Myocardial Ischemia-reperfusion Injury In Rats Research Articles

Investigation of the effects of cilostazol on the myocardial ischemia-reperfusion injury of rats.

<b><i>Background</i></b>. Myocardial ischemia, occurring as a consequence of imbalance between oxygen supply and demand, causes a rapid metabolic and structural<br /> impairment within the tissue. After a period of ischemia, sudden onset of reperfusion causes a transition to aerobic metabolism within living cells. Afterwards, emerging substrates initiate a chain of reactions leading to tissue injury. This situation is called “ischemia reperfusion injury”. Despite all technical advancements in anesthesia, myocardial protection and cardiac surgical techniques, we still face the clinical reflections of ischemia reperfusion (IR) injury.<br /> <b><i>Materials and methods</i></b>. The protective effect of cilostasole on IR injury in an animal model of experimental myocardial ischemia and reperfusion was investigated. In this regional myocardial ischemia model, male Wistar-Albino rats were used as subjects and they were allocated into three groups; ischemia (n=8), sham (n=8), and cilostazole (n=8). LAD was occluded for 45 minutes, and then reperfused for three hours. Rats received Cilostazole 20 mg/kg/d by gastric gavage once daily. During IR hemodynamic parameters were recorded. Serum analysis for CK-MB and Troponin T were analysed at 180th minute of ischemia. Ischemic zone was measured by dying with Evans Blue and infarct area was measured by dying with triphenyltetrazolium chloride.<br /> <b><i>Results.</i></b> Before the onset of LAD occlusion, as well as at 25th, 60th and 120th minutes of occlusion, all groups were similar in terms of blood pressure and pulse rate.<br /> The total area, affected area and necrotic area were calculated by using formulas; affected area ratio= affected area/total area X 100, necrotic area ratio = necrotic area/total affected area X 100, necrotic area and affected area ratio = necrotic area /affected area X 100.  Affected area and total area ratio was significantly higher in IR group, compared with cilostazole group (t=8.965; p<0.001). Similarly, necrotic area and total area ratio was higher in IR group, compared with cilostazole group (t=8.965; p<0.001). The necrotic area and affected area ratios were similar in IR and cilostazole groups (t=0.245; p=0.810). CK-MB level differences were not statistically significant between two groups (Z=0.382; p=0.721).<br /> Troponin levels were similar between IR and cilostazole groups and the difference was not statistically significant (Z=0.630; p=0.574). Pathological specimens of the heart were scanned for myocytolysis, PMNL and hemorrhage.  The difference between mean value of MDA enzyme levels were statistically significant (p<0.001) between all groups.  MDA enzyme levels, from higher to lower was IR, cilostazole and Sham group.  SOD levels (F=5.910; p=0.009) were significantly lower in Sham group when compared with IR group (p=0.008). The differences between Sham and cilostazole groups and IR and cilostazole gropus were not statistically significant (p=0.008). According to planimetric values and enzyme levels, cilostazole was found to be effective in reducing the ischemic zone, without effecting the necrotic zone in cardiac ischemia reperfusion damage. Therefore cilostazole has protective effects agains ischemia reperfusion damage.<br /> <br /> <b>Conclusion</b>. This study explored how cilostazol affects myocardial ischemia-reperfusion injury in rats, finding that cilostazol administration during reperfusion may protect against such injury. Through various analyses, we observed positive outcomes associated with cilostazol treatment, suggesting its potential in reducing myocardial damage. Further research is needed to understand the underlying mechanisms and optimize therapeutic strategies, but our findings highlight cilostazol's promise in improving clinical outcomes in cardiac interventions.

Qilong capsule prevents myocardial ischemia/reperfusion injury by inhibiting platelet activation via the platelet CD36 signaling pathway

Ethnopharmacological relevanceQilong capsule (QC) is developed from the traditional Chinese medicine formula Buyang Huanwu Decoction, which has been clinically used to invigorate Qi and promote blood circulation to eliminate blood stasis. Myocardial ischemia‒reperfusion injury (MIRI) can be attributed to Qi deficiency and blood stasis. However, the effects of QC on MIRI remain unclear. Aim of the studyThis study aimed to investigate the protective effect and possible mechanism of QC on platelet function in MIRI rats. Materials and methodsThe left anterior descending artery of adult Sprague‒Dawley rats was ligated for 30 min and then reperfused for 120 min with or without QC treatment. Then, the whole blood viscosity, plasma viscosity, coagulation, platelet adhesion rate, platelet aggregation, and platelet release factors were evaluated. Platelet CD36 and its downstream signaling pathway-related proteins were detected by western blotting. Furthermore, the active components of QC and the molecular mechanism by which QC regulates platelet function were assessed via molecular docking, platelet aggregation tests in vitro and BLI analysis. ResultsWe found that QC significantly reduced the whole blood viscosity, plasma viscosity, platelet adhesion rate, and platelet aggregation induced by ADP or AA in rats with MIRI. The inhibition of platelet activation by QC was associated with reduced levels of β-TG, PF-4, P-selectin and PAF. Mechanistically, QC effectively attenuated the expression of platelet CD36 and thus inhibited the activation of Src, ERK5, and p38. The active components of QC apparently suppressed platelet aggregation in vitro and regulated the CD36 signaling pathway. ConclusionsQC improves MIRI-induced hemorheological disorders, which might be partly attributed to the inhibition of platelet activation via CD36-mediated platelet signaling pathways.

Bioinformatics integration reveals key genes associated with mitophagy in myocardial ischemia-reperfusion injury

BackgroundMyocardial ischemia is a prevalent cardiovascular disorder associated with significant morbidity and mortality. While prompt restoration of blood flow is essential for improving patient outcomes, the subsequent reperfusion process can result in myocardial ischemia–reperfusion injury (MIRI). Mitophagy, a specialized autophagic mechanism, has consistently been implicated in various cardiovascular disorders. However, the specific connection between ischemia–reperfusion and mitophagy remains elusive. This study aims to elucidate and validate central mitophagy-related genes associated with MIRI through comprehensive bioinformatics analysis.MethodsWe acquired the microarray expression profile dataset (GSE108940) from the Gene Expression Omnibus (GEO) and identified differentially expressed genes (DEGs) using GEO2R. Subsequently, these DEGs were cross-referenced with the mitophagy database, and differential nucleotide sequence analysis was performed through enrichment analysis. Protein–protein interaction (PPI) network analysis was employed to identify hub genes, followed by clustering of these hub genes using cytoHubba and MCODE within Cytoscape software. Gene set enrichment analysis (GSEA) was conducted on central genes. Additionally, Western blotting, immunofluorescence, and quantitative polymerase chain reaction (qPCR) analyses were conducted to validate the expression patterns of pivotal genes in MIRI rat model and H9C2 cardiomyocytes.ResultsA total of 2719 DEGs and 61 mitophagy-DEGs were identified, followed by enrichment analyses and the construction of a PPI network. HSP90AA1, RPS27A, EEF2, EIF4A1, EIF2S1, HIF-1α, and BNIP3 emerged as the seven hub genes identified by cytoHubba and MCODE of Cytoscape software. Functional clustering analysis of HIF-1α and BNIP3 yielded a score of 9.647, as determined by Cytoscape (MCODE). In our MIRI rat model, Western blot and immunofluorescence analyses confirmed a significant elevation in the expression of HIF-1α and BNIP3, accompanied by a notable increase in the ratio of LC3II to LC3I. Subsequently, qPCR confirmed a significant upregulation of HIF-1α, BNIP3, and LC3 mRNA in the MIRI group. Activation of the HIF-1α/BNIP3 pathway mediates the regulation of the degree of Mitophagy, thereby effectively reducing apoptosis in rat H9C2 cardiomyocytes.ConclusionsThis study has identified seven central genes among mitophagy-related DEGs that may play a pivotal role in MIRI, suggesting a correlation between the HIF-1α/BNIP3 pathway of mitophagy and the pathogenesis of MIRI. The findings highlight the potential importance of mitophagy in MIRI and provide valuable insights into underlying mechanisms and potential therapeutic targets for further exploration in future studies.

Hydromorphone hydrochloride preconditioning combined with postconditioning attenuates myocardial ischemia/reperfusion injury in rats by improving mitochondrial function and activating the PI3K/Akt signaling pathway.

Thrombolytic therapy or percutaneous coronary intervention for myocardial infarction often cause myocardial ischemia/reperfusion injury (MIRI) and poor prognosis of patients. This study aimed to explore the protective effect and potential mechanism of hydromorphone hydrochloride (HH) on MIRI. Fifty Sprague-Dawley male rats were randomly divided into Sham group, I/R group, HH-pre group, HH-post group, and HH-pre + post group. Except Sham group, MIRI models were established by ligating and relaxing the left anterior descending coronary artery, followed by tail vein injection of HH (0.3 μmol/L) 10 min before ligation (HH-pre group), 10 min after reperfusion (HH-post group), and twice at the above two time points (HH-pre + post group). After intervention, the cardiac function of rats was evaluated by echocardiography, and the levels of myocardial injury markers, oxidative stress indicators, and mitochondrial function indicators were detected. Next, the myocardial infarction area was evaluated by 2,3,5-triphenyltetrazolium chloride staining, mitochondrial biogenesis, and phosphoinositide 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway by western blot. Compared with the I/R group, HH intervention improved cardiac function, decreased myocardial infarction area, reduced serum myocardial injury markers, alleviated oxidative stress, improved mitochondrial function, up-regulated mitochondrial biogenesis, and activated PI3K/Akt signaling pathway. Moreover, the HH-pre + post group was superior to the HH-pre and HH-post groups in the above aspects. Collectively, HH had protective effect on MIRI rats, and HH preconditioning combined with postconditioning showed optimal efficacy. Such efficacy may be achieved by promoting mitochondrial biogenesis to improve mitochondrial function and reduce oxidative stress, and activating the PI3K/Akt signaling pathway.

Effect of electroacupuncture on ventricular structure and function in rats with myocardial ischemia-reperfusion injury.

To observe the effect of electroacupuncture (EA) on changes of ventricular structure and function in rats with myocardial ischemia-reperfusion injury (MIRI), so as to explore its potential mechanisms underlying improvement of ventricular remodeling after MIRI. Forty male SD rats were randomly divided into 4 groups：sham operation group, model group, EA group and medication (sacubactril valsartan, LCZ696) group, with 10 rats in each group. The MIRI model was established by ligation of the left anterior descending coronary artery and reperfusion. EA (2 Hz/100 Hz, 2 mA) was applied to bilateral "Neiguan" (PC6) for 20 min, once every other day for 21 d. Rats of the medication group received gavage of LCZ696 (60 mg·kg-1·d-1). After the intervention, echocardiography was used to detect the ejection fraction (EF) and fractional shortening (FS) of the left ventricle, and the contents of serum tumor necrosis factor-α(TNF-α), vascular cell adhesion molecule-1(VCAM-1) and intercellular cell adhesion molecule-1(ICAM-1) were assayed by enzyme-linked immunosorbent assay. The pathological changes of myocardial tissue were observed after HE staining. The Masson staining was used to evaluate the myocardial collagen deposition and myocardial fibrosis. The mRNA expression levels of collagen Ⅰ and Ⅲ and connective tissue growth factor (CTGF) in the myocardial tissue were detected by quantitative real-time PCR, and the expression levels of IL-1β and IL-18 were detected by Western blot. In contrast to the sham operation group, the EF and FS levels of the left ventricle were ob-viously decreased (P<0.001), while the contents of serum TNF-α, VCAM-1 and ICAM-1, the proportion of myocardial fibrosis area, the mRNA expression levels of myocardial collagen Ⅰ, collagen Ⅲ and CTGF, the expression levels of IL-1β and IL-18 were significantly increased (P<0.001, P<0.000 1, P<0.05, P<0.01) in the model group. Compared with the model group, the EF and FS levels were remarkably increased (P<0.01), whereas the contents of serum TNF-α, VCAM-1 and ICAM-1, the proportion of myocardial fibrosis area, the mRNA expression levels of myocardial collagen Ⅰ, collagen Ⅲ and CTGF, and the expression levels of IL-1β and IL-18 were significantly down-regulated (P<0.001, P<0.01, P<0.05) in both the medication and EA groups. No significant differences were found between the EA and medication groups in all the indexes mentioned above. EA can improve the left-ventricular fibrosis and function, delay or reverse ventricular remodeling in MIRI rats, which may be related to its functions in down-regulating myocardial inflammatory response and mRNA expression levels of myocardial collagen Ⅰ, collagen Ⅲ and CTGF.

Intramyocardial delivery of injectable hydrogel with arctigenin alleviated myocardial ischemia-reperfusion injury in rats.

Arctigenin belongs to a major bioactive component of Fructus arctii and has been found with cardioprotective effects on rats with ischemia-reperfusion (I/R) injury. The application of arctigenin is limited due to poor water solubility and low bioavailability. Hydrogel drug delivery systems can improve the efficacy and safety of drugs, increase drug utilization, and reduce side effects. We hypothesized that hydrogels containing arctigenin would facilitate the effect of arctigenin and alleviate I/R injury in the rat heart. Presently, adult Sprague-Dawley (SD) rats were subjected to 1h of I/R injury, then hydrogels comprising arctigenin were implanted into the myocardium of rats. Triphenyl tetrazolium chloride staining, hematoxylin-eosin staining, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining and Western blot were performed for evaluating the infarct size, histopathological, and vital protein alterations of hearts. It was discovered that the hydrogel combined with arctigenin abated apoptosis and reduced infarct size. In addition, the results of echocardiography and Masson staining suggested that the hydrogel with arctigenin improved cardiac function, restrained myocardial fibrosis, and activated AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1). Collectively, the injectable hydrogel delivery system enhances the effect of arctigenin, which may play a protective role in I/R injury by activating AMPK and SIRT1.

Retracted: Effects of Aspirin on Myocardial Ischemia-Reperfusion Injury in Rats through STAT3 Signaling Pathway.

[This retracts the article DOI: 10.1155/2021/9931885.].

Shuxuening Injection Inhibits Apoptosis and Reduces Myocardial Ischemia-Reperfusion Injury in Rats through PI3K/AKT Pathway.

To investigate the main components and potential mechanism of Shuxuening Injection (SXNI) in the treatment of myocardial ischemia-reperfusion injury (MIRI) through network pharmacology and in vivo research. The Traditional Chinese Medicine Systems Pharmacology (TCMSP) and PharmMapper databases were used to extract and evaluate the effective components of Ginkgo biloba leaves, the main component of SXNI. The Online Mendelian Inheritance in Man (OMIM) and GeneCards databases were searched for disease targets and obtain the drug target and disease target intersections. The active ingredient-target network was built using Cytoscape 3.9.1 software. The STRING database, Metascape online platform, and R language were used to obtain the key targets and signaling pathways of the anti-MIRI effects of SXNI. In order to verify the therapeutic effect of different concentrations of SXNI on MIRI in rats, 60 rats were first divided into 5 groups according to random number table method: the sham operation group, the model group, SXNI low-dose (3.68 mg/kg), medium-dose (7.35 mg/kg), and high-dose (14.7 mg/kg) groups, with 12 rats in each group. Then, another 60 rats were randomly divided into 5 groups: the sham operation group, the model group, SXNI group (14.7 mg/kg), SXNI+LY294002 group, and LY294002 group, with 12 rats in each group. The drug was then administered intraperitoneally at body weight for 14 days. The main biological processes were validated using in vivo testing. Evans blue/triphenyltetrazolium chloride (TTC) double staining, hematoxylin-eosin (HE) staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, enzyme-linked immunosorbent assay (ELISA), and Western blot analysis were used to investigate the efficacy and mechanism of SXNI in MIRI rats. Eleven core targets and 30 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were selected. Among these, the phosphoinositide 3-kinase (PI3K)/ protein kinase B (AKT) pathway was closely related to SXNI treatment of MIRI. In vivo experiments showed that SXNI reduced the myocardial infarction area in the model group, improved rat heart pathological damage, and reduced the cardiomyocyte apoptosis rate (all P<0.01). After SXNI treatment, the p-PI3K/PI3K and p-AKT/AKT ratios as well as B-cell lymphoma-2 (Bcl-2) protein expression in cardiomyocytes were increased, while the Bax and cleaved caspase 3 protein expression levels were decreased (all P<0.05). LY294002 partially reversed the protective effect of SXNI on MIRI. SXNI protects against MIRI by activating the PI3K/AKT signaling pathway.

Mechanistic study of electroacupuncture preconditioning in alleviating myocardial ischemia-reperfusion injury in rats: involvement of mTOR/ROS signaling pathway to inhibit ferroptosis

Purpose The objective of this study was to investigate the mechanism of electroacupuncture pretreatment in reducing myocardial ischemia-reperfusion injury in rats. Materials and methods The comparison of HR among the different groups did not yield statistically significant differences (p > 0.05). Additionally, the trend of HR change at different time points within each group was not statistically significant (p > 0.05). In contrast, the comparison of SBP among the different groups showed statistically significant differences (p < 0.05). Furthermore, the trend of SBP change at different time points within each group exhibited significant differences (p < 0.05). Results Compared to the Sham group, rats in the I/R group and EA control group showed a significant decrease in EF, FS, SOD, p-mTOR/mTOR, GPX4, and FTH1, and an increase in CK-MB, cTnI, LDH, iron, ROS, MDA, ACSL4, and NCOA4 (p < 0.05). Compared to EA control group, rats in the EA group exhibited a significant increase in EF, FS, SOD, p-mTOR/mTOR, GPX4, and FTH1, and a decrease in CK-MB, cTnI, LDH, iron, ROS, MDA, ACSL4, and NCOA4 (p < 0.05). Compared to the EA group, rats in the EA + RAP group showed a significant decrease in EF, FS, SOD, p-mTOR/mTOR, GPX4, and FTH1, and an increase in CK-MB, cTnI, LDH, iron, ROS, MDA, ACSL4, and NCOA4 (p < 0.05). Conclusions Electroacupuncture preconditioning confers protective effects against myocardial ischemia-reperfusion injury in rats. Its mechanism may involve the activation of the mTOR/ROS signaling pathway by electroacupuncture to inhibit ferroptosis.

Dexmedetomidine Preconditioning Attenuates Myocardial Ischemia/Reperfusion Injury in Rats by Suppressing Mitophagy Via Activating Α2-Adrenergic Receptor.

Dexmedetomidine (DEX), a specific α2-adrenergic receptor agonist, is protective against myocardial ischemia/reperfusion injury (MIRI). However, the association between DEX preconditioning-induced cardioprotection and mitophagy suppression remains unclear. Hence, we aimed to investigate whether DEX preconditioning alleviates MIRI by suppressing mitophagy via α2-adrenergic receptor activation. Sixty isolated rat hearts were treated with or without DEX before inducing ischemia and reperfusion; an α2-adrenergic receptor antagonist, yohimbine (YOH), was also administered before ischemia, alone or with DEX. The heart rate (HR), left ventricular diastolic pressure (LVDP), left ventricular end-diastolic pressure (LVEDP), maximal and minimal rate of left ventricular pressure development (±dp/dtmax), and myocardial infarction size were measured. The mitochondrial ultrastructure and autophagosomes were assessed using transmission electron microscopy. Mitochondrial membrane potential and reactive oxygen species (ROS) levels were measured using JC-1 and dichloride hydrofluorescein diacetate assays, respectively. The expression levels of the mitophagy-associated proteins Beclin1, LC3II/I ratio, p62, PINK1, and Parkin were detected by western blotting. Compared with the control group, in the ischemia/reperfusion group, the HR, LVDP, and ±dp/dtmax were remarkably decreased (p< 0.05), whereas LVEDP and infarct sizes were significantly increased (p< 0.05). DEX preconditioning significantly improved cardiac dysfunction reduced myocardial infarction size, maintained mitochondrial structural integrity, increased mitochondrial membrane potential, inhibited autophagosomes formation, and decreased ROS production and Beclin1, LC3II/I ratio, PINK1, Parkin, and p62 expression(p< 0.05). When DEX and YOH were combined, YOH canceled the effect of DEX, whereas the use of YOH alone had no effect. Therefore, DEX preconditioning was cardioprotective against MIRI in rats by suppressing mitophagy via α2-adrenergic receptor activation.

Dexmedetomidine pre-conditioning induces inhibition of ROS in myocardial ischemia-reperfusion injury in rats through AMPK pathway

Purpose: To elucidate the basis for the cardioprotective effect of dexmedetomidine pre-treatment on ROS-induced myocardial ischemia-reperfusion injury (IRI) in rats.Methods: Sixty Sprague-Dawley (SD) rats were assigned to sham, model and dexmedetomidine intervention groups, each having 20 rats. Myocardial IRI was induced in the model and dexmedetomidine intervention groups using modified suture method. In sham group, chests of rats were opened, but without ligation, while dexmedetomidine intervention group was pre-treated with dexmedetomidine (5 μg/kg) before establishment of the IRI model. Protein expressions of adenosine 5‘-monophosphate (AMP)-activated protein kinase (AMPK) was determined by Western blot assay. Mean fluorescence intensity of ROS was measured using flow cytometry.Results: AMPK protein was significantly down-regulated in model rats, relative to sham rats, but significantly higher in dexmedetomidine intervention rats (p &lt; 0.05). In model rats, mean ROS fluorescence intensity and degree of apoptosis of cardiomyocytes were higher than the corresponding values in sham rats (p &lt; 0.05), but lower in dexmedetomidine intervention group.Conclusion: Dexmedetomidine reduces oxidative stress in myocardial tissue and exerts a protective role by activating AMPK pathway and inhibiting mitochondrial generation of ROS. Therefore, this compound might have a potential clinical role in the management of IRI.

Mechanism of DYRK1a in myocardial ischemia-reperfusion injury by regulating ferroptosis of cardiomyocytes.

This study aimed to explore the role and mechanism of DYRK1a regulating ferroptosis of cardiomyocytes during myocardial ischemia-reperfusion injury (MIRI). H9c2 cells treated with oxygen-glucose deprivation/reoxygenation (OGD/R) were used as MIRI cell models and transfected with sh-DYRK1a or/and erastin. Cell viability, apoptosis, and DYRK1a mRNA/protein expression were measured accordingly. The levels of reactive oxygen species (ROS), iron, malondialdehyde (MDA), and glutathione (GSH) were determined. The expression of ferroptosis-related proteins (GPX4, SLC7A11, ACSL4, and TFR1) was detected using western blotting. The MIRI rat model was established to explore the possible role of DYRK1a suppression in cell injury and ferroptosis. OGD/R cells showed elevated mRNA and protein expression for DYRK1a. OGD/R cells transfected with sh-DYRK1a showed elevated cell viability, GSH content, increased GPX4 and SLC7A11 expression, suppressed iron content, MDA, ROS, ACSL4, and TFR1 expression, and reduced apoptosis rate, whereas co-transfection of sh-DYRK1a with erastin reversed the attenuation of sh-DYRK1a on MIRI. The suppressive effect of sh-DYRK1a on MI/R injury was confirmed in an MIRI rat model. DYRK1a mediates ferroptosis of cardiomyocytes to deteriorate MIRI progression.

Electroacupuncture preconditioning protects against myocardial ischemia-reperfusion injury by modulating dynamic inflammatory response

BackgroundThe protective effects of electroacupuncture (EA) preconditioning against myocardial ischemia-reperfusion injury (MIRI) have been reported. However, the underlying mechanism remains unclear. Recent research has indicated that the dynamic inflammatory response following MIRI plays an essential role in the progression of myocardial injury. This study aimed to investigate the myocardial protective effects of EA preconditioning on MIRI in rats and to explore the relevant mechanism from the perspective of dynamic inflammatory response. MethodsA MIRI model was employed, and the rats were subjected to EA on Neiguan for four days prior to modeling. The myocardial protective effect of EA preconditioning was evaluated by echocardiography, Evans blue and triphenyltetrazolium chloride staining. Real-time polymerase chain reaction, Western blot, hematoxylin & eosin staining, and immunohistochemistry were utilized to detect the content of mitochondrial DNA, NOD receptor family protein 3 (NLRP3) inflammasome activation, neutrophil recruitment and macrophage infiltration in blood samples and myocardium below the ligation. ResultsWe found that EA preconditioning could accelerate the recovery of left ventricle function after MIRI and reduce the myocardial infarction area, thereby protecting the myocardium against MIRI. Furthermore, EA preconditioning was observed to ameliorate mitochondrial impairment, reduce the level of plasma mitochondrial DNA, modulate NLRP3 inflammasome activation, attenuate neutrophil infiltration, and promote the polarization of M1 macrophages towards M2 macrophages in the myocardium after MIRI. ConclusionEA preconditioning could reduce plasma mtDNA, suppress overactivation of the NLRP3 inflammasome, facilitate the transition from the acute pro-inflammatory phase to the anti-inflammatory reparative phase after MIRI, and ultimately confer cardioprotective benefits.

Huoxin Pill Reduces Myocardial Ischemia Reperfusion Injury in Rats via TLR4/NFκB/NLRP3 Signaling Pathway.

To explore the protective effect of Huoxin Pill (HXP) on acute myocardial ischemia-reperfusion (MIRI) injury in rats. Seventy-five adult SD rats were divided into the sham-operated group, model group, positive drug group (diltiazem hydrochloride, DH), high dose group (24 mg/kg, HXP-H) and low dose group (12 mg/kg, HXP-L) of Huoxin Pill (n=15 for every group) according to the complete randomization method. After 1 week of intragastric administration, the left anterior descending coronary artery of the rat's heart was ligated for 45 min and reperfused for 3 h. Serum was separated and the levels of creatine kinase (CK), creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH), superoxide dismutase (SOD), and malondialdehyde (MDA), hypersensitive C-reactive protein (hs-CRP) and interleukin-1β (IL-1β) were measured. Myocardial ischemia rate, myocardial infarction rate and myocardial no-reflow rate were determined by staining with Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC). Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) and Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine (BATMAN) databases were used to screen for possible active compounds of HXP and their potential therapeutic targets; the results of anti-inflammatory genes associated with MIRI were obtained from GeneCards, Drugbank, Online Mendelian Inheritance in Man (OMIM), and Therapeutic Target Datebase (TTD) databases was performed; Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were used to analyze the intersected targets; molecular docking was performed using AutoDock Tools. Western blot was used to detect the protein expression of Toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NFκB)/NOD-like receptor protein 3 (NLRP3). Compared with the model group, all doses of HXP significantly reduced the levels of LDH, CK and CK-MB (P<0.05, P<0.01); HXP significantly increased serum activity of SOD (P<0.05, P<0.01); all doses of HXP significantly reduced the levels of hs-CRP and IL-1β (P<0.05, P<0.01) and the myocardial infarction rate and myocardial no-reflow rate (P<0.01). GO enrichment analysis mainly involved positive regulation of gene expression, extracellular space and identical protein binding, KEGG pathway enrichment mainly involved PI3K-Akt signaling pathway and lipid and atherosclerosis. Molecular docking results showed that kaempferol and luteolin had a better affinity with TLR4, NFκB and NLRP3 molecules. The protein expressions of TLR4, NFκB and NLRP3 were reduced in the HXP group (P<0.01). HXP has a significant protective effect on myocardial ischemia-reperfusion injury in rats, and its effect may be related to the inhibition of redox response and reduction of the inflammatory response by inhibiting the TLR4NFκB/NLRP3 signaling pathway.

PM2.5-Induced Cardiac Structural Modifications and Declined Pro-Survival Signalling Pathways Are Responsible for the Inefficiency of GSK-3β Inhibitor in Attenuating Myocardial Ischemia-Reperfusion Injury in Rats.

Circulatory GSK3β is recognized as a biomarker and therapeutic target for diseases, including myocardial diseases. However, its potential as a target for myocardial ischemia-reperfusion injury (IR) in the presence of PM2.5 exposure is unclear. Wistar rats underwent IR following either a 21-day or single exposure to PM2.5 at a concentration of 250 µg/m3. The effects of GSK3β inhibitor on cardiac physiology, tissue injury, mitochondrial function, and the PI3K/AKT/GSK3β signalling axis were examined. The inhibitor was not effective in improving hemodynamics or reducing IR-induced infarction in the myocardium exposed to PM2.5 for 21 days. However, for a single-day exposure, the inhibitor showed potential in mitigating cardiac injury. In normal hearts undergoing IR, the inhibitor activated the PI3K/AKT signalling pathway, improved mitochondrial function, and reduced oxidative stress. These positive effects were not observed in PM2.5-exposed rats. Furthermore, the inhibitor stimulated autophagy in hearts exposed to PM2.5 for 21 days and subjected to IR, resulting in increased mTOR expression and decreased AMPK expression. In normal hearts and those exposed to a single dose of PM2.5, the inhibitor effectively activated the PI3K/Akt/AMPK axis. These findings suggest that GSK3β may not be a reliable therapeutic target for IR in the presence of chronic PM2.5 exposure.

CREB-binding protein and HIF-1α/β-catenin to upregulate miR-322 and alleviate myocardial ischemia-reperfusion injury.

Myocardial ischemia/reperfusion injury (MIRI) is a prevalent condition associated with numerous critical clinical conditions. miR-322 has been implicated in MIRI through poorly understood mechanisms. Our preliminary analysis indicated potential interaction of CREB-binding protein (CBP), a transcriptional coactivator and acetyltransferase, with HIF-1α/β-catenin, which might regulate miR-322 expression. We, therefore, hypothesized that CBP/HIF-1α/β-catenin/miR-322 axis might play a role in MIRI. Rat cardiomyocytes subjected to oxygen-glucose deprivation /reperfusion (OGD/R) and Langendorff perfused heart model were used to model MIRI in vitro and in vivo, respectively. We used various techniques such as CCK-8 assay, transferase dUTP nick end labeling staining, western blotting, RT-qPCR, chromatin immunoprecipitation (ChIP), dual-luciferase assay, co-immunoprecipitation (Co-IP), hematoxylin and eosin staining, and TTC staining to assess cell viability, apoptosis, and the levels of CBP, HIF-1α, β-catenin, miR-322, and acetylation. Our results indicate that OGD/R in cardiomyocytes decreased CBP/HIF-1α/β-catenin/miR-322 expression, increased cell apoptosis and cytokines, and reduced cell viability. However, overexpression of CBP or miR-322 suppressed OGD/R-induced cell injury, while knockdown of HIF-1α/β-catenin further exacerbated the damage. HIF-1α/β-catenin bound to miR-322 promoter to promote its expression, while CBP acetylated HIF-1α/β-catenin for stabilization. Overexpression of CBP attenuated MIRI in rats by acetylating HIF-1α/β-catenin to stabilize their expression, resulting in stronger binding of HIF-1α/β-catenin with the miR-322 promoter and subsequent increased miR-322 levels. Therefore, activating CBP/HIF-1α/β-catenin/miR-322 signaling may be a potential approach to treat MIRI.

Retracted: Protective Effect of Sufentanil on Myocardial Ischemia-Reperfusion Injury in Rats by Inhibiting Endoplasmic Reticulum Stress.

[This retracts the article DOI: 10.1155/2022/6267720.].

Astragaloside IV attenuates cardiac hypertrophy in rats born from mothers with intrauterine hypoxia through the PKCβII/Egr‑1 pathway.

Astragaloside IV (AS-IV) is a naturally occurring agent that confers several wide-ranging reported pharmacological effects, such as cardioprotective, antioxidative and pro-angiogenic activities. Although it was previously reported that AS-IV could attenuate neonatal rat myocardial ischemia-reperfusion injury, the possible effects of AS-IV on the development of cardiac hypertrophy associated with intrauterine hypoxia (IUH) remain unclear. The present study established a model of IHU by placing the pregnant rats in a plexiglass chamber with an oxygen supply of 10% before neonatal rat delivery. To investigate the in vivo effect of AS-IV on cardiac hypertrophy, neonatal rats with hypertension were randomly grouped to receive AS-IV (20 mg/kg), AS-IV (40 mg/kg), AS-IV (80 mg/kg) or vehicle for 12 weeks, followed by left ventricular (LV) hemodynamics and heart tissue histological analysis. Rats born from mothers with IHU displayed pathological features of cardiac hypertrophy. However, AS-IV 40 and 80 mg/kg significantly decreased the heart/body weight (BW), LV mass (LVM)/BW, heart mass/tibia length (TL) and LVM/TL ratios. H&E staining showed that 40 and 80 mg/kg AS-IV prevented the morphometric changes induced by IHU. According to data from LV hemodynamics measurements, AS-IV 80 mg/kg reversed the increased systolic blood pressure, diastolic blood pressure, LV systolic pressure, LV end-diastolic pressure, dP/dt maximum and heart rate induced by IHU. Mechanistically, ERK1/2 activation and early growth response 1 (Egr-1) protein expression were both upregulated by IHU induction, which was reversed by AS-IV treatment. In conclusion, these data suggested that AS-IV could attenuate cardiac hypertrophy in neonatal rats born from mothers with IHU through the protein kinase C β type isoform 2/Egr-1 pathway, but the underlying mechanism requires further investigation.

Effects of electroacupuncture pretreatment on GABAA receptor of fastigial nucleus and sympathetic nerve activity in rats with myocardial ischemia reperfusion injury

To observe the effects of electroacupuncture (EA) pretreatment on cardiac function, sympathetic nerve activity, indexes of myocardial injury and GABAA receptor in fastigial nucleus in rats with myocardial ischemia reperfusion injury (MIRI), and to explore the neuroregulatory mechanism of EA pretreatment in improving MIRI. A total of 60 male SD rats were randomly divided into a sham operation group, a model group, an EA group, an agonist group and an agonist+EA group, 12 rats in each group. The MIRI model was established by ligation of the left anterior descending coronary artery. EA was applied at bilateral "Shenmen" (HT 7) and "Tongli" (HT 5) in the EA group and the agonist+EA group, with continuous wave, in frequency of 2 Hz and intensity of 1 mA, 30 min each time, once a day for 7 consecutive days. After intervention, the MIRI model was established. In the agonist group, the muscone (agonist of GABAA receptor, 1 g/L) was injected in fastigial nucleus for 7 consecutive days before modeling, 150 μL each time, once a day. In the agonist+EA group, the muscone was injected in fastigial nucleus 30 min before EA intervention. The data of electrocardiogram was collected by PowerLab standard Ⅱ lead, and ST segment displacement and heart rate variability (HRV) were analyzed; the serum levels of norepinephrine (NE), creatine kinase isoenzyme MB (CK-MB) and cardiac troponin I (cTnI) were detected by ELISA; the myocardial infarction area was measured by TTC staining; the morphology of myocardial tissue was observed by HE staining; the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were detected by immunohistochemistry and real-time PCR. Compared with the sham operation group, in the model group, ST segment displacement and ratio of low frequency to high frequency (LF/HF) of HRV were increased (P<0.01), HRV frequency domain analysis showed enhanced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were increased (P<0.01), the percentage of myocardial infarction area was increased (P<0.01), myocardial fiber was broken and interstitial edema was serious, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were increased (P<0.01). Compared with the model group, in the EA group, ST segment displacement and LF/HF ratio were decreased (P<0.01), HRV frequency domain analysis showed reduced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were decreased (P<0.01), the percentage of myocardial infarction area was decreased (P<0.01), myocardial fiber breakage and interstitial edema were lightened, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were decreased (P<0.01). Compared with the EA group, in the agonist group and the agonist+EA group, ST segment displacement and LF/HF ratio were increased (P<0.01), HRV frequency domain analysis showed enhanced sympathetic nerve excitability, the serum levels of NE, CK-MB and cTnI were increased (P<0.01), the percentage of myocardial infarction area was increased (P<0.01), myocardial fiber breakage and interstitial edema were aggravated, the positive expression and mRNA expression of GABAA receptor in fastigial nucleus were increased (P<0.01). EA pretreatment can improve the myocardial injury in MIRI rats, and its mechanism may be related to the inhibition of GABAA receptor expression in fastigial nucleus, thereby down-regulating the excitability of sympathetic nerve.

Sevoflurane exerts protection against myocardial ischemia–reperfusion injury and pyroptosis through the circular RNA PAN3/microRNA-29b-3p/stromal cell-derived factor 4 axis

ObjectiveSevoflurane is suggested to exert protective functions against myocardial ischemia–reperfusion injury (MIRI). However, the particular mechanism remains elusive. Therefore, this research explored the mechanism of sevoflurane in MIRI-induced damage and pyroptosis. MethodsSubsequent to gain-or loss-of-function assays or/and sevoflurane treatment, the MIRI model was developed in rats. Cardiac function and body and heart weight of rats were evaluated, followed by measurement of apoptosis and creatine kinase MB (CK-MB), lactate dehydrogenase (LDH), and pyroptosis-related protein levels. After loss-of-function assays or/and sevoflurane treatment in human cardiomyocytes (HCMs), the hypoxia/reoxygenation (H/R) model was constructed. In HCMs, cell viability, apoptosis, and pyroptosis-related proteins were detected. Circular RNA PAN3 (circPAN3), microRNA (miR)-29b-3p, and stromal cell-derived factor 4 (SDF4) expression was determined in rat myocardial tissues and HCMs. Mechanistically, interactions among circPAN3, miR-29b-3p, and SDF4 were analyzed. ResultsMIRI modeling increased miR-29b-3p expression and diminished circPAN3 and SDF4 expression in H/R-treated HCMs and MIRI rats, which was nullified by sevoflurane preconditioning. Mechanistically, circPAN3 negatively targeted miR-29b-3p to upregulate SDF4. Moreover, sevoflurane preconditioning reduced heart weight/body weight ratio, LDH, CK-MB, myocardial infarct size, left ventricular end-diastolic pressure, apoptosis, and pyroptosis, while elevating the increase and decrease of left ventricular pressure (±dp/dt max) and left ventricular systolic pressure in MIRI rats. In addition, sevoflurane preconditioning augmented viability while diminishing apoptosis and pyroptosis in H/R-treated HCMs. Moreover, circPAN3 silencing or miR-29b-3p overexpression abrogated alleviatory effects of sevoflurane on myocardial injury and pyroptosis in vitro. ConclusionSevoflurane treatment ameliorated myocardial injury and pyroptosis in MIRI via circPAN3/miR-29b-3p/SDF4 axis.