Rat Heart Tissue Research Articles

The Role of Delta-Opioid Receptor in Mediating the Cardioprotective Effects of Morphine Preconditioning via the JAK2/STAT3 Pathway in a Failing Heart

BACKGROUND: Failing heart is more likely to suffer from myocardial ischemia/reperfusion (I/R) injury. This poses a great challenge for anesthesiologists in managing patients with heart failure during major surgery. Evidence from animal studies suggests that the delta-opioid receptor (DOR) contributes to alleviating acute myocardial injuries. However, little is known regarding the cardioprotective effects of cardiac DOR in patients with chronic heart failure. This study aimed to examine DOR expression in failing hearts and explore how DOR regulates the Janus kinase signal transducer and activator of the transcription-3 (JAK/STAT3) pathway to mediate morphine-induced cardio protection in heart failure. METHODS: We measured the DOR protein levels in human and rat heart tissues with chronic heart failure. To investigate the cardioprotective role of DOR, we administered the DOR-specific antagonist, naltrindole (NTD), and JAK2 inhibitor, AG490, before morphine preconditioning (MPC) in an isolated perfusion model of myocardial I/R injury in postinfarcted failing rat heart. We examined the infarct size, cardiac enzymes, cardiac function, cardiomyocyte apoptosis, apoptosis-related proteins, and STAT3 phosphorylation in the heart. RESULTS: The protein levels of DOR were significantly elevated in the myocardial tissues of humans and rats with chronic heart failure, by 1.4-fold (mean difference 0.41; 95% confidence interval [CI], 0.04–0.78; P = .032) and 2.3-fold (mean difference 1.26; 95% CI, 0.25–2.28; P = .009), respectively, compared to control tissues. Disease severity positively correlated with DOR expression (human: R2 = 0.316, P = .004; rat: R2 = 0.871, P = .021). Blocking DOR substantially reversed the cardioprotective effects of MPC in postinfarcted rat hearts, increasing the mean (standard deviation) percentage of infarct size from 15.0 (3.9)% to 30.8 (7.7)% (P < .001). Similarly, AG490 inhibited MPC restoration of cardiomyocyte apoptosis (33.3 [4.2]% vs 16.6 [3.4]%; P < .001). Both NTD and AG490 markedly suppressed STAT3 phosphorylation by 60.1% (mean difference 0.60; 95% CI, 0.27–0.93; P = .002) and 44.1% (mean difference 0.44; 95% CI, 0.06–0.83; P = .027), respectively, and also lowered the Bcl-2/Bax ratio by 85.5% (mean difference 0.86; 95% CI, 0.28–1.43; P = .006) and 68.2% (mean difference 0.68; 95% CI, 0.51–0.85; P < .001) respectively in heart tissues at the end of reperfusion. CONCLUSIONS: DOR protein levels increased in failing hearts of both humans and rats. Blocking cardiac DOR selectively reduced morphine-induced cardio protection by inhibiting the JAK2/STAT3 pathway. These findings indicate that cardiac DOR is a potential therapeutic target for protecting against heart failure due to I/R injury.

Organ toxicities associated with diet-induced obesity in rats: Investigation of changes in activities selected enzymes.

Obesity stands out as one of the most significant health problems in the modern world. The prevalence of high-calorie diets (HCDs) globally exacerbates this condition. Throughout history, plants and plant-derived food products have been utilized for medicinal purposes, demonstrating their efficacy in the treatment and prevention of various diseases. Gundelia tournefortii (GT), a plant of interest, is known to possess beneficial properties. Hence, this study aimed to investigate the immunotoxic and neurotoxic effects of two different doses of GT plant extract on the liver, brain, and heart tissues of obese rats. For this purpose, Wistar male rats were divided into four groups: "CG," "HCDG," "HCDGUN1," and "HCDGUN2" At the conclusion of the study, adenosine deaminase (ADA) and myeloperoxidase (MPO) activities, as well as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) biomarkers, were evaluated in the liver, heart, and brain tissues. The study results revealed a statistically significant increase in ADA and MPO activities in the HCDG group compared to the CG group, alongside a significant decrease in the HCDGUN groups compared to the HCDG group. Regarding AChE and BChE activities, a statistically significant decrease was observed in the HCDG group compared to the CG group, whereas an increase was noted in the HCDGUN groups relative to the HCDG group, with the latter approaching values similar to those of the control group. In conclusion, the intake of GT plant extract exhibited positive effects on the immunotoxic and neurotoxic effects induced by HCD in rats with an experimental obesity model, as evidenced by tissue biomarker evaluations.

Mitochondrial respiratory pathways in immature rat heart tissue using different cardioplegic solutions.

Minor defects in the mitochondrial ATP-generating system and post-cardioplegia oxidative phosphorylation can negatively impact cardiac function in immature hearts. This study aimed to examine the mitochondrial respiratory pathway using three different cardioplegic solutions (Custodiol HTK, St. Thomas, and Del Nido) during moderate (1h) and long (3h) ischemic periods. A total of 41 male Wistar albino rats were utilized in this study. Five experiments were conducted without the use of any cardioplegic solution (CP0 group). To assess both moderate and prolonged ischemic periods, six experiments were carried out in each of the following groups: CP1 group (St. Thomas solution), CP2 group (Custodiol HTK solution), and CP3 group (Del Nido solution). After 1h, the highest mitochondrial respiration rate was observed in the CP3 group and the lowest in the CP1 group (p = 0.006). After adding ADP substrate, the highest mitochondrial ATP-production-coupled respiration was recorded in the CP3 group, which was similar to the control group CP0. After 3h, while evaluating the ratio between mitochondrial respiration ATP-production coupled and basal respiration, significant differences were found between CP1 group and CP3 group (p = 0.035), as well as between the CP1 and CP0 groups (p = 0.045). Additionally, by assessing the condition of the outer mitochondrial membrane using the Cyt C effect (Cyt/Phos [ADP]), significant differences were observed between the CP1 and CP3 group (p = 0.004), as well as between CP1 and CP0 groups (p = 0.003). Del Nido cardioplegic solution provided optimal mitochondrial protection under moderate and long myocardial ischemia conditions.

Development and validation of an LC‒MS/MS method for the determination of cyclocreatine phosphate and its related endogenous biomolecules in rat heart tissues

The cardioprotective drug cyclocreatine phosphate has been awarded Food and Drug Administration-orphan drug designation for the prevention of ischemic injury to enhance cardiac graft recovery and survival in heart transplantation. Cyclocreatine phosphate is the water-soluble derivative of cyclocreatine. Estimating the levels of Cyclocreatine phosphate, Adenosine triphosphate, Creatine Phosphate, Creatine and Cyclocreatine helps us in understanding the energy state as well as evaluating the heart cells’ function. The quantification of endogenous compounds imposes a challenging task for analysts because of the absence of a true blank matrix, whose use is required according to international guidelines. Recently, the International Council for Harmonization issued a new guideline that contains guidance on the validation of methods used to quantify endogenous components, such as the background subtraction approach that was employed in our current study. Specifically, we developed and validated a sensitive, reliable and accurate liquid chromatography-tandem mass spectrometry assay to determine simultaneously the levels of mentioned endogenous compounds in rat heart tissue. Tissue samples were prepared by protein precipitation extraction using water: methanol (1:1). Using Ultra Performance Liquid Chromatography, Chromatographic separation was achieved with ZORBAX Eclipse Plus C18 4.6 × 100 mm,3.5 μm column and conditions as following: ammonium acetate (pH 8.5): acetonitrile, 70:30 mobile phase, 0.7 mL/min flow rate and 25 °C temperature. Electrospray ionization mass detector with Multiple reaction monitoring mode was then employed, using both positive and negative modes, Analysis was carried out using 5.00–2000.00 ng/mL linear concentration range within 2 min for each analyte. According to Food and Drug Administration guidelines for bioanalytical methods, validation was carried out. We investigated the matrix effect, recovery efficiency and process efficiency for the analyte in neat solvent, postextraction matrix and tissue. The results stated mean percentage recoveries higher than 99%, accuracy 93.32–111.99%, and Relative Standard Deviation (RSD) below 15% within the concentration range of our study which indicated that target analytes’ stability in their real matrix is sufficient under the employed experimental conditions.

Transcriptomics changes of calcitonin gene-related peptide in mitigating lipopolysaccharide-induced septic cardiomyopathy

Septic cardiomyopathy (SCM), a complication initiated by sepsis, presents a significant clinical challenge, leading to increased mortality rates. However, the mechanisms of SCM have not been fully uncovered. Our study involved analyzing RNA sequencing (RNA-seq) data from rat heart tissue, along with utilizing molecular docking and molecular dynamics (MD) simulations, to discover key targets and potential pharmacological actions of the calcitonin gene-related peptide (CGRP) against SCM. A lipopolysaccharide-induced SCM model was established in rats (LPS 10 mg/kg, intraperitoneal (i.p.)). Thereafter, the myocardial tissues from the three groups of rats (Ctrl group, LPS group, and CGRP group) (n = 5) were extracted and underwent RNA-seq, followed by bioinformatics analyses. The qPCR-validated hub targets potentially interacting with CGRP were identified. Following this, homology modeling was utilized to obtain the 3D structure of hub targets, and molecular docking was conducted to evaluate the interaction between CGRP and hub targets. MD simulations (300 ns) were performed to confirm the findings further. Our findings demonstrated that CGRP significantly lowered mortality in SCM rats. 633 DEGs were affected by LPS, contrasted with the Ctrl group. 96 DEGs were affected by CGRP compared to the LPS group. In total, ten fully annotated CGRP-triggered hub genes were obtained. The molecular docking and MD simulations indicate that the relationship between CGRP and eight hub genes is extremely strong. This research offers a thorough examination of the possible objectives and fundamental molecular processes of CGRP in combating SCM, laying the groundwork for investigating the potential protective mechanisms of CGRP against SCM.

The interplay of oxidative stress, apoptotic signaling, and impaired mitochondrial function in the pyrethroid-induced cardiac injury: Alleviative role of curcumin-loaded chitosan nanoparticle

This study assessed the consequence of exposure to a pyrethroid insecticide, fenpropathrin (FPN), on the heart and the probable underlying mechanisms in rats. Moreover, the probable protective effect of curcumin-loaded chitosan nanoparticles (CMN-CNP) was evaluated. Forty male Sprague Dawley rats were distributed into four groups orally given corn oil, CMN-CNP (50 mg/kg b.wt), FPN (15 mg/kg b.wt), or CMN-CNP+FPN for 60 days. The results revealed that FPN exposure increased serum cardiac damage indicators. In addition, a substantial increase in the reactive oxygen species and malondialdehyde content but reduced enzymatic and non-enzymatic antioxidants and altered architecture was recorded in the cardiac tissue of FPN-exposed rats. Additionally, a significant down-regulation of expression of the mitochondrial complexes I-V, mitochondrial dynamics, and antioxidants-related genes but up-regulation of apoptosis-related genes was detected in the FPN-exposed group. Immunofluorescence analyses revealed higher amounts of the harmful protein 4-hydroxynonenal in the heart tissue of FPN-exposed rats. Nevertheless, the earlier disturbances were significantly rescued in the FPN+CMN-CNP treated group. Conclusively, our findings reported the cardiotoxic activity of FPN and the involvement of several mitochondrial imbalances as a probable underlying mechanism. Also, the study findings proved the efficacy of CMN-CNP in combating FPN cardiotoxic effects.

Interaction of three weeks HIIT and vitamin D supplementation on some oxidant and inflammatory factors in heart tissue of middle-aged rats

Abstract Aging causes changes in the structure and function of the heart, which increases the number of free radicals and provides the basis for the increase of inflammatory cytokines. Therefore, this study aimed to investigate the interaction of three weeks of high-intensity interval training and vitamin D supplementation on NOX, SOD, NF-κB, and Nrf-2 in the heart tissue of middle-aged rats. In this experimental study, 21 middle-aged rats in the age range of 10-12 months were purchased from the Pasteur Institute and randomly divided into high-intensity interval training (HIIT) (n = 8), HIIT+VitD (n = 8), and Sham (n = 6) groups. After two weeks of adaptation, HIIT was performed for three week and vitamin D was gavage with a dose of 500 units/kg. Finally, the variables were measured through real-time PCR, and a one-way analysis of variance was used for statistical analysis. The results of data analysis showed that after three weeks, the expression of NOX () and SOD () genes increased significantly in the HIIT group compared to the HIIT+VitD group. The interaction of three weeks of high-intensity interval training with vitamin D supplementation can improve oxidative indices, but this effect was more significant in the exercise group.

Effect of Moderate Intensity Interval Training on the Expression of Genes Related to Necroptosis of Heart Tissue in Male Heart Attack Model Rats

Introduction: Myocardial ischemia-reperfusion injury is a set of cellular and molecular patho-mechanisms that lead to the death of living cardiomyocytes and compromised cardiac function. The aim of this study was to determine the effect of moderate intensity interval training on the expression of RIPK-1, RIPK-3 and MLKL genes in the heart of male heart attack model rats. Methods: In this experimental study, thirty 16-week-old male Wistar rats weighing 220 to 280 gr were randomly divided into three groups: control (healthy), myocardial infarction (MI), and moderate intensity interval training. Myocardial infarction was performed by direct intervention with occlusion in the left anterior descending artery (LAD) for 30 minutes. Interval training protocol was performed three days a week, for 8 weeks, with moderate intensity of 60 minutes of interval running on a treadmill, each interval including 4 minutes of running with an intensity of 65-70% of VO2max and 2 minutes of active recovery with an intensity of 50-60% of VO2max. qRT-PCR method was used to check the gene expression of research variables. Data were compared using SPSS software version 16, one-way analysis of variance and Tukey's post hoc test at a significance level of p<0.05. Results: The expression of cardiac RIPK-1, RIPK-3 and MLKL genes were higher in the MI group compared to the control group; however, moderate intensity interval training decreased the expression of RIPK-1, RIPK-3 and MLKL genes compared to the MI group (p=0.001 and p=0.006, respectively). Conclusion: The results of the research showed that myocardial infarction is associated with the activation of the necroptosis cell death pathway, likewise, interval training with moderate intensity has an effect on reducing the expression of necroptosis genes (RIPK1, RIPK3, and MLKL). However, due to the lack of evidences and limitations of research, it still needs more investigations.

The effect of high intensity interval training on asprosin and oxidative stress in the heart tissue of diabetic male rats

Abstract The release of adipokines from adipose tissue depots plays a crucial role in regulating metabolic homeostasis and several other physiological processes in cardiovascular diseases caused by diabetes. In this study, we investigated the effect of high-intensity interval training (HIIT) on asprosin and oxidative stress of heart tissue type 2 diabetic male rats. 24 male Sprague-Dawley rats were divided into four groups: control (C), control training (CT), diabetes (D), and diabetes training (DT). Diabetes was induced by a high-fat diet and low-dose streptozotocin injection. The training group performed 8-week HIIT program on the treadmill. Two-way ANOVA was used to analyse data (). The results showed that there was no significant interaction in plasma asprosin () and SOD2 (), but a significant interaction in heart tissue asprosin () and P-ERK 1/2 () was found. Serum and heart tissue asprosin were higher in Group D than in Group C (p < 0.0001), and also decreased in Group CT compared to Group C (, ), and Group DT compared to Group D (, ). P-ERK 1/2, SOD2, GPX, and HDL-c were lower in Group D than Group C (, , , , respectively) and increased in Group CT compared to Group C (, , , , respectively), and Group DT compared to Group D (, , , , respectively). There was no significant difference between groups in MDA, HOMA, LDL-c, and TG between Group C and Group CT, but it is lower in Group DT than Group D (, , , , respectively). Asprosin is increased in type 2 diabetic rats, and HIIT reduces asprosin and oxidative stress in the heart and improves insulin resistance and lipid profile. Decreased asprosin may have a cardioprotective effect by activating downstream pathways, including regulating P-ERK 1/2 expression and increasing the antioxidant enzyme SOD2.

Proteomic profiling of extracellular vesicles in takotsubo syndrome

Abstract Background/Purpose Takotsubo syndrome (TS) is an acute form of heart failure characterized by transient regional wall motion abnormalities triggered by a stressful event. The mechanisms underlying its development and recovery are poorly understood, resulting in a lack of disease-specific treatments and diagnostic markers. Extracellular vesicles (EVs) play a significant role in cellular communication and have been shown to be important in various diseases. Their involvement in cardiac conditions like TS is an emerging area of research. The primary objective of this study is to isolate and characterize EVs, as well as profile their proteomic profile, from the heart tissue of rats induced with TS. Methods Rats underwent TS induction through the infusion of 1 mg/kg isoprenaline over 15 minutes (TS24h), or were given saline (control). High-resolution echocardiography verified apical ballooning at 6 hours. After 24 hours, heart tissues from apical and basal segments were collected and processed. EV isolation involved tissue slicing, enzymatic digestion, and differential centrifugation steps, including a final iodixanol cushion separation for large and small EVs (Figure 1). Tandem mass tags and mass spectrometry were utilized for global proteomics and any differentially expressed proteins (DEPs) were identified. Analytical techniques such as volcano plots, heatmaps, enrichment analysis, and protein clustering/networks were employed. The strongest clusters (lowest False Discovery Rate and highest intensity) were selected, and their Gene Ontology (GO) terms/pathways were identified. Results Pure, cup-shaped, vesicles ranging from 50-800nm were successfully isolated (figure 1). EVs from apex of control and TS24h hearts had lower protein concentrations compared to their corresponding basal segments. Global proteomic analysis revealed a distinct protein profile in EVs from the apical segment of TS hearts at 24 hours. A total of 256 (TS24h-apex vs control-apex) and 561 proteins (TS24h-apex vs TS24h-base) were differentially expressed. No DEPs were observed when comparing the basal segments of TS24h and control hearts. Functional enrichment analysis of the DEPs showed an abundant change of biological processes related to metabolic lipid processes, inflammatory response, complement activation, reorganization of extracellular matrix. A downregulation was seen for biological processes related to mitochondrial ATP synthesis coupled electron transport and muscle contraction. Conclusion This study demonstrates a distinct EV protein profile in the apical segments of TS hearts, with marked changes in proteins related to metabolic lipid processes, inflammation, and mitochondrial activity. This extensive catalogue of novel proteins sets the stage for future research aimed at identifying potential therapeutic targets and diagnostic biomarkers, and enabling proof-of-concept studies in TS.

Investigation of the usefulness of collagen peptide in intramyocardial injection of human iPS cell-derived cardiomyocytes

Abstract Background Injecting human induced pluripotent stem (iPS) cell-derived cardiomyocytes directly into the heart muscle holds promise as a treatment for heart failure. Achieving better engraftment is crucial for maximizing therapeutic effectiveness. Collagen peptide (CP) is a form of hydrolyzed gelatin known for its resistance to solidification. By adjusting its concentration, the viscosity of CP can be easily managed, potentially influencing the retention and engraftment efficiency of transplanted cells. Purpose We investigated the impact of different CP concentrations as a solvent for intramyocardial injection of human iPS cell-derived cardiomyocytes. Methods Initially, we examined the leakage of CP solution from the injection site using chicken meat and ex vivo rat heart. Subsequently, an in vivo experiment was conducted using beating rat myocardium injected with CP solution and Indian ink to assess CP diffusion in dynamic heart tissue. Finally, we performed intramyocardial injections of human iPS cell-derived cardiomyocytes onto a myocardial infarction model in immunosuppressed rats (1.0×107 cells/rat), followed by echocardiographic evaluation of cardiac function four weeks post-transplantation (N=3-6). Results There was less leakage from the injection site at lower CP concentration (10%) compared to higher concentration (20%), particularly in chicken or ex vivo rat heart tissue under static, non-beating conditions (chicken; 10% vs. 20% CP: 3.2±0.7% vs. 11.6±0.8%, P=0.01 / rat heart; 1.5±0.9% vs. 6.8±1.1%, P=0.0072). However, when examining fluid leakage from the cross-section of ex vivo rat hearts, we observed significantly higher leakage, regardless of CP concentration (10% CP: 45.7±2.7%, 20% CP: 59.1±8.1%), suggesting that CP diffusion within myocardial tissues had a greater influence on local retention than leakage from the injection site. Subsequently, in an experiment using beating rat myocardium and Indian ink, we observed significant suppression of diffusion in tissues treated with CP solution, with the 20% concentration showing a tendency to remain at the injection site (0% CP: 24.5±6.2 mm2, 10% CP: 6.9±7.1 mm2, 20% CP: 10.6±3.3 mm2, P=0.005). This indicates that 20% CP, rather than 10% CP, may be more suitable for local retention in tissues experiencing intra-tissue pressure, such as the beating myocardium. Finally, in vivo experiment using a myocardial infarction model of rat, there was no significant difference in left ventricular ejection fraction (LVEF) when cardiomyocytes were transplanted with 10% CP (0％ CP: 56.1±8.9%, 10%CP: 61.9±5.2%, P=0.92). However, there was a trend towards improved LVEF with the 20% CP solution (0% CP: 56.1±8.9%, 20%CP: 68.8±7.9%, P=0.13), Conclusion Twenty-percent CP may be more beneficial for treating myocardial ischemia due to enhanced retention and engraftment of transplanted cardiomyocytes.

Examining the Cardioprotective Effects of Aerobic Exercise Combined with Crocin or Berberine on Methamphetamine-Induced Heart Damage in Female Rats

Background: While the harmful effects of methamphetamine abuse on the heart are well-known, the solutions to deal with these damages are not well-known. Objectives: This study aimed to investigate whether aerobic exercise combined with supplements such as Crocin and Berberine can potentially protect against methamphetamine-induced changes in the heart tissue of female rats. Methods: Forty-two female rats were randomly assigned into seven groups (n = 6). The groups included healthy control, methamphetamine, methamphetamine + exercise, methamphetamine + Crocin, methamphetamine + Berberine, methamphetamine + exercise + Crocin, and methamphetamine + exercise + Berberine group. Methamphetamine (10 mg/kg) was injected intraperitoneally over five days. The animals were administered Crocin via intraperitoneal injection at 40 mg/kg during a four-week withdrawal period. At the same time, Berberine was dissolved in drinking water at 100 mg/kg concentration. The aerobic training consisted of running at 25 m/min for 30 minutes. A light microscope was used to observe the structural changes. Data analysis was performed using non-parametric Kruskal-Wallis and Mann-Whitney U tests by SPSS 26, with a significance level of 5%. Results: The results of the study indicate that methamphetamine use causes hyperemia, inflammation, and histopathological damage in the heart cells and tissue (P = 0.001). The combination of exercise with Crocin significantly eliminated methamphetamine-induced heart tissue damage (P = 0.001) and improved cardio-respiratory endurance compared to control (P = 0.004) and methamphetamine (P = 0.01) groups. The combination of aerobic exercise with Berberine removed methamphetamine-induced heart cell damage (P = 0.001), and improved cardio-respiratory endurance compared to control (P = 0.024) and methamphetamine (P = 0.05) groups. In addition, all intervention groups showed a significant reduction in hyperemia and inflammation compared to the methamphetamine group (P = 0.001). Conclusions: A combination of exercise with either Crocin or Berberine supplements demonstrated potential benefits in mitigating some of the harmful structural effects of methamphetamine and improving cardio-respiratory endurance.

The activated caveolin-3/μ-opioid receptor complex drives morphine-induced rescue therapy in failing hearts.

Opioid analgesics can alleviate ischaemia/reperfusion (I/R) injury in chronic heart failure. However, the underlying mechanisms and targets remain unknown. Here, we investigate if caveolin-3 (Cav3) interacts with μ opioid receptors and if Cav3-μ receptor interactions play a role in morphine-induced cardioprotection in failing hearts. Cav3 and μ receptor proteins in human and rat heart tissue were determined by western blot, immunofluorescence and co-immunoprecipitation. Methyl-β-cyclodextrin (MβCD), a destroyer of caveolae, and AAV-Cav3 shRNA were used to reduce Cav3 expression in failing rat hearts. CTOP, a specific μ antagonist, was administrated before morphine preconditioning in perfused failing heart models of myocardial I/R injury. Levels of Cav3 and μ receptor proteins were significantly higher in human and rat myocardial tissues with heart failure than in control tissues. Cav3 and μ receptor expression levels were positively correlated with disease severity. The signal of the cardiac Cav3 protein was colocalized with μ receptor in both the human and rat heart sections. Disruption of caveolae in the failing heart by either MβCD or AAV-Cav3 shRNA significantly inhibits morphine-induced phosphorylation of ERK1/2 and cardioprotection. Administration of CTOP substantially reduced Cav3 expression and morphine-induced cardioprotective effect in heart failure. Our data suggest that up-regulation of the Cav3/μ receptor complex is critical for morphine protection of the failing heart against I/R injury by regulating the ERK1/2 pathway. The activated Cav3/μ receptor complex is an understudied therapeutic target for opioid treatment of heart failure and ischaemic insult.

Melatonin Mediates Cardiac Tissue Damage under Septic Conditions Induced by Lipopolysaccharide.

Lipopolysaccharide (LPS) is known to induce oxidative stress and inflammation, leading to significant damage in cardiac tissues. This study investigates the protective effects of melatonin (MLT) against LPS-induced oxidative damage, inflammation, and apoptosis in rat heart tissue. Rats were divided into four groups (n = 6 per group): control, melatonin-treated, LPS-treated, and LPS + melatonin-treated. Oxidative stress markers, including thiobarbituric acid-reactive substances (TBARSs) and advanced oxidation protein products (AOPPs), were measured. Additionally, inflammatory markers, such as interleukin-6 (IL-6) levels, inducible nitric oxide synthase (iNOS) and nitric oxide (NO) content, and apoptotic markers, caspase-3, caspase-9, and acidic DNase activity, were evaluated. LPS treatment significantly increased TBARS, AOPP, and IL-6 levels, as well as the activity of caspase-3, acidic DNase and iNOS and NO content compared to the control group. Co-treatment with melatonin significantly reduced the levels of TBARS and AOPP levels, and caspase-3 and acidic DNase activities nearly matched those of the control group, while caspse-9 was still slightly increased. Interestingly, IL-6, iNOS and NO levels were significantly decreased but did not fully match the values in the control group. Melatonin mitigates LPS-induced oxidative stress, inflammation, and apoptosis in rat heart tissue by affecting all studied parameters, demonstrating its potential as a therapeutic agent for conditions characterized by oxidative stress and inflammation. Further research is warranted to explore the clinical applications of melatonin in cardiovascular diseases.

Ling gui shen fu decoction ameliorates cardiac injury in ischemic heart disease rats by regulating ANP32A/HIF2α/HMGB1 signal route

Purpose: To investigate the effect of ling gui shen fu decoction (LGSFD) on cardiac injury and cardiomyocyte apoptosis in rats with ischemic heart disease (IHD), and to elucidate the underlying molecular mechanism. Methods: An IHD rat model was established by performing coronary artery occlusion surgery on the left anterior descending (LAD) of rats. The rats were assigned equally to 5 groups: sham-operated group (sham group), IHD group, IHD + perindopril group, IHD + low- dose LGSFD group (IHD + LGSFD-L group), and IHD + high-dose LGSFD group (IHD+LGSFD-H group). The LGSFD was given via gavage. A hypoxia-induced cardiomyocyte model was established by subjecting H9C2 cells to hypoxia. Then, LGSFD-containing serum or blank serum was used to treat the hypoxic rat cardiomyocytes (H9C2). The severity of cardiac injury and extent of apoptotic changes in cardiomyocytes was determined using hematoxylin-eosin (H&E) staining and TUNEL staining, while immunoblotting was used to measure the protein expressions of ANP32A, p-AKT, AKT, HIF-2α, p-mTOR, mTOR and HMGB1. Results: The cardiac injury of rats in the LGSFD groups was significantly reversed, relative to the IHD group (p < 0.05). Moreover, LGSFD reduced the level of apoptosis in hypoxia- induced H9C2 cells and upregulated the concentrations of ANP32A, p-AKT, HIF-2α and p-mTOR. However, the expression levels of HMGB1 were decreased in the heart tissues of IHD rats and hypoxic H9C2 cells. Silencing of ANP32A with ANP32A siRNA (siANP32A) down- regulated ANP32A, p-AKT, HIF-2α and p-mTOR, but up-regulated apoptosis and expression levels of HMGB1 in hypoxic H9C2 cells. Conclusion: LGSFD ameliorates cardiac injury in IHD rats by inhibiting cardiomyocyte apoptosis via the ANP32A/HIF-2α/HMGB1 axis. Further investigations are recommended into the specific mechanism of LGSFD effect using clinical samples, in order to facilitate its clinical development.

Analysis of Differentially Expressed Murine miRNAs in Acute Myocardial Infarction and Target Genes Related to Heart Rate.

This study aims to investigate the expression profile of miRNAs significantly dysregulated after acute myocardial infarction (AMI) and their potential targets. After the establishment of a mouse model of AMI, RNA was extracted from mouse infarcted myocardium. Paired-end sequencing was then performed using the Illumina NovaSeq 6000 system to explore the expression profile of miRNAs. Target genes of downregulated differentially expressed miRNAs (DEmiRNAs) were predicted with miRanda (version 3.3a) and TargetScan (version 6.0). Cytoscape was used to construct a DEmiRNA-mRNA regulatory network to show the regulatory relationship. RT-qPCR was performed to measure miR-142a-3p expression in H2O2-treated rat cardiomyocyte H9c2 cells and heart tissues of MI rats. Cell counting kit-8 and TUNEL assays were conducted to detect H9c2 cell viability and apoptosis. There were 33 differentially expressed miRNAs, of which 3 were significantly upregulated and the rest 30 were significantly downregulated. Target genes of these miRNAs were identified, and their functional enrichment was analyzed using gene ontology (GO) analysis. Importantly, target genes that can regulate heart rate and their paired upstream miRNAs attracted attention. Significant expression correlation between heart rate-related targets (Epas1, Bves, Hcn4, Cacna1e, Ank2, Slc8a1, Pde4d) and paired miRNAs (miR-142a-5p, miR-7b-5p, miR-144-3p, miR-34c-5p, miR-223-3p, miR-18a-5p) in mouse myocardial tissues was identified. MiR-142a-3p was downregulated in H9c2 cells and rat infarct tissues, and overexpressing miR-142a-3p restrains H2O2-induced H9c2 cell apoptosis. Cardioprotective miRNAs, such as miR-142a-3p, were identified in mouse myocardial tissues, and some specific miRNA-target pairs are associated with heart rate regulation.

The Effect of Increasing Aerobic Exercise on the Expression of NF-κB and COX-2 Genes in Heart Tissue of Rats Under a High-fat Diet

Background: Several studies have shown that obesity alters the function and structure of the heart. Objectives: This study examined the impact of increasing aerobic exercise (IAE) on the mRNA expression of Cyclooxygenase-2 (COX-2) and nuclear factor Kappa B (NF-κB) in the cardiac tissue of rats fed a high-fat diet (HFD). Methods: Twenty-four male Wistar rats were divided into two groups and fed two types of diets for eight weeks: Control and HFD groups. After eight weeks, the rats on the HFD were further divided into HFD and HFD + IAE groups. The exercise program was conducted for six weeks, with five sessions per week, progressing from moderate to high intensity. The program followed the principle of gradual overload and was based on the maximum speed of the rats. The expression of COX-2 and NF-κB genes was assessed. Results: The expression of COX-2 and NF-κB genes increased in the HFD group compared to the control group. After six weeks, the expression of NF-κB and COX-2 genes decreased in the HFD + IAE group compared to the HFD group. Conclusions: Six weeks of IAE appears to reduce the inflammatory process in rats with HFD-induced obesity.

The Effect of Chronic Immunosuppressive Regimen Treatment on Apoptosis in the Heart of Rats.

Chronic immunosuppressive therapy is currently the only effective method to prevent acute rejection of a transplanted organ. Unfortunately, the expected effect of treatment brings a number of grave side effects, one of the most serious being cardiovascular complications. In our study, we wanted to investigate how treatment with commonly used immunosuppressive drugs affects the occurrence of programmed cardiac cell death. For this purpose, five groups of rats were treated with different triple immunosuppressive regimens. Cardiac tissue fragments were subjected to the TUNEL assay to visualize apoptotic cells. The expression of Bcl-2 protein, Bax protein, caspase 3 and caspase 9 was also assessed. This study indicates that all immunosuppressive protocols used chronically at therapeutic doses result in an increased percentage of cells undergoing apoptosis in rat heart tissue. The greatest changes were recorded in the TMG (rats treated with tacrolimus, mycophenolate mofetil and glucocorticosteroids) and CMG (rats treated with cyclosporin A, mycophenolate mofetil and glucocorticosteroids) groups. The TRG (rats treated with rapamycin, tacrolimus and glucocorticosteroids) group showed the lowest percentage of apoptotic cells. The internal apoptosis pathway was confirmed only in the TMG group; in the remaining groups, the results indicate programmed cell death via the receptor pathway.

Protective Effect of Carvacrol against Oxidative Damage in Aged Rats.

Aging affects cellular functions and impairs tissue homeostasis. Carvacrol, a polyphenolic compound, has been shown to exert a wide range of pharmacological effects, such as antioxidant, anti-inflammatory, and anticancer characteristics. This investigation aimed to evaluate the effect of carvacrol in elderly male rats. Carvacrol at a dose of 15 or 30 mg/kg was administrated daily per os for 60 days to aged rats. The liver, heart, and kidney samples were taken for the analysis of oxidative stress markers. Serum samples were used to evaluate liver enzymes (alanine transaminase (ALT) and aspartate aminotransferase (AST)). The levels of malondialdehyde (MDA) in the liver, heart, and kidney tissues of aged rats were higher. Conversely, the level of thiol was lower in the mentioned tissues than in the young control group. The levels of MDA in the liver, heart, and kidney tissues of aged rats were significantly reduced by carvacrol, which was accompanied by increased levels of total thiol. ALT and AST levels were higher in the serum of aged rats than in the young control ones. Carvacrol decreased ALT and AST levels in the serum of aged rats versus aged control rats. Carvacrol can be effective in protecting susceptible aged tissues and organs by increasing antioxidant defenses and decreasing liver enzymes.

The interplay between doxorubicin chemotherapy, antioxidant system, and cardiotoxicity: Unrevealing of the protective potential of tannic acid.

Cardiotoxicity is the leading side effect of anthracycline-based chemotherapy. Therefore, it has gained importance to reveal chemotherapy-supporting strategies and reliable agents with their mechanisms of action. Tannic acid (TA), a naturally occurring plant polyphenol, has diverse physiological effects, including anti-inflammatory, anticarcinogenic, antioxidant, and radical scavenging properties. Therefore, this study was designed to investigate whether TA exerts a protective effect on mechanisms contributing to anthracycline-induced cardiotoxicity in rat heart tissues exposed to doxorubicin (DOX). Rats were randomly divided into control and experimental groups and treated with (18mg/kg) DOX, TA (50mg/kg), and DOX+TA during the 2 weeks. Cardiac gene markers and mitochondrial DNA (mtDNA) content were evaluated in the heart tissues of all animals. In addition to major metabolites, mRNA expression changes and biological activity responses of components of antioxidant metabolism were examined in the heart tissues of all animals. The expression of cardiac gene markers increased by DOX exposure was significantly reduced by TA treatment, whereas mtDNA content, which was decreased by DOX exposure, was significantly increased. TA also improved antioxidant metabolism members' gene expression and enzymatic activity, including glutathione peroxidase, glutathione s-transferase, superoxide dismutase, catalase, and thioredoxin reductase. This study provides a detailed overview of the current understanding of DOX-induced cardiotoxicity and preventive or curative measures involving TA.