Cardioprotective Effect of Electroacupuncture Pretreatment on Myocardial Ischemia/Reperfusion Injury via Antiapoptotic Signaling

Restoring the Autonomic Balance in an Atrial Fibrillation Rat Model by Electroacupuncture at the Neiguan Point

OBJECTIVES

Autonomic nervous activity imbalance plays an important role in atrial fibrillation (AF). AF can be treated by acupuncture at the Neiguan point (PC6), but the mechanism remains elusive. Here, we investigated autonomic nervous system activity in electroacupuncture (EA) at PC6 in a rat AF model.

MATERIAL AND METHODS

In this study, we established a rat AF model via tail vein injection with ACh-CaCl2 for ten consecutive days with or without EA at PC6. AF inducibility and heart rate variability (HRV) were assessed by electrocardiogram. Next, we completed in vivo recording of the activity of cervical sympathetic and vagal nerves, respectively. Finally, the activities of brain regions related to autonomic nerve regulation were assessed by c-Fos immunofluorescence and multichannel recording.

RESULTS

EA at PC6 decreased AF inducibility and prevented changes in HRV caused by ACh-CaCl2 injection. Meanwhile, EA at PC6 reversed the increased sympathetic and decreased vagal nerve activity in AF rats. Furthermore, EA treatment downregulated increased c-Fos expression in brain regions, including paraventricular nucleus, rostral ventrolateral medulla, and dorsal motor nucleus of the vagus in AF, while c-Fos expression in nucleus ambiguus was upregulated with EA.

CONCLUSION

The protective effect of EA at PC6 on AF is associated with balance between sympathetic and vagal nerve activities.

Electroacupuncture for slow flow/no-reflow phenomenon in patients with acute myocardial infarction undergoing percutaneous coronary intervention: protocol for a pilot randomized controlled trial

Background

Slow flow/no-reflow (SF-NR) during percutaneous coronary intervention (PCI) is associated with poor prognosis of patients with acute myocardial infarction (AMI). Currently, effective treatment is not available for SF-NR. Electroacupuncture (EA) has shown significant efficacy as an adjuvant therapy for many cardiovascular diseases by improving microcirculation and reducing ischemia-reperfusion injury. However, its effects on SF-NR in the AMI patients during PCI are not clear. This pilot trial aims to determine the efficacy of intraoperative EA in alleviating SF-NR in AMI patients undergoing PCI.

Methods

This prospective, single-center, randomized controlled, pilot trial will recruit 60 AMI patients scheduled for PCI at the Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, China. The patients will be randomized in a 1:1 ratio into the EA or the control groups. Patients in the control group will undergo standard PCI. Patients in the EA group will undergo intraoperative electroacupuncture while undergoing standard PCI. Incidence of SF-NR is the primary outcome for this study. This study will also assess secondary outcomes including cardiac biomarkers, inflammatory biomarkers, pain and anxiety scores, electrocardiography parameters, traditional Chinese medicine (TCM) symptom score, and major adverse cardiovascular and cerebrovascular events (MACCE). All the included patients will undergo laboratory tests including routine blood tests, levels of electrolytes, as well as liver and renal function tests. Patients will be followed up for 1 month after the procedure.

Discussion

This pilot trial will provide evidence for the potential benefits of intraoperative EA in improving microvascular perfusion and preventing or alleviating SF-NR during PCI in patients with AMI. If proven effective, intraoperative EA will provide a new and effective strategy against SF-NR and provide evidence for subsequent multicenter trials.

Clinical Trial Registration

ClinicalTrials.gov, identifier (ChiCTR2300072265). Registered on 8 June 2023.

Efficacy of electroacupuncture on myocardial protection and postoperative rehabilitation in patients undergoing cardiac surgery with cardiopulmonary bypass: a systematic review and Meta-analysis

OBJECTIVE

To evaluate the efficacy of electroacupuncture (EA) intervention on myocardial protection and postoperative rehabilitation in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

Eight databases, including PubMed, Embase, the Cochrane Library, Web of Science, Chinese BioMedical Literature Database, China National Knowledge Infrastructure Database, Wanfang Data, China Science and Technology Journal Database, and two clinical trial registries, were searched. All randomized controlled trials (RCTs) related to EA intervention in cardiac surgery with CPB were collected. Based on the inclusion and exclusion criteria, two researchers independently screened articles and extracted data. After the quality evaluation, RevMan 5.3 software was used for analysis.

RESULTS

Fourteen RCTs involving 836 patients were included. Compared with the control treatment, EA significantly increased the incidence of cardiac automatic rebeat after aortic unclamping [relative risk (RR) = 1.15, 95% confidence interval (CI) (1.01, 1.31), P < 0.05; moderate]. Twenty-four hours after aortic unclamping, EA significantly increased the superoxide dismutase [standardized mean difference (SMD) = 0.96, 95% CI(0.32, 1.61), P < 0.05; low], and interleukin (IL)-2 [SMD = 1.33, 95% CI(0.19, 2.47), P < 0.05; very low] expression levels and decreased the malondialdehyde [SMD =－1.62, 95% CI(－2.15, －1.09), P < 0.05; moderate], tumour necrosis factor-α [SMD = －1.28, 95% CI(－2.37, －0.19), P < 0.05; moderate], and cardiac troponin I [SMD = －1.09, 95% CI(－1.85, －0.32), P < 0.05; low] expression levels as well as the inotrope scores [SMD = －0.77, 95% CI(－1.22, －0.31), P < 0.05; high]. There was no difference in IL-6 and IL-10 expression levels. The amount of intraoperative sedative [SMD = -0.31, 95% CI(－0.54, －0.09), P < 0.05; moderate] and opioid analgesic [SMD = -0.96, 95% CI(－1.53, －0.38), P < 0.05; low] medication was significantly lower in the EA group than in the control group. Moreover, the postoperative tracheal intubation time [SMD = －0.92, 95% CI(－1.40, －0.45), P < 0.05; low] and intensive care unit stay [SMD = －1.71, 95% CI(－3.06, －0.36), P < 0.05; low] were significantly shorter in the EA group than in the control group. There were no differences in the time to get out of bed for the first time, total days of antibiotic use after surgery, or postoperative hospital stay. No adverse reactions related to EA were reported in any of the included studies.

CONCLUSIONS

In cardiac surgery with CPB, EA may be a safe and effective strategy to reduce myocardial ischaemia-reperfusion injury and speed up the recovery of patients after surgery. These findings must be interpreted with caution, as most of the evidence was of low or moderate quality. More RCTs with larger sample sizes and higher quality are needed to provide more convincing evidence.

Electroacupuncture reduces cerebral ischemia-induced neuronal damage in the hippocampal CA1 region in rats by inhibiting HMGB1 and p-JNK overexpression

BACKGROUND

The cornu ammonis 1 (CA1) region of the hippocampus is a sensitive area that is susceptible to injury caused by cerebral ischemia. High-mobility group box 1 (HMGB1) and phosphorylated c-Jun N-terminal kinase (p-JNK) play important roles in mediating cerebral ischemic injury.

OBJECTIVE

To elucidate the mechanism through which electroacupuncture (EA) via the Baihui (GV20) and Zusanli (ST36) acupoints protects neurons.

METHODS

A rat model of permanent middle cerebral artery occlusion (pMCAO) was established. Sprague-Dawley rats were divided into four groups: sham-operated control, pMCAO control, EA, and sham-EA (SEA). In the EA and SEA groups, the GV20 and ST36 acupoints were selected for treatment. However, the SEA group was treated only by superficial pricking of the skin at the two acupoints without the application of electricity. Neurological function was assessed using the neurological deficit function score, and neuronal damage was detected through Nissl staining. HMGB1 and p-JNK expression was evaluated using immunohistochemical staining and western blot assays.

RESULTS

The behavioural experiments showed that the EA treatment improved the neurological deficits in the pMCAO rats. The Nissl staining results revealed that EA reduced neural tissue damage. The immunohistochemical staining and western blot results showed that EA inhibited HMGB1 and p-JNK overexpression. By contrast, none of these EA effects were observed in the SEA group.

CONCLUSION

EA may reduce ischemia-induced neuronal damage in the hippocampal CA1 region by inhibiting the overexpression of both HMGB1 and p-JNK.

Exploration of the Pharmacological Mechanism of Bufei Nashen Pill in Treating Chronic Obstructive Pulmonary Disease Using Network Pharmacology Integrated Molecular Docking

Objective: Based on network pharmacological analysis and molecular docking verification, the therapeutic mechanism of Bufei Nashen Pill (BFNSP) in treating chronic obstructive pulmonary disease (COPD) is discussed. Methods: First, the active ingredients and therapeutic targets of BFNSP were determined based on literature and the Chinese medicine system pharmacology database. Relevant targets of COPD were determined using GeneCard, Therapeutic Target Database and Online Mendelian Inheritance in Man (OMIM). The con-targets of BFNSP and COPD were then obtained through the Veen platform, which were implemented in Cytoscape to build “Drug-Ingredients-Potential Target network.” Target gene function enrichment analysis and signal pathway analysis were performed based on STRING database, Database for Annotation, Visualization, and Integrated Discovery, and Kyoto Encyclopedia of Genes and Genomes Pathway database. Finally, SYBYL 2.2.1 software was used to finish docking. Results: In the Drug-Ingredients-Potential Targets network, 172 active ingredients and 183 potential targets were found. Enrichment analysis showed that potential targets mainly involve biological functions such as inflammation, reactive oxygen, and immunity. Molecular docking showed that the active ingredients of BFNSP had preferential interaction with interleukin 6, mitogen-activated protein kinase 1, SRC, epidermal growth factor receptor, and matrix metalloproteinase-9. Conclusion: BFNSP can be used to treat COPD by the regulation of inflammation, immunity, and hypoxia tolerance.

STAT3 but Not STAT5 Contributes to the Protective Effect of Electroacupuncture Against Myocardial Ischemia/Reperfusion Injury in Mice

Electroacupuncture (EA) can help reduce infarct size and injury resulting from myocardial ischemia/reperfusion (I/R); however, the underlying molecular mechanism remains unknown. We previously reported that STAT5 plays a critical role in the cardioprotective effect of remote ischemic preconditioning (RIPC). Here, we assessed the effects of electroacupuncture pretreatment (EAP) on myocardial I/R injury in the presence and/or absence of Stat5 in mice and investigated whether EAP exerts its cardioprotective effects in a STAT5-dependent manner. Adult Stat5^fl/fl and Stat5-cKO mice were exposed to EAP at Neiguan (PC6) for 7 days before the induction of I/R injury by left anterior descending (LAD) coronary artery ligation. The myocardial infarct size (IS), area at risk, and apoptotic rate of cardiomyocytes were detected. RT-qPCR and western blotting were used to measure gene and protein expression, respectively, in homogenized heart tissues. RNA-seq was used to identify candidate genes and pathways. Our results showed that EAP decreased IS and the rate of cardiomyocyte apoptosis. We further found that STAT5 was activated by EAP in Stat5^fl/fl mice but not in Stat5-cKO mice, whereas the opposite was observed for STAT3. Following EAP, the levels of the antiapoptotic proteins Bcl-xL, Bcl-2, and p-AKT were increased in the presence of Stat5, while that of interleukin 10 (IL-10) was increased in both Stat5^fl/fl and Stat5-cKO. The gene expression profile in heart tissues was different between Stat5^fl/fl and the Stat5-cKO mice with EAP. Importantly, the top 30 DEGs under EAP in the Stat5-cKO mice were enriched in the IL-6/STAT3 signaling pathway. Our results revealed for the first time that the protective effect of EAP following myocardial I/R injury was attributable to, but not dependent on, STAT5. Additionally, we found that EAP could activate STAT3 signaling in the absence of the Stat5 gene, and could also activate antiapoptotic, survival, and anti-inflammatory signaling pathways.

Proteomics Analysis of the Spinal Dorsal Horn in Diabetic Painful Neuropathy Rats With Electroacupuncture Treatment

BACKGROUND

Clinical evidence demonstrates that electro-acupuncture (EA) of the Zu sanli (ST36) and Shen shu (BL23) acupoints is effective in relieving diabetic painful neuropathy (DPN); however, the underlying molecular mechanism requires further investigation, including the protein molecules associated with EA's effects on DPN.

METHODS

Sprague-Dawley adult male rats (n =36) were randomly assigned into control, DPN, and EA groups (n=12 each). After four weeks of EA treatment, response to mechanical pain and fasting blood glucose were analyzed. A tandem mass tag (TMT) labeling approach coupled with liquid chromatography with tandem mass spectrometry was used to identify potential biomarkers in the spinal dorsal horn. Further, proteomics analysis was used to quantify differentially expressed proteins (DEPs), and gene ontology, KEGG pathways, cluster, and string protein network interaction analyses conducted to explore the main protein targets of EA.

RESULTS

Compared with the DPN model group, the mechanical pain threshold was significantly increased, while the fasting blood glucose levels were clearly decreased in EA group rats. Proteomics analysis was used to quantify 5393 proteins, and DEPs were chosen for further analyses, based on a threshold of 1.2-fold difference in expression level (P < 0.05) compared with control groups. Relative to the control group, 169 down-regulated and 474 up-regulated proteins were identified in the DPN group, while 107 and 328 proteins were up- and down-regulated in the EA treatment group compared with the DPN group. Bioinformatics analysis suggested that levels of proteins involved in oxidative stress injury regulation were dramatically altered during the EA effects on DPN.

CONCLUSIONS

Our results provide the valuable protein biomarkers, which facilitates unique mechanistic insights into the DPN pathogenesis and EA analgesic, antioxidant stress and hypoglycemic effect.

Epigenetic Mechanisms of Angiogenesis in the Ischemic Heart Diseases with Acupuncture Treatment

Objective: Epigenetics, including DNA methylation, histone modification, and posttranscriptional regulation of microRNAs, is the study of heritable changes in gene expression that do not include DNA-sequence alterations. Epigenetics has become a new strategy for basic and clinical research on acupuncture in the last decade. The aim of this research update was to summarize the epigenetic mechanisms of angiogenesis induced by acupuncture treatment in ischemic heart diseases. Materials and Methods: The current authors' group has been working to illustrate the mechanism of acupuncture from an epigenetics perspective, which has shed new lights on the mechanisms and applications of acupuncture in cardiovascular diseases. This article summarizes the group's new findings in animal models as well as in patients with chronic stable angina. Progress since 2011 in other teams' research in this field is also discussed in this article. Conclusions: Acupuncture could regulate histone modifications and could rescue patients who sustain ischemic injuries. This treatment could possibly work through promoting angiogenesis.

Jiaji (EX-B2)-Based Electroacupuncture Preconditioning Attenuates Early Ischaemia Reperfusion Injury in the Rat Myocardium

Background

Acupuncture preconditioning was able to reduce the extent of ischaemia reperfusion (I/R) injury. Previous studies have shown that electroacupuncture (EA) pretreatment at T4-T5 Jiaji (EX-B2) acupoints had cardioprotective effects against myocardial I/R injury. However, the molecular mechanism remains inconclusive.

Methods

Wistar rats were pretreated with electroacupuncture for 7 days at the Neiguan (PC6), T4-T5 Jiaji (EX-B2), Yanglingquan (GB34), and Quchi (LI11) acupoints, which belong to different meridians. Then, we investigated the genome-wide gene expression profiles of rats prestimulated at these acupoints after I/R injury.

Results

Our study revealed previously unknown cardioprotective roles of T4-T5 Jiaji (EX-B2) acupoints in the I/R progression. The extent of myocardial injury was significantly decreased in the Jiaji group compared with the I/R group. In addition, our data are among the first to link the EA preconditioning at Neiguan (PC6) acupoints and circadian rhythm in the I/R model. Also, for the first time, we explored the meridian and acupoint specificity involved in EA pretreatment at the heart meridian, in which Yanglingquan and Quchi acupoints were selected as the control group for heart-divergent-meridian and nonheart-meridian acupoints.

Conclusions

The present study suggested that EA pretreatment at Jiaji alters genome-wide gene expression and protects the rat myocardium against I/R injury, which are most likely through neurohumoral regulation.

Acupuncture Reduces Hypertrophy and Cardiac Fibrosis, and Improves Heart Function in Mice with Diabetic Cardiomyopathy

PURPOSE

To assess the effects of electro-acupuncture (EA) on glycemic control, myocardial inflammation, and the progression of diabetic cardiomyopathy in mice with type 2 diabetes.

METHODS

Db/Db mice received EA at PC6+ST36 (DM-Acu), non-acupoint simulation (DM-Sham), or no treatment (DM). EA was applied for 30 min per day, 5 days a week for 4 weeks. Heart function was assessed by echocardiography. Myocardium was assessed by RT-PCR, immunoblotting, and histology. Serum TNF-α, IL-1α, IL-1β, IL-6, and IL-8 were measured.

RESULTS

DM-Acu, but not DM-Sham, reduced fasting blood glucose without affecting body weight. DM decreased systolic function. DM-Acu, but not DM-Sham, attenuated the decrease in systolic function. Heart weight was significantly smaller in the DM-Acu than in the DM and DM-Sham groups. Percent fibrosis and apoptosis were reduced in the DM-Acu, but not the DM-Sham, group. Serum levels of IL-1α, IL-1β, IL-6, IL-8, ICAM-1, MCP-1, and TNF-α were significantly lower in the DM-Acu than in the DM or DM-Sham groups. Protein levels of P-Akt and P-AMPK and mRNA levels of phosphoinositide-3-kinase regulatory subunit 6 (PIK3r6) were significantly higher in the DM-Acu group. Myocardial mRNA and protein levels of insulin-like growth factor 1 receptor (IGF1R) were significantly lower in the DM and DM-Sham groups compared with the DM-Acu group.

CONCLUSIONS

EA reduced serum glucose; prevented DM-induced hypertrophy and deterioration of systolic function, inflammation, and fibrosis; and restored IGF1R, P-Akt, and P-AMPK levels in mice with type 2 diabetes mellitus.

Electroacupuncture pretreatment alleviates myocardial injury through regulating mitochondrial function

Background

Electroacupuncture is well known for its advantageous neuroanalgesic and therapeutic effects on myocardial ischemia–reperfusion injury. The purpose of the present research was to verify whether electroacupuncture can alleviate bupivacaine-induced myocardial injury.

Methods

Specific pathogen-free Wistar rats were used to establish the bupivacaine-induced myocardial injury model. Western blot, PCR, transmission electron microscope and enzyme-linked immunosorbent (ELISA) methods were used to evaluate bupivacaine-induced structure injury and dysfunction of the mitochondria as well as the alleviating effects of lipid emulsion, acupoint injection, and electroacupuncture pre-treatment of the oxidase stress response.

Results

Bupivacaine caused structural damage, degradation, and swelling of mitochondria. Furthermore, it reduced adenosine triphosphate (ATP) synthesis and impaired energy metabolism in the mitochondria. Structural and functional impairment of the mitochondria was alleviated via lipid emulsion injection, acupoint injection, and electroacupuncture pre-treatment. Electroacupuncture pre-treatment of PC6 yielded a greater alleviating effect than others approaches. Following electroacupuncture pre-treatment of PC6 point, the number of mitochondria increased; apoptosis was reduced, enzymatic activity of cytochrome C oxidase (COX) and superoxide dismutase and expression of uncoupling protein 2, voltage-dependent anion channel 1, and Bcl 2 were upregulated and SLC25A6, MDA levels were downregulated. Additionally, our findings indicated that electroacupuncture pre-treatment of PC6 point exerted an effect on the mitochondria via the mitochondrial-transcription-factor-A/nuclear-respiratory-factor-1/proliferator-activated-receptor-gamma-coactivator-1 pathway.

Conclusion

The present study revealed that electroacupuncture pre-treatment of PC6 could effectively alleviate bupivacaine-induced myocardial mitochondrial damage, thereby providing a theoretical basis for clinical studies and applications of this treatment method.

Electroacupuncture preconditioning attenuates acute myocardial ischemia injury through inhibiting NLRP3 inflammasome activation in mice

AIMS

Electro-acupuncture pretreatment (EAP) plays a protective role in myocardial ischemia (MI) injury. However, the underlying mechanism remains unclear. A growing body of evidence suggests postinfarction inflammatory response directly affects the remodeling of ventricular function. The purpose of this study was to investigate whether EAP alleviates MI through NLRP3 inflammasome inhibition.

MATERIALS AND METHODS

We constructed an AMI model by ligating the left anterior descending (LAD) coronary artery after 3 days of EAP with C57BL/6 mice. Echocardiography and TTC staining were employed to evaluate cardiac function and infarct size after 24 h of ischemia. HE staining and immunohistochemistry were employed to determine inflammatory level. Then, inflammasome activation was detected by western blotting, and macrophage polarization and neutrophil infiltration were observed by flow cytometry.

KEY FINDINGS

Our preliminary findings showed that EAP reduced the infarct area and increased fractional shortening (FS) and ejection fraction (EF) and decreased the degree of inflammation after AMI injury. Meanwhile, EAP inhibited the expression of NLRP3, cleaved caspase-1 and IL-1β in ischemia myocardial tissue, companied by inhibiting the expression of F4/80⁺, CD11b⁺, CD206^low macrophages and activated M2 macrophage, and decreasing Ly-6G⁺CD11b⁺ neutrophils in ischemia myocardial and spleen tissue.

SIGNIFICANCE

EAP inhibits the activation of NLRP3 inflammasome, promotes M2 polarization of macrophages and reduces the recruitment of neutrophils in damaged myocardium, thereby decreases the infarct size and improves the cardiac function.

Cardioprotective effect of electroacupuncture in cardiopulmonary bypass through apelin/APJ signaling

Aim Acupuncture, particularly electroacupuncture (EA), can improve the clinical outcomes of cardiopulmonary bypass (CPB) patients; however, the mechanisms remain unclear. This study aimed to examine the effects of EA pre-treatment on myocardial injury after CPB and investigate its potential mechanisms.

MAIN METHODS

Male Sprague-Dawley rats were subjected to CPB and divided into Control (sham-operated), CPB, and EA (CPB + EA) groups. In the EA group, rats were treated with EA at the "PC6" acupoint for 30 min before being subjected to CPB. At 0.5, 1, and 2 h after CPB, the expression levels of plasma cardiac troponin I (cTnI) and lactate dehydrogenase (LDH), and myeloperoxidase (MPO) activity, TNFα, IL-1β, reduced glutathione (GSH), oxidized glutathione (GSSH), and the ratio of GSH/GSSH in the myocardial tissue were measured. Apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining. The expression of cleaved caspase-3 was detected by immunofluorescence. The expression of apelin, APJ, AKT, p-Akt, ERK1/2, and p-ERK1/2 was determined using western blotting.

KEY FINDINGS

Decreased myocardial injury marker levels, myocardial apoptosis, oxidative stress, and the inflammatory response were found in the EA group compared with the CPB group. The expression levels of apelin, APJ, and p-Akt/AKT were increased in the EA group, and the p-ERK1/2/ERK1/2 level was decreased.

SIGNIFICANCE

This study showed that EA pre-treatment can protect the heart from damage following CPB, which might be mainly mediated by restoring the apelin/APJ signaling pathway.

Electroacupuncture Alleviates Ischemic Brain Injury by Inhibiting the miR-223/NLRP3 Pathway

Background

Electroacupuncture (EA) has been commonly used to treat stroke in China. However, the underlying mechanism remains largely unknown. The present study investigated the neuroprotective effects of EA in middle cerebral artery occlusion (MCAO) rats and elucidated the possible anti-inflammatory mechanisms.

Material/Methods

In this study, modified neurological severity scoring (mNSS) was used to assess neurological deficits, and TTC staining and brain water content were measured to evaluate the degree of brain damage. HE staining, Nissl staining, and TUNEL staining were employed to evaluate apoptotic neuronal death. Molecular biological methods were used to measure the levels of miR-233, NLRP3, caspase-1, IL-1β, and IL-18 in the peri-infarct cortex.

Results

Our results showed that EA treatment significantly decreased the neurological deficit score and infarct volume of MCAO rats. The level of miR-223 was increased, while the levels of NLRP3, caspase-1, IL-1β, and IL-18 were decreased in the peri-infarct cortex of EA-treated MCAO rats. However, the neuroprotective effect of EA was partially blocked by antagomir-223.

Conclusions

These data suggest that EA treatment can alleviate neuroinflammation by inhibiting the miR-223/NLRP3 pathway, thus playing a neuroprotective role in MCAO in rats.

miR-146a-5p Mediates Intermittent Hypoxia-Induced Injury in H9c2 Cells by Targeting XIAP

MicroRNAs (miRNAs) have emerged as key modulators in the pathophysiologic processes of cardiovascular diseases. However, its function in cardiac injury induced by obstructive sleep apnea (OSA) remains unknown. The aim of the current study was to identify the effect and potential molecular mechanism of miR-146a-5p in intermittent hypoxia(IH)- induced myocardial damage. We exposed H9c2 cells to IH condition; the expression levels of miR-146a-5p were detected by RT-qPCR. Cell viability, cell apoptosis, and the expressions of apoptosis-associated proteins were assessed via Cell Counting Kit-8 (CCK-8), flow cytometry, and western blotting, respectively. Target genes of miR-146a-5p were confirmed by dual-luciferase reporter assay. IH remarkably lowered viability but enhanced cell apoptosis. Concomitantly, the miR-146a-5p expression level was increased in H9c2 cells after IH. Subsequent experiments showed that IH-induced injury was alleviated through miR-146a-5p silence. X-linked inhibitor of apoptosis protein (XIAP) was predicted by bioinformatics analysis and further confirmed as a direct target gene of miR-146a-5p. Surprisingly, the effect of miR-146a-5p inhibition under IH may be reversed by downregulating XIAP expression. In conclusion, our results demonstrated that miR-146a-5p could attenuate viability and promote the apoptosis of H9c2 by targeting XIAP, thus aggravating the H9c2 cell injury induced by IH, which could enhance our understanding of the mechanisms for OSA-associated cardiac injury.

Analyses of changes in myocardial long non-coding RNA and mRNA profiles after severe hemorrhagic shock and resuscitation via RNA sequencing in a rat model

Background

Ischemia–reperfusion injury has been proven to induce organ dysfunction and death, although the mechanism is not fully understood. Long non-coding RNAs (lncRNAs) have drawn wide attention with their important roles in the gene expression of some biological processes and diseases, including myocardial ischemia–reperfusion (I/R) injury. In this paper, a total of 26 Sprague–Dawley (SD) rats were randomized into two groups: sham and ischemia–reperfusion (I/R) injury. Hemorrhagic shock was induced by removing 45% of the estimated total blood volume followed by reinfusion of shed blood. High-throughput RNA sequencing was used to analyze differentially expressed (DE) lncRNAs and messenger RNAs (mRNAs) in the heart tissue 4 h after reperfusion. Myocardial function was also evaluated.

Results

After resuscitation, the decline of myocardial function of shocked animals, expressed by cardiac output, ejection fraction, and myocardial performance index (MPI), was significant (p < 0.05). DE lncRNAs and mRNAs were identified by absolute value of fold change ≥ 2 and the false discovery rate ≤ 0.001. In rats from the I/R injury group, 851 lncRNAs and 1015 mRNAs were significantly up-regulated while 1533 lncRNAs and 1702 m RNAs were significantly down-regulated when compared to the sham group. Among the DE lncRNAs, we found 12 location-associated with some known apoptosis-related protein-coding genes which were up-regulated or down-regulated accordingly, including STAT3 and Il1r1. Real time PCR assays confirmed that the expression levels of five location-associated lncRNAs (NONRATT006032.2, NONRATT006033.2, NONRATT006034.2, NONRATT006035.2 and NONRATT029969.2) and their location-associated mRNAs (STAT3 and Il1r1) in the rats from the I/R injury group were all significantly up-regulated versus the sham group.

Conclusions

The DE lncRNAs (NONRATT006032.2, NONRATT006033.2, NONRATT006034.2 and NONRATT006035.2) could be compatible with their role in myocardial protection by stimulating their co-located gene (STAT3) after hemorrhagic shock and resuscitation. The final prognosis of I/R injury might be regulated by different genes, which is regarded as a complex network.

Electronic supplementary material

The online version of this article (10.1186/s12867-018-0113-8) contains supplementary material, which is available to authorized users.

Schisandrin B Ameliorates Myocardial Ischemia/Reperfusion Injury Through Attenuation of Endoplasmic Reticulum Stress-Induced Apoptosis

Schisandrin B (Sch B), an active composition isolated from the fruit of Schisandra chinensis, has been proved to possess antiinflammatory, antioxidant and anti-endoplasmic reticulum (ER) stress effects in many rodent tissues. However, the exact mechanism of cardioprotective effect of Sch B still needs more study. Here, we detected the effects of Sch B on myocardial ischemia/reperfusion (I/R) injury rats. I/R injury model in this study was established by left anterior descending coronary artery ligation for 40 min followed by 1 h of reperfusion. Male healthy rats were randomly divided into five groups: the sham, I/R, Sch B (20 mg/kg) + I/R, and Sch B (40 mg/kg) + I/R, Sch B (80 mg/kg) + I/R, with 10 rats in each group. We showed that Sch B treatment significantly protected against myocardial I/R injury, as demonstrated by the decrease in the percentage of infarct formation assessed by 2,3,5-triphenyl tetrazolium chloride (TTC) staining in representative heart tissue slices, comparing with the I/R control group. The levels of creatine kinase (CK), lactate dehydrogenase (LDH), malondialdehyde (MDA), and total superoxide dismutase (T-SOD) were tested. The ER stress-related proteins such as C/EBP homologous protein (CHOP), activating transcription factor 6 (ATF6), and (PKR)-like ER kinase (PERK) were further measured by western blot, and their messenger RNA levels were measured by real-time PCR. The apoptosis of heart tissue cells was also tested through the expressions of caspase-9, caspase-3, Bcl-2, and Bax proteins. Collectively, these results revealed that Sch B exerts protection role on myocardial I/R injury through decreasing oxidative reaction, suppressing ATF6 and PERK pathway, and attenuating ER stress-induced apoptosis.

CCAAT/enhancer binding protein homologous protein knockdown alleviates hypoxia-induced myocardial injury in rat cardiomyocytes exposed to high glucose

Diabetic patients are more sensitive to ischemic injury than non-diabetics. Endoplasmic reticulum (ER) stress has been reported to be closely associated with the pathophysiology of ischemic injury in diabetes. The aim of the present study was to investigate the mechanisms involved in the progression of diabetes complicated by myocardial infarction (MI) and further verify the role of CCAAT/enhancer binding protein (C/EBP)-homologous protein (CHOP) using an in vitro model of diabetes/MI. The rats were exposed to 65 mg/kg streptozotocin (STZ) and left anterior descending (LAD) coronary artery ligation. ST-segment elevation, heart rate, left ventricular systolic pressure (LVSP) and LV end-diastolic pressure (LVEDP) were measured. Serum creatinine kinase-MB (CK-MB) and cardiac troponin T (cTnT) levels were examined by ELISA. Infarct size and apoptosis were measured by triphenyltetrazolium chloride staining and terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assay. Pathological changes were evaluated by hematoxylin and eosin staining. H9c2 cells were used to establish an in vitro model of diabetes complicated by MI. Following CHOP knockdown, cell viability, cell cycle distribution and apoptosis were examined by Cell Counting Kit-8 assay, flow cytometry and Hoechst staining. Glucose-regulated protein 78 (GRP78), CHOP, B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), endoplasmic reticulum oxidoreductase 1 (Ero1)-α, Ero1β and protein disulfide isomerase (PDI) levels in both myocardial tissues and H9c2 cells were determined by western blotting. In the present study, diabetes complicated by MI promoted ST-segment elevation and myocardial apoptosis, increased infarct size, induced pathological changes and elevated LVEDP, CK-MB, cTnT, GRP78, CHOP, Bax, Ero1α, Ero1β and PDI; however, it decreased heart rate, LVSP and Bcl-2. Additionally, high glucose combined with hypoxic treatment reduced cell viability, induced cell cycle arrest at G1 phase, promoted cell apoptosis, and activated the GRP78/CHOP and Ero1/PDI signaling pathways, which were reversed by CHOP knockdown. Thus, CHOP may be an effective therapeutic target for the treatment of diabetes complicated by MI.

Ginsenoside Rg3 Improves Cardiac Function after Myocardial Ischemia/Reperfusion via Attenuating Apoptosis and Inflammation

Objectives. Ginsenoside Rg3 is one of the ginsenosides which are the main constituents isolated from Panax ginseng. Previous study demonstrated that ginsenoside Rg3 had a protective effect against myocardial ischemia/reperfusion- (I/R-) induced injury. Objective. This study was designed to evaluate the effect of ginsenoside Rg3 on cardiac function impairment induced by myocardial I/R in rats. Methods. Sprague-Dawley rats were subjected to myocardial I/R. Echocardiographic and hemodynamic parameters and histopathological examination were carried out. The expressions of P53, Bcl-2, Bax, and cleaved caspase-3 and the levels of TNF-α and IL-1β in the left ventricles were measured. Results. Ginsenoside Rg3 increased a left ventricular fractional shortening and left ventricular ejection fraction. Treatment with ginsenoside Rg3 also alleviated increases of left ventricular end diastolic pressure and decreases of left ventricular systolic pressure and ±dp/dt in myocardial I/R-rats. Ginsenoside Rg3 decreased apoptosis cells through inhibiting the activation of caspase-3. Ginsenoside Rg3 also caused significant reductions of the contents of TNF-α and IL-1β in left ventricles of myocardial I/R-rats. Conclusion. The findings suggested that ginsenoside Rg3 possessed the effect of improving myocardial I/R-induced cardiac function impairment and that the mechanism of pharmacological action of ginsenoside Rg3 was related to its properties of antiapoptosis and anti-inflammation.

Vildagliptin reduces cardiac ischemic-reperfusion injury in obese orchiectomized rats

Obesity and testosterone deprivation are associated with coronary artery disease. Testosterone and vildagliptin (dipeptidyl peptidase-4 inhibitors) exert cardioprotection during ischemic-reperfusion (I/R) injury. However, the effect of these drugs on I/R heart in a testosterone-deprived, obese, insulin-resistant model is unclear. This study investigated the effects of testosterone and vildagliptin on cardiac function, arrhythmias and the infarct size in I/R heart of testosterone-deprived rats with obese insulin resistance. Orchiectomized (O) or sham operated (S) male Wistar rats were divided into 2 groups to receive normal diet (ND) or high-fat diet (HFD) for 12 weeks. Orchiectomized rats in each diet were divided to receive testosterone (2 mg/kg), vildagliptin (3 mg/kg) or the vehicle daily for 4 weeks. Then, I/R was performed by a 30-min left anterior descending coronary artery ligation, followed by a 120-min reperfusion. LV function, arrhythmia scores, infarct size and cardiac mitochondrial function were determined. HFD groups developed insulin resistance at week 12. At week 16, cardiac function was impaired in NDO, HFO and HFS rats, but was restored in all testosterone- and vildagliptin-treated rats. During I/R injury, arrhythmia scores, infarct size and cardiac mitochondrial dysfunction were prominently increased in NDO, HFO and HFS rats, compared with those in NDS rats. Treatment with either testosterone or vildagliptin similarly attenuated these impairments during I/R injury. These finding suggest that both testosterone replacement and vildagliptin share similar efficacy for cardioprotection during I/R injury by decreasing the infarct size and attenuating cardiac mitochondrial dysfunction caused by I/R injury in testosterone-deprived rats with obese insulin resistance.