposure. PK-PD correlation analysis indicated that concentrations of salvianolic acid A, caffeic acid, and ferulic acid were negatively correlated with the level of cTnT, while the concentration of salvianolic acid A was negatively correlated with the level of IL-2. These compounds may contribute to the cardiovascular protective effect of DHI.

Molecular Mechanism of Sevoflurane Preconditioning Based on Whole-transcriptome Sequencing of Lipopolysaccharide-induced Cardiac Dysfunction in Mice

ABSTRACT

Sevoflurane, a widely used inhalation anesthetic, has been shown to be cardioprotective in individuals with sepsis and myocardial dysfunction. However, the exact mechanism has not been completely explained. In this study, we performed whole-transcriptome profile analysis in the myocardium of lipopolysaccharide-induced septic mice after sevoflurane pretreatment. RNA transcriptome sequencing showed that 97 protein coding RNAs (mRNAs), 64 long noncoding RNAs (lncRNAs), and 27 microRNAs (miRNAs) were differentially expressed between the lipopolysaccharide and S_L groups. Functional enrichment analysis revealed that target genes for the differentially expressed mRNAs between the 2 groups participated in protein processing in the endoplasmic reticulum, antigen processing and presentation, and the mitogen-activated protein kinase signaling pathway. The bioinformatics study of differentially expressed mRNAs revealed that 13 key genes including Hsph1, Otud1, Manf, Gbp2b, Stip1, Gbp3, Hspa1b, Aff3, Med12, Kdm4a, Gatad1, Cdkn1a, and Ppp1r16b are related to the heart or inflammation. Furthermore, the competing endogenous RNA network revealed that 3 of the 13 key genes established the lncRNA-miRNA-mRNA network (ENSMUST00000192774 --- mmu-miR-7a-5p --- Hspa1b, TCONS_00188587 --- mmu-miR-204-3p --- Aff3 and ENSMUST00000138273 --- mmu-miR-1954 --- Ppp1r16b) may be associated with cardioprotection in septic mice. In general, the findings identified 11 potential essential genes (Hsph1, Otud1, Manf, Gbp2b, Stip1, Gbp3, Hspa1b, Aff3, Med12, Kdm4a, Gatad1, Cdkn1a, and Ppp1r16b) and mitogen-activated protein kinase signaling pathway involved in sevoflurane-induced cardioprotection in septic mice. In particular, sevoflurane may prevent myocardial injury by regulating the lncRNA-miRNA-mRNA network, including (ENSMUST00000192774-mmu-miR-7a-5p-Hspa1b, TCONS_00188587-mmu-miR-204-3p-Aff3, and ENSMUST00000138273-mmu-miR-1954-Ppp1r16b networks), which may be a novel mechanism of sevoflurane-induced cardioprotection.

Sevoflurane prevents pulmonary vascular remodeling and right ventricular dysfunction in pulmonary arterial hypertension in rats

BACKGROUND

The cardioprotective properties of sevoflurane have been reported in studies of the left ventricle. However, whether this volatile anesthetic would also be beneficial for pulmonary vascular remodeling and associated right ventricular hypertrophy (RVH) remained to be explored. Here, we investigated the potential benefit of sevoflurane to right heart function in experimental pulmonary arterial hypertension (PAH).

METHODS

Adult Wistar rats received one dose peritoneal injection of monocrotaline (MCT, 60 mg/kg) or the equal volume of normal saline. Two weeks later, rats were treated with sevoflurane or sham exposure. PAH status and cardiac function were assessed by echocardiography weekly, and the body weight (BW) was monitored every week. After 6 weeks of exercise, Fulton's index calculation, histological observation, IL-6 and TNF-α immunohistochemical analyses, evaluation of MDA, SOD and GSH-Px levels and NF-κB and MAPK active determination were performed in lung and RV tissue samples.

RESULTS

MCT induced pulmonary vascular remodeling, RVH, increased Fulton's index (P<0.01), and right ventricular failure (RVF) in rats. Animals inhaled sevoflurane had an increased cardiac output (P<0.05) and lower incidence of RVF (P<0.05). Also, these animals had a reduced RVEDD, RVWTd and PAID (P<0.05), increased PV (P<0.05), reduced wall thickness and vascular wall area of pulmonary small vascular (vascular external diameter 50-150 um) (P<0.01), reduced RV fibrosis, and increased RV cardiomyocyte area (P<0.01). Furthermore, sevoflurane reduced IL-6 and TNF-α expression in lungs and heart (P<0.01), decreased level of MDA (P<0.01) and increased activity of SOD and GSH-Px (P<0.01). In addition, it decreased the activities of NF-κB and MAPK pathways (P<0.01).

CONCLUSION

Sevoflurane reduces pulmonary vascular remodeling and RVH in PAH induced by MCT in rats. This effect is likely due to down-regulation of inflammatory factors IL-6 and TNF-α, reduced level of oxidative stress and the inhibition of NF-κB and MAPK pathways.

Pharmacological Conditioning of the Heart: An Update on Experimental Developments and Clinical Implications

The aim of pharmacological conditioning is to protect the heart against myocardial ischemia-reperfusion (I/R) injury and its consequences. There is extensive literature that reports a multitude of different cardioprotective signaling molecules and mechanisms in diverse experimental protocols. Several pharmacological agents have been evaluated in terms of myocardial I/R injury. While results from experimental studies are immensely encouraging, translation into the clinical setting remains unsatisfactory. This narrative review wants to focus on two aspects: (1) give a comprehensive update on new developments of pharmacological conditioning in the experimental setting concentrating on recent literature of the last two years and (2) briefly summarize clinical evidence of these cardioprotective substances in the perioperative setting highlighting their clinical implications. By directly opposing each pharmacological agent regarding its recent experimental knowledge and most important available clinical data, a clear overview is given demonstrating the remaining gap between basic research and clinical practice. Finally, future perspectives are given on how we might overcome the limited translatability in the field of pharmacological conditioning.

[Perioperative cardioprotection - From bench to bedside : Current experimental evidence and possible reasons for the limited translation into the clinical setting]

Hintergrund

Ziel der perioperativen Kardioprotektion ist es, die Auswirkungen eines Ischämie- und Reperfusionsschadens zu minimieren. Aus anästhesiologischer Sicht spielt dieser Aspekt insbesondere in der Herzchirurgie bei Patienten mit Einsatz der Herz-Lungen-Maschine, aber auch allgemein bei längerfristigen hypotensiven Phasen oder perioperativen ischämischen Ereignissen im nichtkardiochirurgischen Setting eine wichtige Rolle. Im Laufe der letzten Jahre konnten diverse pharmakologische sowie nichtpharmakologische Strategien der Kardioprotektion identifiziert werden. Die Ergebnisse von Studien an isoliertem Gewebe sowie von tierexperimentellen In-vivo-Studien sind vielversprechend. Eine Translation dieser kardioprotektiven Strategien in die klinische Praxis ist bislang jedoch nicht gelungen. Große klinische Studien konnten keine signifikante Verbesserung des Outcome der Patienten zeigen.

Ziel der Arbeit

Dieser Übersichtsartikel gibt einen Überblick über die aktuelle experimentelle Evidenz pharmakologischer und nichtpharmakologischer Kardioprotektion. Außerdem sollen mögliche Gründe für die limitierte Translation diskutiert werden. Schließlich werden Möglichkeiten aufgezeigt, wie der Schritt „from bench to bedside“ in Zukunft doch noch gelingen könnte.

Material und Methoden

Narrative Übersichtsarbeit.

Ergebnisse und Diskussion

Trotz der vielversprechenden präklinischen experimentellen Ansätze zum Thema Kardioprotektion besteht nach wie vor eine große Diskrepanz zu den Ergebnissen aus großen klinischen Studien in der perioperativen Phase. Mögliche Gründe für die limitierte Translation könnten insbesondere Komorbiditäten und Komedikationen, die Wahl des Anästhesieverfahrens, aber auch die Wahl des Studiendesigns sein. Eine sorgfältige Studienplanung mit Berücksichtigung der genannten Probleme sowie ein simultaner Einsatz mehrerer kardioprotektiver Strategien mit dem Ziel eines additiven bzw. synergistischen Effekts stellen mögliche Ansätze für die Zukunft dar.

Perioperative Cardioprotection: General Mechanisms and Pharmacological Approaches

Cardioprotection encompasses a variety of strategies protecting the heart against myocardial injury that occurs during and after inadequate blood supply to the heart during myocardial infarction. While restoring reperfusion is crucial for salvaging myocardium from further damage, paradoxically, it itself accounts for additional cell death-a phenomenon named ischemia/reperfusion injury. Therefore, therapeutic strategies are necessary to render the heart protected against myocardial infarction. Ischemic pre- and postconditioning, by short periods of sublethal cardiac ischemia and reperfusion, are still the strongest mechanisms to achieve cardioprotection. However, it is highly impractical and far too invasive for clinical use. Fortunately, it can be mimicked pharmacologically, for example, by volatile anesthetics, noble gases, opioids, propofol, dexmedetomidine, and phosphodiesterase inhibitors. These substances are all routinely used in the clinical setting and seem promising candidates for successful translation of cardioprotection from experimental protocols to clinical trials. This review presents the fundamental mechanisms of conditioning strategies and provides an overview of the most recent and relevant findings on different concepts achieving cardioprotection in the experimental setting, specifically emphasizing pharmacological approaches in the perioperative context.

Sevoflurane preconditioning attenuates hypoxia/reoxygenation injury of H9c2 cardiomyocytes by activation of the HIF-1/PDK-1 pathway

Background

Sevoflurane preconditioning (SPC) can provide myocardial protective effects similar to ischemic preconditioning (IPC). However, the underlying molecular mechanism of SPC remains unclear. Studies confirm that hypoxia-inducible factor-1 (HIF-1) can transform cells from aerobic oxidation to anaerobic glycolysis by activating the switch protein pyruvate dehydrogenase kinase-1 (PDK-1), thus providing energy for the normal life activities of cells under hypoxic conditions. The purpose of this study was to investigate whether the cardioprotective effects of SPC are associated with activation of the HIF-1a/PDK-1 signal pathway.

Methods

The H9c2 cardiomyocytes hypoxia/reoxygenation model was established and treated with 2.4% sevoflurane at the end of equilibration. Lactate dehydrogenase (LDH) level, cell viability, cell apoptosis, mitochondrial membrane potential, key enzymes of glycolysis, ATP concentration of glycolysis were assessed after the intervention. Apoptosis related protein(Bcl-2, Bax), HIF-1a protein, and PDK-1 protein were assessed by western blot.

Results

Compared with the H/R group, SPC significantly increased the expression of HIF-1a, PDK-1, and Bcl-2 and reduced the protein expression of Bax, which markedly decreased the apoptosis ratio and Lactate dehydrogenase (LDH) level, increasing the cell viability, content of key enzymes of glycolysis, ATP concentration of glycolysis and stabilizing the mitochondrial membrane potential. However, the cardioprotective effects of SPC were disappeared by treatment with a HIF-1a selective inhibitor.

Conclusion

This study demonstrates that the cardioprotective effects of SPC are associated with the activation of the HIF-1a/PDK-1 signaling pathway. The mechanism may be related to increasing the content of key enzymes and ATP of glycolysis in the early stage of hypoxia.

Sevoflurane preconditioning inhibits cardiomyocyte injury induced by oxygen‑glucose deprivation by modulating TXNIP

The thioredoxin interaction protein (TXNIP) has been reported to be closely related to cell oxidative stress, apoptosis and inflammation. TXNIP is involved in the regulation of oxidative stress in lung and renal injury. However, it is unclear as to whether it participates in the protective effects of sevoflurane preconditioning in cardiomyocyte injury caused by oxidative stress in ischemia. In the present study, H9c2 cardiomyocytes were cultured with 0, 1.5, 2, 3.5, 5 or 6% sevoflurane for 3 h, followed by exposure to oxygen and glucose deprivation. The results demonstrated that oxygen and glucose deprivation induced an increase in TXNIP expression, lactate dehydrogenase (LDH) release, caspase‑3 activity, reactive oxygen species and malondialdehyde production. Preconditioning of the H9c2 cells with 3.5% sevoflurane suppressed TXNIP expression, LDH leakage, caspase‑3 activity, reactive oxygen species and malondialdehyde production, and it promoted cell viability. TXNIP overexpression reversed the effects of 3.5% sevoflurane preconditioning on caspase‑3 activity, reactive oxygen production and cell viability. Furthermore, TXNIP modulated p27 expression via PKB (protein kinase B/AKT) phosphorylation following preconditioning with 3.5% sevoflurane, and oxygen and glucose deprivation. On the whole these findings indicated that sevoflurane preconditioning protected the H9c2 cells against injury induced by oxygen and glucose deprivation by modulating TXNIP, AKT activation and p27 signaling.