BACKGROUND: Dysfunction of the gap junction channel protein connexin 43 (Cx43) contributes to myocardial ischemia/reperfusion (I/R)-induced ventricular arrhythmias. Cx43 can be regulated by small ubiquitin-like modifier (SUMO) modification. Protein inhibitor of activated STAT Y (PIASy) is an E3 SUMO ligase for its target proteins. However, whether Cx43 is a target protein of PIASy and whether Cx43 SUMOylation plays a role in I/R-induced arrhythmias are largely unknown. METHODS: Male Sprague-Dawley rats were infected with PIASy short hairpin ribonucleic acid (shRNA) using recombinant adeno-associated virus subtype 9 (rAAV9). Two weeks later, the rats were subjected to 45 min of left coronary artery occlusion followed by 2 h reperfusion. Electrocardiogram was recorded to assess arrhythmias. Rat ventricular tissues were collected for molecular biological measurements. RESULTS: Following 45 min of ischemia, QRS duration and QTc intervals statistically significantly increased, but these values decreased after transfecting PIASy shRNA. PIASy downregulation ameliorated ventricular arrhythmias induced by myocardial I/R, as evidenced by the decreased incidence of ventricular tachycardia and ventricular fibrillation, and reduced arrythmia score. In addition, myocardial I/R statistically significantly induced PIASy expression and Cx43 SUMOylation, accompanied by reduced Cx43 phosphorylation and plakophilin 2 (PKP2) expression. Moreover, PIASy downregulation remarkably reduced Cx43 SUMOylation, accompanied by increased Cx43 phosphorylation and PKP2 expression after I/R. CONCLUSION PIASy downregulation inhibited Cx43 SUMOylation and increased PKP2 expression, thereby improving ventricular arrhythmias in ischemic/reperfused rats heart.
Rats ; Male ; Animals ; Myocardial Reperfusion Injury/metabolism* ; Connexin 43/genetics* ; Sumoylation ; Down-Regulation ; Rats, Sprague-Dawley ; Arrhythmias, Cardiac/drug therapy* ; Myocardial Ischemia/metabolism* ; RNA, Small Interfering/metabolism*

This study aimed to investigate the effect and underlying mechanism of Poria cocos polysaccharides(PCP) on myocardial cell apoptosis in the rat model of myocardial ischemia-reperfusion injury(MI/RI). Male SPF-grade SD rats were randomly divided into a sham group(saline), a model group(saline), low-and high-dose PCP groups(100 and 200 mg·kg~(-1)), and a fasudil group(10 mg·kg~(-1)), with 16 rats in each group. Except for the sham group, the other four groups underwent left anterior descending coronary artery ligation for 30 min followed by reperfusion for 2 h to establish the MI/RI model. The myocardial infarct area was assessed by TTC staining. Histological changes were observed through HE staining. Myocardial cell apoptosis was evaluated using TUNEL staining. Serum lactate dehydrogenase(LDH), creatine kinase MB(CK-MB), interleukin-1β(IL-1β) and IL-18 levels, myocardial superoxide dismutase(SOD) activity and malondialdehyde(MDA) levels were detected by ELISA. Protein expression of B-cell lymphoma 2(Bcl-2), Bcl-2 associated X protein(Bax), cleaved caspase-3, Ras homolog gene A(RhoA), myosin phosphatase target subunit 1(MYPT-1), phosphorylated MYPT-1(p-MYPT-1), and Rho-associated coiled-coil forming kinase 1(ROCK 1) were measured by Western blot. Pathological staining of myocardial tissue revealed that in the model group, there was focal necrosis of myocardial tissue, myocardial cell swelling, unclear boundaries, and neutrophil infiltration. These pathological changes were alleviated in the low-and high-dose PCP groups and the fasudil group. Compared with the model group, the low-and high-dose PCP groups and the fasudil group showed significantly reduced myocardial infarct area and myocardial cell apoptosis rate. Compared with the sham group, the model group exhibited elevated serum LDH, CK-MB, IL-1β and IL-18 levels, increased MDA levels, relative protein expression of Bax, cleaved caspase-3, RhoA, ROCK1 and p-MYPT-1, and decreased myocardial SOD levels and Bcl-2 protein expression. Compared with the model group, the PCP groups and the fasudil group showed lowered serum LDH, CK-MB, IL-1β and IL-18 levels, decreased MDA levels, relative protein expression of Bax, cleaved caspase-3, RhoA, ROCK1 and p-MYPT-1, and increased myocardial SOD levels and Bcl-2 protein expression. PCP exhibited a certain preventive effect on myocardial tissue pathological damage and myocardial cell apoptosis in MI/RI rats, possibly related to the inhibition of the Rho-ROCK signaling pathway activation, thereby reducing oxidative stress and inflammatory responses.
Rats ; Male ; Animals ; Myocardial Reperfusion Injury/drug therapy* ; bcl-2-Associated X Protein/metabolism* ; Rats, Sprague-Dawley ; Caspase 3/metabolism* ; Interleukin-18 ; Wolfiporia ; Signal Transduction ; Myocardial Infarction/drug therapy* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Creatine Kinase, MB Form ; Apoptosis ; Polysaccharides/pharmacology* ; Superoxide Dismutase/metabolism* ; 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine/analogs & derivatives*

OBJECTIVE: To explore the protective effect of Huoxin Pill (HXP) on acute myocardial ischemia-reperfusion (MIRI) injury in rats. METHODS: 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). RESULTS: 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). CONCLUSIONS 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.
Humans ; Rats ; Animals ; NF-kappa B/metabolism* ; Myocardial Reperfusion Injury/drug therapy* ; NLR Family, Pyrin Domain-Containing 3 Protein ; Rats, Sprague-Dawley ; C-Reactive Protein ; Toll-Like Receptor 4 ; Phosphatidylinositol 3-Kinases/metabolism* ; Molecular Docking Simulation ; Signal Transduction ; Myocardial Infarction/drug therapy* ; Creatine Kinase ; L-Lactate Dehydrogenase/metabolism* ; Superoxide Dismutase/metabolism*

This study aimed to explore the mechanism of resveratrol(RES) pretreatment in improving mitochondrial function and alleviating myocardial ischemia-reperfusion(IR) injury by inhibiting stromal interaction molecule 2(STIM2) through microRNA-20 b-5 p(miR-20 b-5 p). Ninety rats were randomly assigned into sham group, IR group, IR+RES(50 mg·kg~(-1) RES) group, IR+RES+antagomir NC(50 mg·kg~(-1) RES+80 mg·kg~(-1) antagomir NC) group, and IR+RES+miR-20 b-5 p antagomir(50 mg·kg~(-1) RES+80 mg·kg~(-1) miR-20 b-5 p antagomir) group, with 18 rats/group. The IR rat model was established by ligation of the left anterior descending coronary artery. Two weeks before the operation, rats in the IR+RES group were intraperitoneally injected with 50 mg·kg~(-1) RES, and those in the sham and IR groups were injected with the same dose of normal saline, once a day. Ultrasonic instrument was used to detect the left ventricular internal diameter at end-diastole(LVIDd) and left ventricular internal diameter at end-systole(LVIDs) of rats in each group. The 2,3,5-triphenyte-trazoliumchloride(TTC) method and hematoxylin-eosin(HE) staining were employed to detect the myocardial infarction area and histopathology, respectively. Real-time quantitative PCR(qRT-PCR) was carried out to detect the expression of miR-20 b-5 p in myocardial tissue. Oxygen glucose deprivation/reoxygenation(OGD/R) was performed to establish an OGD/R model of H9 c2 cardiomyocytes. CCK-8 assay was employed to detect H9 c2 cell viability. H9 c2 cells were assigned into the control group, OGD/R group, OGD/R+RES group(25 μmol·L~(-1)), OGD/R+RES+inhibitor NC group, OGD/R+RES+miR-20 b-5 p inhibitor group, mimic NC group, miR-20 b-5 p mimic group, inhibitor NC group, and miR-20 b-5 p inhibitor group. Flow cytometry was employed to detect cell apoptosis. Western blot was employed to detect the expression of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), cleaved-cysteine proteinase 3(cleaved-caspase-3), and STIM2 in cells. The mitochondrial membrane potential(MMP) assay kit, reactive oxygen species(ROS) assay kit, and adenosine triphosphate(ATP) assay kit were used to detect the MMP, ROS, and ATP levels, respectively. Dual luciferase reporter gene assay was adopted to verify the targeting relationship between miR-20 b-5 p and STIM2. Compared with the sham group, the modeling of IR increased the myocardial infarction area, LVIDd, LVIDs, and myocardial pathology and down-regulated the expression of miR-20 b-5 p(P<0.05). These changes were alleviated in the IR+RES group(P<0.05). The IR+RES+miR-20 b-5 p antagomir group had higher myocardial infarction area, LVIDd, LVIDs, and myocardial pathology and lower expression of miR-20 b-5 p than the IR+RES group(P<0.05). The OGD/R group had lower viability of H9 c2 cells than the control group(P<0.05) and the OGD/R+RES groups(25, 50, and 100 μmol·L~(-1))(P<0.05). Additionally, the OGD/R group had higher H9 c2 cell apoptosis rate, protein levels of Bax and cleaved caspase-3, and ROS level and lower Bcl-2 protein, MMP, and ATP levels than the control group(P<0.05) and the OGD/R+RES group(P<0.05). The OGD/R+RES+miR-20 b-5 p inhibitor group had higher H9 c2 cell apoptosis rate, protein levels of Bax and cleaved-caspase 3, and ROS level and lower Bcl-2 protein, MMP, and ATP levels than the OGD/R+RES group(P<0.05). miR-20 b-5 p had a targeting relationship with STIM2. The expression of STIM2 was lower in the miR-20 b-5 p mimic group than in the mimic NC group(P<0.05) and lower in the inhibitor NC group than in the miR-20 b-5 p inhibitor group(P<0.05). RES pretreatment can inhibit the expression of STIM2 by promoting the expression of miR-20 b-5 p, thereby improving the function of mitochondria and alleviating myocardial IR damage.
Animals ; Rats ; Adenosine Triphosphate ; Antagomirs/metabolism* ; bcl-2-Associated X Protein/metabolism* ; Caspase 3/metabolism* ; Glucose/metabolism* ; MicroRNAs/metabolism* ; Mitochondria, Heart/drug effects* ; Myocardial Infarction/drug therapy* ; Myocardial Reperfusion Injury/drug therapy* ; Myocytes, Cardiac ; Oxygen/metabolism* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats, Sprague-Dawley ; Reactive Oxygen Species/metabolism* ; Resveratrol/therapeutic use* ; Stromal Interaction Molecule 2/metabolism*

OBJECTIVE: To examine the effect of Shenmai Injection (SMJ) on ferroptosis during myocardial ischemia reperfusion (I/R) injury in rats and the underlying mechanism. METHODS: A total of 120 SPF-grade adult male SD rats, weighing 220-250 g were randomly divided into different groups according to a random number table. Myocardial I/R model was established by occluding the left anterior descending artery for 30 min followed by 120 min of reperfusion. SMJ was injected intraperitoneally at the onset of 120 min of reperfusion, and erastin (an agonist of ferroptosis), ferrostatin-1 (Fer-1, an inhibitor of ferroptosis) and ML385 (an inhibitor of nuclear factor erythroid-2 related factor 2 (Nrf2)) were administered intraperitoneally separately 30 min before myocardial ischemia as different pretreatments. Cardiac function before ischemia, after ischemia and after reperfusion was analysed. Pathological changes in the myocardium and the ultrastructure of cardiomyocytes were observed, and the myocardial infarction area was measured. Additionally, the concentration of Fe²⁺ in heart tissues and the levels of creatine kinase-MB (CK-MB), troponin I (cTnl), malondialdehyde (MDA) and superoxide dismutase (SOD) in serum were measured using assay kits, and the expressions of Nrf2, glutathione peroxidase 4 (GPX4) and acyl-CoA synthetase long-chain family member 4 (ACSL4) were examined by Western blot. RESULTS: Compared with the sham group, I/R significantly injured heart tissues, as evidenced by the disordered, ruptured and oedematous myocardial fibres; the increases in infarct size, serum CK-MB, cTnI and MDA levels, and myocardial Fe²⁺ concentrations; and the decreases in SOD activity (P<0.05). These results were accompanied by ultrastructural alterations to the mitochondria, increased expression of ACSL4 and inhibited the activation of Nrf2/GPX4 signalling (P<0.05). Compared with I/R group, pretreatment with 9 mL/kg SMJ and 2 mg/kg Fer-1 significantly reduced myocardial I/R injury, Fe²⁺ concentrations and ACSL4 expression and attenuated mitochondrial impairment, while 14 mg/kg erastin exacerbated myocardial I/R injury (P<0.05). In addition, cardioprotection provided by 9 mL/kg SMJ was completely reversed by ML385, as evidenced by the increased myocardial infarct size, CK-MB, cTnI, MDA and Fe²⁺ concentrations, and the decreased SOD activity (P<0.05). CONCLUSIONS Ferroptosis is involved in myocardial I/R injury. Pretreatment with SMJ alleviated myocardial I/R injury by activating Nrf2/GPX4 signalling-mediated ferroptosis, thereby providing a strategy for the prevention and treatment of ischemic heart diseases.
Animals ; Male ; Rats ; Coenzyme A ; Creatine Kinase ; Ferroptosis ; Ligases ; Malondialdehyde ; Myocardial Infarction/drug therapy* ; Myocardial Ischemia/drug therapy* ; Myocardial Reperfusion Injury/pathology* ; Myocytes, Cardiac/metabolism* ; NF-E2-Related Factor 2/metabolism* ; Phospholipid Hydroperoxide Glutathione Peroxidase ; Rats, Sprague-Dawley ; Superoxide Dismutase/metabolism* ; Troponin I

Animals ; Apoptosis ; Bridged Bicyclo Compounds, Heterocyclic/pharmacology* ; Cell Line ; Hypoxia ; MicroRNAs/genetics* ; Myocardial Reperfusion Injury/drug therapy* ; Myocytes, Cardiac ; Oxidative Stress ; Rats ; Reperfusion Injury ; Tetrahydronaphthalenes/pharmacology*

Animals ; Male ; Medicine, Mongolian Traditional ; Myocardial Ischemia/drug therapy* ; Myocardial Reperfusion Injury ; Myocardium ; NF-kappa B ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To investigate the protective effect of melatonin against myocardial ischemia reperfusion (IR) injury in isolated rat hearts and explore the underlying mechanisms. METHODS: The isolated hearts from 40 male SD rats were randomly divided into 4 groups (=10): the control group, where the hearts were perfused with KH solution for 175 min; IR group, where the hearts were subjected to global ischemia for 45 min followed by reperfusion for 120 min; IR+melatonin (Mel+IR) group, where melatonin (5 μmol/L) was administered to the hearts 1 min before ischemia and during the first 5 min of reperfusion, followed by 115 min of reperfusion; and IR+2, 3-butanedione monoxime (IR+BDM) group, where the hearts were treated with BDM (20 mmol/L) in the same manner as melatonin treatment. Myocardial injury in the isolated hearts was assessed based on myocardial injury area, caspase-3 activity, and expressions of cytochrome C and cleaved caspase-3 proteins. Cardiac contracture was assessed using HE staining and by detecting lactate dehydrogenase (LDH) activity and the content of cardiac troponin I (cTnI) in the coronary outflow, measurement of left ventricular end-diastolic pressure (LVEDP) and electron microscopy. The content of ATP in the cardiac tissue was also determined. RESULTS: Compared with those in the control group, the isolated hearts in IR group showed significantly larger myocardial injury area and higher caspase-3 activity and the protein expressions of cytochrome C and cleaved caspase-3 with significantly increased LDH activity and cTnI content in the coronary outflow and elevated LVEDP at the end of reperfusion; HE staining showed obvious fractures of the myocardial fibers and the content of ATP was significantly decreased in the cardiac tissue; electron microscopy revealed the development of contraction bands. In the isolated hearts with IR, treatment with Mel or BDM significantly reduced the myocardial injury area, caspase-3 activity, and protein expressions of cytochrome C and cleaved caspase-3, obviously inhibited LDH activity, lowered the content of cTnI and LVEDP, reduced myocardial fiber fracture, and increased ATP content in the cardiac tissue. Both Mel and BDM inhibited the formation of contraction bands in the isolated hearts with IR injury. CONCLUSIONS Mel can alleviate myocardial IR injury in isolated rat hearts by inhibiting cardiac contracture, the mechanism of which may involve the upregulation of ATP in the cardiac myocytes to lessen the tear of membrane and reduce cell content leakage.
Animals ; Heart ; drug effects ; Male ; Melatonin ; pharmacology ; therapeutic use ; Muscle Contraction ; drug effects ; Myocardial Reperfusion Injury ; drug therapy ; Myocytes, Cardiac ; drug effects ; Rats ; Rats, Sprague-Dawley

This study was to investigate the mechanism of safflower yellow injection for regulating inflammatory response against myocardial ischemia-reperfusion injury( MIRI) in rats. Male Wistar rats were randomly divided into sham operation group,model group,Hebeishuang group,safflower yellow injection high,medium and low dose groups. MIRI model was established by ligating left anterior descending coronary artery. Myocardial histopathological changes were observed by HE staining; myocardial infarct size was detected by TTC staining; content and changes of tumor necrosis factor-α( TNF-α) and interleukin-6( IL-6),serum creatine kinase( CK),aspartate aminotransferase( AST),and lactate dehydrogenase( LDH) were detected by biochemical method or enzyme-linked immunosorbent assay( ELISA). Western blot assay was used to detect the protein expression of Toll-like receptor 4( TLR4) and nuclear factor-κB( NF-κB p65) in myocardial tissues. The results showed that as compared with the sham operation group,the myocardial arrangement of the model group was disordered,with severe edemain the interstitial,significantly increased area of myocardial infarction,increased activities of AST,CK and LDH in serum,and significantly increased contents of TNF-α and IL-6; the expression levels of TLR4 and NF-κB( p65) protein in myocardial tissues were also increased. As compared with the model group,the myocardial tissues were arranged neatlyin the Hebeishuang group and safflower yellow injection high,medium and low dose groups; the edema was significantly reduced; the myocardial infarct size was significantly reduced; the serum AST,CK,LDH activity and TNF-α,IL-6 levels were significantly decreased,and the expression levels of TLR4 and NF-κB( p65) protein in myocardial tissues were decreased. As compared with the Hebeishuang group,the myocardial infarct size was larger in the safflower yellow injection high,medium and low dose groups; the activities of AST,CK and LDH in serum and the contents of TNF-α and IL-6 in serum were higher,but there was no statistically significant difference in the expression levels of TLR4 and NF-κB( p65) protein in tissues. It is suggested that safflower yellow injection has a significant anti-MIRI effect,and its mechanism may be related to the regulation of TLR-NF-κB pathway to inhibit inflammatory response.
Animals ; Anti-Inflammatory Agents ; pharmacology ; Aspartate Aminotransferases ; blood ; Chalcone ; analogs & derivatives ; pharmacology ; Creatine Kinase ; blood ; Interleukin-6 ; metabolism ; L-Lactate Dehydrogenase ; blood ; Male ; Myocardial Reperfusion Injury ; drug therapy ; Rats ; Rats, Wistar ; Toll-Like Receptor 4 ; metabolism ; Transcription Factor RelA ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

To investigate the spectrum-activity relationship of Trichosanthis Fructus and Trichosanthis Fructus strip pieces for rat myocardial ischemia-reperfusion injury. HPLC fingerprints of Trichosanthis Fructus and Trichosanthis Fructus strip pieces were established, and the values of creatinekinase-MB (CK-MB), myoglobin (MYO) and cardiac troponin-T (cTNT) in 3 dose groups (2.25, 13.5, 27.0 g·kg⁻¹, equivalent to the crude herb g·kg⁻¹) of Trichosanthis Fructus and Trichosanthis Fructus strip pieces with myocardial ischemia-reperfusion injury in rats were measured, and the grey relational analysis was used to study the spectrum-activity relationship of Trichosanthis Fructus and Trichosanthis Fructus strip pieces for rat myocardial ischemia-reperfusion injury. With the dosage increase from 2.25 g·kg⁻¹ to 27.0 g·kg⁻¹, the correlation degree of spectrum-activity relationship of Trichosanthis Fructus and Trichosanthis Fructus strip pieces was also enhanced, but the change trend was different between these two groups. According to the frequency of the top 10 peaks in the correlation degree, peak 17, 14, 16, 19, 32, 12, 26, 30, 4, 6 and 2 were the basic effective substances group of Trichosanthis Fructus, peak 6,14,12,32,30,4 and 6 were the basic effective substances group of Trichosanthis Fructus strip pieces. Peak 6, 14, 12, 32, 30, 4 and 26 in fingerprints of Trichosanthis Fructus and Trichosanthis Fructus strip pieces were the main common pharmacodynamic substance base, among them, peak 6 was 5-hydroxymethyl furfural, peak 14 was vanillic acid and the peak 28 was rutin, but the correlation degree with the efficacy was different. The effect of Trichosanthis Fructus and Trichosanthis Fructus strip pieces on rat myocardial ischemia-reperfusion injury was due to the synergistic effect of the effective substance groups related to the dosage. The essential pharmacodynamic substance groups of Trichosanthis Fructus and Trichosanthis Fructus strip pieces were different, but they shared a common active ingredient group.
Animals ; Chromatography, High Pressure Liquid ; Creatine Kinase, MB Form ; blood ; Cucurbitaceae ; chemistry ; Drugs, Chinese Herbal ; pharmacology ; Fruit ; chemistry ; Myocardial Reperfusion Injury ; drug therapy ; Myoglobin ; blood ; Rats ; Troponin T ; blood