Isoproterenol-induced Myocardial Infarction In Rats Research Articles

Cardioprotective Effects of Aconite in Isoproterenol-Induced Myocardial Infarction in Rats.

Myocardial infarction (MI) is a severe clinical condition caused by decreased or complete cessation of blood flow to a portion of the myocardium. Aconite, the lateral roots of Aconitum carmichaelii Debx., is a well-known Chinese medicine for treatment of heart failure and related cardiac diseases. The present study is aimed at investigating the cardioprotective effect of aconite on isoproterenol- (ISO)- induced MI. The qualitative analysis of aqueous extracts from brained aconite (AEBA) was conducted by HPLC. A rat model of MI induced by ISO was established to examine the effects of AEBA. The cardiac function was assessed by echocardiography. The serum levels of SOD, CK-MB, cTnT, and cTnI were detected to estimate myocardial injury. The pathological changes of heart tissue were evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin-eosin (HE) staining, and Masson's trichrome staining. The expressions of abnormal vascular remodeling and hypoxia-related components and the levels of inflammation-associated genes and proteins were detected by RT-qPCR, western blotting, and immunofluorescence. The contents of benzoylaconine, benzoylmesaconine, benzoylhypacoitine, and hypaconitine in AEBA were 1.35 μg/g, 37.35 μg/g, 57.10 μg/g, and 2.46 μg/g, respectively. AEBA obviously improved heart function through promoting echocardiographic parameters, radial strain, and circumferential strain. The data of TTC staining, HE staining, and Masson's trichrome staining disclosed that AEBA could significantly reduce infarct size, inhibit inflammatory cell infiltration, and decrease the myocardial fibrosis. Moreover, AEBA distinctly suppressed the serum levels of SOD, MDA, CK-MB, cTnT, and cTnI in ISO-induced rats. The results of RT-qPCR indicated that AEBA inhibited the expressions of hypoxia- and inflammation-related genes, including VEGF, PKM2, GLUT-1, LDHA, TNF-α, IL-1β, IL-6, and COX2. In addition, the western blotting and immunofluorescence analyses further confirmed the results of RT-qPCR. In summary, our results indicate that the AEBA could improve ISO-induced myocardial infarction by promoting cardiac function, alleviating myocardial hypoxia, and inhibiting inflammatory response and fibrosis in heart tissue.

Cardioprotective Role of Scopoletin on Isoproterenol-Induced Myocardial Infarction in Rats.

Scopoletin is a phenolic coumarin isolated from a variety of plants and was originally used to treat various diseases including arthritis as well as bone-related diseases. The goal of this study was to determine scopoletin's therapeutic potential in an animal model of myocardial infarction induced with ISO. There were five groups of albino male rats. Group I (control) animals were orally treated with olive oil. Group II (scopoletin) animals were pre-treated orally with a 50-mg dosage of scopoletin for 28 days. Group III (ISO-treated) animals were treated with 85mg/kg of ISO subcutaneously for 2 consecutive days (29th and 30th day). Group IV (scopoletin and ISO) animals were pre-treated orally with 25mg of scopoletin for 28 days before exposure to ISO. Group V (scopoletin and ISO) animals were pre-treated with 50mg of scopoletin for 28 days before exposure to ISO. In the ISO-administered animals, a wider heart-to-body weight ratio, a higher heart weight, higher cardiac diagnostic markers, higher MDA levels and related antioxidant levels, inflammatory, and apoptotic markers were observed. Scopoletin pre-treatment with ISO (25 and 50mg/kg b.wt) significantly reduced heart-to-body weight ratio, cardiac diagnostic markers, MDA, inflammatory markers, and apoptotic markers. Meantime, a pre-treatment with scopoletin increased the levels of antioxidant enzymes. Inflammation and necrosis were observed in the histopathology of heart tissue of ISO-treated animals and these histopathological conditions were reversed by scopoletin pretreatment. The antioxidant and anti-inflammatory properties of ISO-treated rats were shown to be increased by scopoletin, showing its therapeutic potential against cardiovascular diseases. Through the use of its antioxidant and anti-inflammatory properties, scopoletin exhibited anti-myocardial infarction properties. However, further preclinical studies will be required to demonstrate the mechanism of action of scopoletin involved in anti-myocardial infarction.

Effects of exercise preconditioning on NLRP3 and mitochondrial fission in isoproterenol-induced myocardial infarcted rats

Effects of exercise preconditioning on NLRP3 and mitochondrial fission in isoproterenol-induced myocardial infarcted rats

Protective Effects of L-2-Oxothiazolidine-4-Carboxylate during Isoproterenol-Induced Myocardial Infarction in Rats: In Vivo Study.

This study aimed to evaluate the cardioprotective effects of L-2-oxothiazolidine-4-carboxylate (OTC) against isoproterenol (ISO)-induced acute myocardial infarction (MI) in rats. Results demonstrated that OTC treatments inhibited ISO-induced oxidative damage, suppressed lipid peroxidation, and increased superoxide dismutase and catalase activity in the hearts of the treated rats compared to those of the untreated controls. The ISO-related NF-κB activation was reduced due to the OTC treatment, and lower degrees of inflammatory cell infiltration and necrosis in the hearts were observed. In summary, OTC treatments exerted cardioprotective effects against MI in vivo, mainly due to enhancing cardiac antioxidant activity.

Protective effects of silver nanoparticles in isoproterenol-induced myocardial infarction in rats.

BackgroundSilver nanoparticles (AgNPs) are widely used in the medical field, including cardiovascular. However, limited research has investigated the effect of AgNPs on the protection of myocardial infarction (MI).ObjectivesIsoproterenol (Iso)-induced MI and the cardiac protection offered by AgNPs were investigated in the present study. Additionally, we characterized the profile of Ag in the form of nanoparticles.MethodsTwenty-four male Wistar rats were randomly divided into four groups as follows: normal, Iso, Iso + AgNO3, and Iso + AgNP groups. AgNPs and silver ion (AgNO3) were administered intraperitoneally at 2.5 mg/kg BW for 14 days. Iso induction was performed using two doses of 85 mg/kg BW given subcutaneously on days 13 and 14. Blood and cardiac tissue samples were taken 24 h after the last dose of Iso and checked for Creatine Kinase-MB (CK-MB), lactate dehydrogenase in plasma along with oxidative stress parameters, mitochondria biogenesis markers, and inflammation representative genes in cardiac tissue. Additionally, we analyzed the histopathological features in cardiac tissue.ResultsThe silver was confirmed in the form of nanoparticles by its size at intervals of 8.72–37.84 nm. Both AgNO3 and AgNPs showed similar cardioprotective effects, as shown by the decrease in biochemical markers of cardiac toxicity, namely, CK-MB. Additionally, AgNPs group have better efficacy compared with AgNO3 group in ameliorating Iso-mediated oxidative stress production, as evidenced by the significant decrease in malondialdehyde level and increased superoxide dismutase activity (P < 0.0001 and P < 0.01, respectively) in cardiac tissue compared with the Iso group. Mechanistically, AgNPs, but not AgNO3, enhanced the expression levels of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-gamma coactivator 1-alpha in post-MI heart and reduced the protein expression of nuclear factor-kappa B (NF-κB) assessed by western blot analysis. Furthermore, these results were confirmed with the histopathological evaluation of cardiac tissue. Nevertheless, pretreatment with either AgNO3 or AgNPs improved the aspartate aminotransferase level.ConclusionThese results suggested that AgNPs have more superior cardioprotective effect compared with AgNO3 against Iso-induced MI, at least in part through amelioration of NF-κB expression level induced by oxidative stress overproduction.

β-caryophyllene modulates B-cell lymphoma gene-2 family genes and inhibits the intrinsic pathway of apoptosis in isoproterenol-induced myocardial infarcted rats; A molecular mechanism

Myocardial infarction (MI) is one of the top causes of morbidity and mortality in the world. Prevention/treatment of MI is of utmost importance. This study planned to appraise the molecular mechanisms of β-caryophyllene on the intrinsic pathway of cardiomyocyte apoptosis in isoproterenol-induced myocardial infarcted rats. Rats were induced MI by isoproterenol (100 mg/kg body weight). The serum cardiac diagnostic markers, heart lipid hydroperoxides, heart lysosomal thiobarbituric acid reactive substances, and serum/heart lysosomal enzymes were considerably (P < 0.05) augmented, while heart antioxidants, heart lysosomal β-glucuronidase and cathepsin-D were considerably (P < 0.05) lessened in isoproterenol-induced myocardial infarcted rats. A reverse transcription-polymerase chain reaction study revealed altered expressions of B-cell lymphoma gene-2, B-cell lymphoma – extra-large, B-cell lymphoma-2 associated-x, and B-cell lymphoma-2 associated death promoter genes. Further, transmission electron microscopic study depicted damaged heart lysosomal structure. Histological study revealed mononuclear cell infiltration and congested dilated blood capillaries in between affected cardiac muscle fibres. Further, 2,3,5-triphenyl tetrazolium chloride staining showed a larger myocardial infarct size. The β-caryophyllene (20 mg/kg body weight) pre-and co-treatment orally, daily, for 21 days considerably (P < 0.05) ameliorated all these altered biochemical, transmission electron microscopic, molecular and histological parameters evaluated in myocardial infarcted rats. Thus, β-caryophyllene inhibited oxidative stress and lysosomal leakage, preserved the heart, and heart lysosomal structure, and prevented the intrinsic pathway of apoptosis. Moreover, it reduced infarct size. The antioxidant effects of β-caryophyllene are the possible mechanism for the observed anti-oxidative stress, anti-lysosomal damage, anti-apoptotic, and myocardial infarct size limiting effects.

Thymoquinone regulates nitric oxide synthase enzymes and receptor-interacting serine-threonine kinases in isoproterenol-induced myocardial infarcted rats

This study aims to investigate the protective effects of thymoquinone (THQ) in isoproterenol (ISO)-induced myocardial infarction (MI) in rats.Thirty-two rats were divided into four equal groups. Control, THQ; Intragastric(ig) by dissolved 20 mg/kg in 500 μl olive oil at 24-h intervals for 7 days, ISO; On the 6th and 7th days of the experiment, it was dissolved in 1 ml distilled water, 100 mg/kg, subcutaneously(sb), THQ + ISO; THQ was given 20 mg/kg at 24-h intervals for 7 days, 100 mg/kg was given on days 6 and 7 of the ISO experiment. At the end of the experiment, blood and heart tissues were taken and histological, Western blot and biochemical analyzes were performed.In the ISO group, cardiomyocyte damage and large necrotic areas were observed. While neuronal nitric oxide synthase (nNOS) decreased, inducible NOS (iNOS) and endothelial NOS (eNOS) expression increased. Receptor-interacting serine-threonine kinase (RIP/RIPK) RIP1 and RIP3 protein levels were increased. Lactate dehydrogenase (LDH), creatin-kinase (CK-MB) and cardiac troponin I (cTn-I) levels were increased. Atrial natriuretic peptide (ANP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) levels were decreased. THQ caused the reduction of necrotic areas caused by ISO. NOS regulated enzyme levels. Increased ISO-induced decreased RIP1 and RIP3 expressions. THQ regulated the biochemical parameter levels.ISO triggers MI-induced necrosis through NOS enzymes by causing severe histological changes in heart tissue. THQ, on the other hand, reveals that it can be an important antinecrotic agent in the prevention of MI-induced damage by regulating both NOS enzyme levels and necrosis markers.

Combined Antioxidant Formulation of Ascorbic Acid with Resveratrol Ameliorates Isoproterenol-Induced Myocardial Infarction in Rats

The current investigation was proposed to assess the effectiveness of the combination of resveratrol and ascorbic acid against Isoproterenol (ISO)-induced myocardial infarction in rats. The experimental model was divided into six groups (n = 6 in each group). Group I: control, Group 2: isoproterenol (ISO)-100 mg/kg b.wt, Group 3: ISO+Resveratrol (RES) (20 mg/kg b.wt) treated, Group 4: ISO+ Ascorbic acid (AA) (80 mg/kg b.wt) treated, Group 5: ISO+RES (20 mg/kg b.wt)+AA (80 mg/kg b.wt) treated and Group 6 : RES (20 mg/kg b.wt)+ AA (80 mg/kg b.wt) alone treated. The study showed an increase in lipid peroxides and cardiac markers in the serum samples of experimental animals administered with ISO. Treatment with RES and AA individually and a combinational formulation brought a significant decrease in lipid peroxides and cardiac markers. They increased the level of enzymatic antioxidants and non-enzymatic antioxidant levels. Histopathological results showed the distortion of heart architecture among the experimental groups administered with ISO and significant recovery when treated with RES and AA individually and in their combination. The study presents the effective combination of RES and AA in combating ISO-induced myocardial infarction and protection against ROS-mediated oxidative stress.

Bergenin from Bergenia Species Produces a Protective Response against Myocardial Infarction in Rats

Bergenin is a phenolic glycoside that has been reported to occur naturally in several plant species, reported as a cardioprotective. However, bergenin, one of the important phytochemicals in these plants, is still not reported as a cardioprotective. The present study was designed to investigate the cardioprotective effects of bergenin on isoproterenol-induced myocardial infarction in rats. Bergenin and atenolol were administered through intraperitoneal (i.p.) injection to Sprague Dawley (SD) rats in separate experiments for five (5) days. At the end of this period, rats were administered isoproterenol (80 mg/kg s.c.) to induce myocardial injury. After induction, rats were anaesthetized to record lead II ECG, then sacrificed, blood was collected to analyze cardiac marker enzymes, and a histopathological study of the heart tissues was also performed. Pretreatment with bergenin showed a significant decrease in ST-segment elevation, deep Q-wave, infarct size, and also normalized cardiac marker enzymes (cTnI, CPK, CK-MB, LDH, ALT, and AST), particularly at 3 mg/kg, as compared to isoproterenol treated group. Our findings revealed, for the first time, the use of glycoside bergenin as a potential cardioprotective agent against the isoproterenol-induced MI in rats.

Effect of Fraxetin on Oxidative Damage Caused by Isoproterenol-Induced Myocardial Infarction in Rats.

At present, cardiovascular disorders are the most prominent factors for the high morbidity rate globally. The occurrence of myocardial infarction followed by myocardial ischemia is the important cause of high death rates. Various medical treatments are available, yet the mortality and morbidity rate is high. In the present investigation, the cardioprotective property of fraxetin (Fx) is evaluated in myocardial infarction-induced experimental rats. Fraxetin, a phytochemical known as coumarin isolated from Fraxinus rhynchophylla. Fraxetin has numerous pharmacological activities including antioxidant, apoptosis inhibitor, anti-inflammatory, and antimicrobial agent. The experimental mice were split into 4 groups each comprising six animals. Group I was considered the control group; 0.1% NaCl solution was given as dosage. Group II received only Fx; group III was treated with ISO. Group IV was treated with Fx followed by ISO to induce myocardial infarction. In ISO administrated rats, there were changes in the heart weight, activities of cardiac markers, transmembrane protein activity, antioxidant enzymes, pro-inflammatory proteins, lipid profile, and myocardial structures. Pre-treatment of fraxetin in group IV experimental rats resulted in decreased cardiac weight, diminished level of cardiac markers (cardiac troponin T (cTnT), creatine kinase, creatine kinase-MB, and cardiac troponin I (cTnI)), reduced level of oxidative stress biomarkers (LOOH and TBARS) in the plasma and cardiac tissue, amplified level of enzymes in antioxidant defense system (catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GPx)) in the plasma and heart tissue, and elevated level of ATPase activities. The histopathological studies also revealed the potent activity of fraxetin in protecting the cardiac tissues from inflammation and damage. ISO-administrated experimental rats treated with fraxetin exhibit increased antioxidants activity and decreased free radicals. Our study revealed that the administration of fraxetin significantly reduced the extent of myocardial damage during myocardial infarction in rats caused by isoproterenol. Thus, the results prove the cardioprotective effect of fraxetin in MI-induced rats.

Potential cardioprotective effect of octreotide via NOXs mitigation, mitochondrial biogenesis and MAPK/Erk1/2/STAT3/NF-kβ pathway attenuation in isoproterenol-induced myocardial infarction in rats

Myocardial infarction (MI) is a global health care problem, which instigates irreversible cardiac tissue damage and sudden death, necessitating new prevention and management strategies. Hence, the cardioprotective effect of octreotide in MI was scrutinized by tackling the possible underlying trajectories involved. Isoproterenol (ISO)-induced acute MI model was adopted using ISO (85 mg/kg/day, S.C.) for 2 days. Rats in octreotide groups were pretreated with 20 or 40 μg/kg/day S.C. for 8 days and ISO was given on the 7th and 8th days. Octreotide showed a restoration of ECG changes, cardiac hemodynamics abnormalities, serum cardiac markers elevation (creatine kinase MB, troponin I, lactate dehydrogenase, and aspartate aminotransferase), and cardiac histoarchitecture abnormalities. In addition, octreotide pretreatment showed a significant increase in the cardiac and serum level of the diagnostic microRNA-133a. Octreotide attenuates oxidative stress indices (MDA, GSH, SOD, TAC, and HIF-1α), besides a better adjustment of NOX-1/-2/-4 expression and protein levels. Mitochondrial morphology and mtDNA copy number were preserved following the pre-treatment of Octreotide. The inflammatory pathway p38 MAPK/Erk-1/-2/p-STAT3/NF-κB pathway and the proinflammatory cytokines (TNF- α, IL-6, and IL- 1β) were attenuated. The proapoptotic markers (cyt c, caspase-3/-9, and Bax) were also attenuated and the antiapoptotic Bcl2 marker was increased by the preadministration of octreotide. In almost all parameters, Octreotide 40 μg/kg/day was more prominent than its lower dose. Octreotide possesses dose-dependent cardioprotective properties via its antioxidant, anti-inflammatory, and anti-apoptotic capabilities.

Valencene post-treatment exhibits cardioprotection via inhibiting cardiac hypertrophy, oxidative stress, nuclear factor- κB inflammatory pathway, and myocardial infarct size in isoproterenol-induced myocardial infarcted rats; A molecular study

The growing burden of myocardial infarction (MI) becomes a major global health issue that is accountable for considerable mortality worldwide. Hence, it is obligatory to develop a new treatment for MI having lesser side effects. Cardiac hypertrophy, oxidative stress, and inflammatory pathways play crucial roles in the pathogenesis of MI. This investigation established the anti-cardiac hypertrophic, antioxidant, anti-inflammatory, and myocardial infarct size limiting effects of valencene. Rats were induced MI by isoproterenol (100 mg/kg body weight) and then treated with valencene and cardiac sensitive markers, cardiac hypertrophy, oxidative stress, markers of inflammation, nuclear factor- κB inflammatory pathway, and myocardial infarct size was estimated/determined. The serum cardiac diagnostic markers, cardiac hypertrophy, conjugated dienes, markers of inflammation, pro-inflammatory cytokines, and myocardial infarct size were significantly (P < 0.05) increased by isoproterenol. Further, antioxidant enzymes and anti-inflammatory cytokine gene were significantly (P < 0.05) decreased in the heart. The 2, 3, 5-triphenyl tetrazolium chloride dye staining revealed a larger infarct size. Moreover, histological results of myocardial infarcted rat's cardiac tissue revealed separation of cardiac muscle fibers, necrosis, and inflammatory cells. Post-treatment with valencene (12 mg/kg body weight) orally, daily, for two weeks to isoproterenol-induced myocardial infarcted rats reversed all above said structural, biochemical, molecular, and histological parameters investigated, by its anti-cardiac hypertrophic, antioxidant, anti-inflammatory, and myocardial infarct size limiting effects. Thus, valencene is a potential candidate for inhibiting cardiac hypertrophy, oxidative stress, nuclear factor- κB inflammatory pathway, and myocardial infarct size and exhibited cardioprotection in MI.

VALENCENE, A SESQUITERPENE EXHIBITS ANTILIPID PEROXIDATION AND ANTIOXIDANT EFFECTS IN THE PLASMA OF ISOPROTERENOLINDUCED MYOCARDIAL INFARCTED RATS

Aim: The present study was aimed to evaluate the effects of valencene, a sesquiterpene on plasma lipid peroxidation and antioxidants in isoproterenol-induced myocardial infarcted rats. Methods: Rats were induced myocardial infarction by isoproterenol (100 mg/kg body weight) on the 1st and 2nd day and then on the 4th-day valencene treatment was given to rats orally, daily, for 14 days. Results: Isoproterenol-induced myocardial rats showed an increase in the levels of serum myoglobin, plasma thiobarbituric acid reactive substances, and lipid hydroperoxides and a significant decrease in the levels of plasma non-enzymatic antioxidants such as reduced glutathione, vitamin- C, and vitamin-E. Oral treatment with valencene (12 mg/kg/body weight) daily for 14 days significantly reduced serum myoglobin and plasma lipid peroxidation and significantly increased non-enzymatic antioxidants. Conclusion: Thus this study reveals the anti-lipid peroxidation and antioxidant effects of valencene in isoproterenol-induced myocardial infarcted rats.

Preventive effects of (−) epicatechin on tachycardia, cardiac hypertrophy, and nuclear factor- κB inflammatory signaling pathway in isoproterenol-induced myocardial infarcted rats

Myocardial infarction (MI) is a life-threatening condition. No studies were conducted earlier on the effects of (−) epicatechin (EC) on tachycardia, cardiac hypertrophy, and inflammation in MI. Hence, the preventive effects of EC on tachycardia, cardiac hypertrophy, and nuclear factor- κB inflammatory signaling pathway in experimental MI were appraised. This investigation included 4 groups of 24 male albino Wistar rats. Group:1. Normal control, Group: 2. EC (20 mg/kg body weight), Group: 3. Isoproterenol (100 mg/kg body weight), Group:4. EC (20 mg/kg body weight) + Isoproterenol (100 mg/kg body weight). MI was created in rats by isoproterenol (100 mg/kg body weight). The heart rate, heart weight, plasma myoglobin, serum cardiac troponin I, heart conjugated dienes, serum high-sensitivity C-reactive protein, and plasma total homocysteine were considerably (P < 0.05) raised in isoproterenol-induced myocardial infarcted rats. Further, reverse transcription-polymerase chain reaction study revealed a considerable (P < 0.05) increase in the expressions of heart pro-inflammatory cytokines such as nuclear factor- κB, tumor necrosis factor-α, interleukin-1β, interleukin-6, and a considerable (P < 0.05) decrease in anti-inflammatory cytokine gene, interleukin-10 in myocardial infarcted rats. Non-enzymatic antioxidants such as vitamin C, and vitamin E were considerably (P < 0.05) lessened in the heart. EC (20 mg/kg body weight) pre-treatment orally, daily, for 3 weeks prevented all changes in the above-mentioned functional, structural, biochemical, and molecular parameters investigated and improved cardiac function. The possible mechanisms are EC’s anti-tachycardial, anti-cardiac hypertrophic, antioxidant, and anti-inflammatory effects.

Post-Treatment with Valencene Exhibits Cardioprotection via Modulating Cardiac&amp;nbsp; &amp;nbsp;Hypertrophy, and Nuclear Factor-κB Inflammatory Pathway in Isoproterenol-Induced Myocardial Infarcted Rats

Post-Treatment with Valencene Exhibits Cardioprotection via Modulating Cardiac&amp;nbsp; &amp;nbsp;Hypertrophy, and Nuclear Factor-κB Inflammatory Pathway in Isoproterenol-Induced Myocardial Infarcted Rats

Ethyl pyruvate attenuates isoproterenol-induced myocardial infarction in rats: Insight to TNF-α-mediated apoptotic and necroptotic signaling interplay

The current study investigated the prophylactic effect of ethyl pyruvate (EP) in Isoproterenol (ISO) - induced myocardial infarction (MI). Ethyl pyruvate (EP) was given at a dose of 100 mg/kg i.p for 7 days, while isoproterenol (ISO) was administered at a dose of 10 mg/kg s.c. on the 6th and 7th days to induce MI. All parameters were assessed 24 and 48 h following treatment. Interestingly, EP pre-treatment significantly improved ISO-induced hemodynamic alterations and remarkably ameliorated serum levels of cardiac injury markers, Cardiac Troponin I (cTnI) and Cardiac Creatine Kinase (CK-MB). Also, EP notably suppressed levels of oxidative stress markers, total antioxidants (TAO) and malondialdehyde (MDA) as compared to ISO-treated group. Cardioprotective effects of EP were confirmed by histopathological examination. Moreover, EP remarkably attenuated ISO-induced elevation in Tumor Necrosis Factor Alpha (TNF-α) and Nuclear factor kappa-B p65 (NF-κB) expression, along with Interleukin-6 (IL-6), Monocyte chemoattractant protein 1 (MCP-1) and Inducible nitric oxide synthase (i-NOS) levels. Also, EP significantly diminished expression of apoptotic markers; caspase 8, cleaved caspase 3 and apoptotic regulator; cellular FLICE-like inhibitory protein (cFLIP). Finally, EP notably mitigated necroptotic mediators, phosphorylated receptor-interacting serine/threonine protein kinase 1 and 3 (p-RIPK1 and p-RIPK3), phosphorylated mixed lineage kinase domain-like protein (p-MLKL) and heat shock protein 70 (HSP 70) expression as compared to the ISO-treated group. Our study was the first to investigate the effect of EP on the necroptotic signaling. Taken together, EP conferred its cardioprotective effect against ISO-induced MI partially through mitigation of TNF-α and its downstream inflammatory, apoptotic and necroptotic signaling pathways.

Cardioprotective effect of hydroalcoholic extract of Brazilian red propolis against isoproterenol-induced myocardial infarction in rats

BackgroundThe pharmacological effects of propolis have mainly been investigated in various fields of medicine as an essential resource for the prevention and treatment of diseases. PurposeThis study examined the cardioprotective effect of hydroalcoholic extract of Brazilian red propolis (BRPHE) against isoproterenol (ISO)-induced myocardial infarction in rats. MethodsRats were pretreated with BRPHE (50, 75, and 150 mg/kg) for 30 days, with concurrent administration of ISO (85 mg/kg) during the last two days. The hemodynamic, biochemical, histological, and morphometric changes were monitored from control and experimental groups at the end of the experiment, i.e., on the 31st day. Phytochemical compounds were determinated by the UV–Vis spectrophotometric and UPLC-DAD-UV–Vis methods. ResultsISO-induced myocardial infarcted rats showed an increase in cardiac marker enzymes, i.e., in creatine kinase-NAC (CK-NAC) and CK-MB, tachycardia, myocardium necrosis, edema, hemorrhagic areas, infiltration of inflammatory cells like lymphocytes, and increased myocardial infarct size. However, pretreatment of ischemic rats with BRPHE significantly inhibited these effects of ISO. Thus, histopathological findings obtained for the myocardium further confirmed the biochemical findings. Flavonoids and phenols were identified in BRPHE. ConclusionOur results suggested that BRPHE pretreatment ameliorated myocardial injury in ISO-induced myocardial infarcted rats and exhibited cardioprotective activity.

Thymoquinone protects against cardiac mitochondrial DNA loss, oxidative stress, inflammation and apoptosis in isoproterenol-induced myocardial infarction in rats

IntroductionMyocardial infarction (MI) is an ischemic life-threatening disease with exaggerated oxidative stress state that vigorously damages the cardiomyocyte membrane and subcellular structures, including the vital mitochondrial DNA (mtDNA). The mtDNA is responsible for the proper functionality of the mitochondria, which are abundant in cardiomyocytes due to their dynamic nature and energy production requirements. Furthermore, oxidative stress triggers an inflammatory cascade and eventual apoptosis, which exacerbates cardiac injuries and dysfunction. AimThe present study used an isoproterenol (ISP)-induced MI rat model to investigate the role of the main active constituent of Nigella Sativa seeds, thymoquinone (TQ), in preserving the cardiac mtDNA content and ameliorating oxidative stress, inflammation, and apoptosis. MethodsRats in the (TQ + ISP) group were pre-treated with TQ (20 mg/kg/day) for 21 days before the MI induction using ISP (85 mg/kg/day). In addition, negative control and ISP groups were included in the study for comparison. A histopathological examination was performed and serum cardiac parameters (cTnI and LDH) were assessed. In addition, mtDNA content, oxidative stress parameters (MDA, GSH, SOD, GPx, and CAT), inflammatory mediators (IL-6, IL-1β, and TNF-α), and apoptosis markers (BAX, Bcl2, and caspase-3) were detected. ResultsThe results showed that pre- and co-treatment with TQ in the (TQ + ISP) group reversed the histoarchitecture changes, caused a significant decrease in serum cardiac markers, oxidative stress markers, inflammatory cytokines, the apoptosis process, and preserved the cardiac mtDNA content. ConclusionTQ is a cardioprotective agent with an extended effect on preserving the cardiac mtDNA content, in addition to its powerful antioxidant, anti-inflammatory, and anti-apoptotic action.

Andrographolide protects against isoproterenol-induced myocardial infarction in rats through inhibition of L-type Ca2+ and increase of cardiac transient outward K+ currents

Myocardial infarction (MI) is the irreversible injury of the myocardium caused by prolonged myocardial ischemia and is a major cause of heart failure and eventual death among ischemic patients. The present study assessed the protective potentials of andrographolide against isoproterenol-induced myocardial infarction in rats. Animals were randomly divided into four groups: Control (Ctr) group received 0.9% saline solution once daily for 21 days, Isoproterenol (Iso) group received 0.9% saline solution once daily for 19 days followed by 80 mg/kg/day of isoproterenol hydrochloride solution on day 20 and 21, Andrographolide (Andro) group received 20 mg/kg/day of andrographolide for 21 days, and Andrographolide plus Isoproterenol (Andro + Iso) group received 20 mg/kg/day of andrographolide for 21 days with co-administration of 80 mg/kg/day of isoproterenol hydrochloride solution on day 20 and 21. After all treatments, cardiac-specific parameters that define cardiac health and early subacute MI were measured in all groups using both biophysical and pharmacological assay methods. Isoproterenol administration significantly (P < 0.05) increased cardiac mass indexes, systemic cardiac biomarkers, infarct size and caused cardiac histological alterations; significantly (P < 0.05) increased heart rate, QRS & QTc intervals and caused ST-segment elevation; significantly (P < 0.05) increased myocytes shortening, action potential duration (APD), L-type Ca2+ current (ICa,L) density and significantly (P < 0.05) decreased transient outward K+ current (Ito) density typical of the early subacute MI. Interestingly, pretreatment with andrographolide prevented and or minimized these anomalies, notably, by reducing ICa,L density and increasing Ito density significantly. Therefore, andrographolide could be seen as a promising therapeutic agent capable of making the heart resistant to early subacute infarction and it could be used as template for the development of semisynthetic drug(s) for cardiac protection against MI.

Time-dependent influence of infliximab on hemodynamic responses and cardiac injuries of isoproterenol-induced myocardial infarction in rats

Immune-induced inflammation plays an important role both in aggravating and healing of post myocardial infarction (MI) injuries. Potent anti-inflammatory and local immunomodulatory activity of infliximab has been suggested to have modulating effects on immune responses after MI. The aim of the present study was to evaluate the efficacy of infliximab on hemodynamic responses and myocardial injuries following isoproterenol-induced myocardial infarction. Male Wistar rats, weighting 260 ± 20 g were assigned into ten groups (n = 6) of saline (normal saline), infliximab (7 mg/kg), isoproterenol (100 mg/kg for two consecutive days), and isoproterenol plus infliximab (30 min after the second injection of isoproterenol). The heart tissues and serums were analyzed 24, 48, 72, and 96 h post-MI and hemodynamic parameters, histopathological changes, malondialdehyde (MDA), Total antioxidant capacity (TAC), lactate dehydrogenase (LDH), and lactate levels were assessed in the respective groups. Infliximab partially improved hemodynamic depression in the first days after MI, but the heart became more suppressed later. A similar result also obtained at the MDA tissue levels but not serum levels. Anti-inflammatory effects of Infliximab may improve cardiac function and prevent heart tissue injury early after MI; however, it can worsen the condition later by inhibiting compensatory reactions such as cardiac remodeling and tissue repair.