Fecal metabolomics based on mass spectrometry to investigate the mechanism of qishen granules against isoproterenol-induced chronic heart failure in rats.

Qishen granules, derived from clinical experience formula, has been widely used to improve and treat myocardial ischemic chronic heart failure in China. However, the mechanism of action of Qishen granules in the treatment of chronic heart failure is unclear. This study aimed to discover potential biomarkers of isoproterenol-induced chronic heart failure rats and investigate the potential mechanism of Qishen granules treatment of chronic heart failure. The fecal metabolomics method based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was used to analyze the therapeutic effect and metabolic changes of Qishen granules on chronic heart failure rats. Totally, 17 potential biomarkers were identified, involving bile acid metabolism, fatty acid metabolism, inflammatory response, and amino acid metabolism. For bile acid metabolism, we selected 12 bile acids (two of which were potential biomarkers in nontargeted metabolomics) for quantitative analysis. The quantitative results of bile acids showed that after Qishen granules treatment, the contents of bile acids such as ursodeoxycholic acid and glycodeoxycholic acid were similar to those of health group. This study helps to understand the pathogenesis of isoproterenol-induced chronic heart failure and the therapeutic mechanism of Qishen granules from the perspective of metabolic pathways.

Role of TRPP2 in mouse airway smooth muscle tension and respiration.

The transient receptor potential polycystin-2 (TRPP2) is encoded by the Pkd2 gene, and mutation of this gene can cause autosomal dominant polycystic kidney disease (ADPKD). Some patients with ADPKD experience extrarenal manifestations, including radiologic and clinical bronchiectasis. We hypothesized that TRPP2 may regulate airway smooth muscle (ASM) tension. Thus, we used smooth muscle-Pkd2 conditional knockout (Pkd2SM-CKO) mice to investigate whether TRPP2 regulated ASM tension and whether TRPP2 deficiency contributed to bronchiectasis associated with ADPKD. Compared with wild-type mice, Pkd2SM-CKO mice breathed more shallowly and faster, and their cross-sectional area ratio of bronchi to accompanying pulmonary arteries was higher, suggesting that TRPP2 may regulate ASM tension and contribute to the occurrence of bronchiectasis in ADPKD. In a bioassay examining isolated tracheal ring tension, no significant difference was found for high-potassium-induced depolarization of the ASM between the two groups, indicating that TRPP2 does not regulate depolarization-induced ASM contraction. By contrast, carbachol-induced contraction of the ASM derived from Pkd2SM-CKO mice was significantly reduced compared with that in wild-type mice. In addition, relaxation of the carbachol-precontracted ASM by isoprenaline, a ß-adrenergic receptor agonist that acts through the cAMP/adenylyl cyclase pathway, was also significantly attenuated in Pkd2SM-CKO mice compared with that in wild-type mice. Thus, TRPP2 deficiency suppressed both contraction and relaxation of the ASM. These results provide a potential target for regulating ASM tension and for developing therapeutic alternatives for some ADPKD complications of the respiratory system or for independent respiratory disease, especially bronchiectasis.

Anti-Ischemic Activity of Fabomotizole Hydrochloride under Conditions of Endothelial Dysfunction.

Anti-ischemic activity of fabomotizole hydrochloride was studied on the model of subendocardial ischemia in rats with endothelial dysfunction. Endothelial dysfunction was modeled by intragastric administration of methionine (3 g/kg, once a day for 7 days). Acute subendocardial ischemia was induced in narcotized rats by intraperitoneal injection of isoproterenol (20 µg/kg/min over 5 min). Fabomotizole hydrochloride (intraperitoneally, 15 mg/kg) significantly reduced isoproterenol-induced ST segment depression in animals with endothelial dysfunction and with intact vasculature.

Preventive effect of apigenin against isoproterenol-induced apoptosis in cardiomyoblasts.

We investigated the effect of apigenin, a dietary flavonoid, on isoproterenol hydrochloride (ISO)-induced apoptotic signaling in cardiomyoblast H9C2 cells. The results showed that apigenin treatment (10 µM) prevented ISO (31.25 µM)-induced lipid peroxidative levels and antioxidants status in H9C2 cells. Furthermore, apigenin inhibited expression of inflammatory markers in ISO-treated cells. In addition, apigenin prevented ISO-induced DNA damage and apoptotic signaling through modulating the expression of Bax, caspase-3, -8 and -9, cytochrome c, and Fas proteins in H9C2 cells. It is concluded that apigenin prevents ISO-induced antioxidants depletion, oxidative DNA damage, inflammatory, and apoptotic signaling in H9C2 cells. Thus, the present results demonstrated that apigenin has a cardioprotective effect on cardiomyoblasts cells.

Triptolide alleviates isoprenaline-induced cardiac remodeling in rats via TGF-ß1/Smad3 and p38 MAPK signaling pathway.

Triptolide (TPL) is a diterpene triepoxide with potent immunosuppressive and anti-inflammatory properties. It is the main effective component of the traditional Chinese herb Tripterygium wilfordii Hook F and has been used in China for centuries to treat immune-related disorders. The present study was conducted to investigate the effects of TPL on cardiac remodeling in rats. Age matched male Wistar rats were used in this study. Cardiac remodeling rat model was established by hypodermic injection of isoprenaline for ten days. The rats were treated with TPL (20 or 100 µg/kg/d) for six consecutive weeks. At the end of the study, the cardiac function, collagen volume fraction, perivascular collagen area and hydroxyproline concentration were studied. Echocardiography, Masson staining, immunohistochemistry, western blot and real-time polymerase chain reaction were performed. The protein and mRNA expression of transforming growth factor-ß1 (TGF-ß1), drosophila mothers against decapentaplegic protein 3 (Smad3) and p38 mitogen activated protein kinase (p38 MAPK) were analyzed. The results indicated that TPL treatment significantly reduced the collagen volume fraction, perivascular collagen area, ventricular weight/body weight ratio and hydroxyproline concentration in myocardial tissue compared with the model group. In addition, it also improved the cardiac function. TPL attenuated cardiac remodeling in rats by down-regulating the p38 MAPK and TGF-ß1/Smad3 signaling pathways. TPL treatment significantly attenuated cardiac fibrosis and improved cardiac function through suppressing the p38 MAPK and TGF-ß1/Smad3 signaling pathway in isoprenaline-induced cardiac remodeling rats. Our findings suggested that TPL might be a novel complementary medicine in the treatment of chronic heart failure.

Cardioprotective role of H3R agonist imetit on isoproterenol-induced hemodynamic changes and oxidative stress in rats.

The cardioprotective role of histamine H3 receptor (H3R) agonist imetit (IMT) in isoproterenol (ISO)-induced alterations of hemodynamic and oxidative stress was investigated in Wistar rats. In this study, rats were treated with IMT (5 and 10 mg/kg, per orally [p.o.]), carvedilol (10 mg/kg, p.o.) and ISO control group (normal saline) for 7 d, with concurrent subcutaneous administration of ISO (85 mg/kg) at 24 h interval on last two consecutive days whereas control group was administered with vehicle only. ISO significantly attenuated cardiac antioxidant enzymes superoxide dismutase, catalase and increased plasma cardiac injury biomarkers creatine kinase-MB, alanine transaminase and aspartate transaminase. ISO also altered cardiac activity as evidenced by decrease in blood pressure (34.60%) and increase in heart rate (11.40%). The damage due to oxidative stress was revealed by histopathology alterations such as myocyte necrosis, myofibrillar degeneration and pyknotic nucleus. However, pre-treatment with IMT demonstrated restoration of hemodynamic alterations along with significant preservation of antioxidants and myocyte injury-specific marker enzymes. Furthermore, protective effect of IMT was reconfirmed by the histopathological salvage of myocardium. Results of the present study demonstrated the cardioprotective potential of IMT, as evidenced by favorable improvement in ISO-induced hemodynamic, plasma cardiac biomarkers and tissue antioxidant status along with maintenance of integrity of myocardium.

An enantiomerically pure formulation of esmolol attenuates hypotension and preserves heart rate control in dogs.

BACKGROUND: Esmolol is marketed as a racemate (RS-esmolol) with hypotension being the most frequently reported adverse event. Previously, it has been shown that the S-enantiomer (S-esmolol) possesses all of the heart rate (HR) control. The authors studied whether S-esmolol alone mitigates hypotension at similar degrees of HR control compared with RS-esmolol. METHODS: The effects of RS- and S-esmolol on blood pressure (BP) were compared at multiple infusion rates producing similar HR control in dogs (N=21). Differences in BP were further interrogated by monitoring global cardiovascular function and included the R-enantiomer (R-esmolol) (N=3). RESULTS: S-esmolol at half the rate (µg kg min) of RS-esmolol provided the same degree of HR control over all infusion rates. RS-esmolol lowered BP by 3, 6, 11, 20, and 38 mmHg at 90, 300, 600, 1,000, and 2,000 µg kg min, compared with 2, 4, 5, 10, and 16 mmHg at 45, 150, 300, 500, and 1,000 µg kg min for S-esmolol. Decreased BP with RS-esmolol was attributed to decreases in left ventricular developed pressure (LVDP) (-34 mmHg), LVdP/dt+max (-702 mmHg/s), and cardiac output (-1 l/min). R-esmolol also decreased BP (-10 mmHg), LVDP (-10 mmHg), LVdP/dt+max (-241 mmHg/s), and cardiac output (to -0.2 l/min). S-esmolol reversed these trends toward pre-esmolol values by increasing BP (+13 mmHg), LVDP (+12 mmHg), LVdP/dt+max (+76 mmHg/s), and cardiac output (+0.4 l/min). CONCLUSIONS: R-enantiomer provided no HR control, but contributed to the hypotension with RS-esmolol, which appears to be due to negative inotropy. Thus, an S-enantiomer formulation of esmolol may provide similar HR control with less hypotension.

Modulation of nerve-evoked contractions by ß3-adrenoceptor agonism in human and rat isolated urinary bladder.

Activation of ß3-adrenoceptors has been shown to have a direct relaxant effect on urinary bladder smooth muscle from both rats and humans, however there are very few studies investigating the effects of ß3-adrenoceptor agonists on nerve-evoked bladder contractions. Therefore in the current study, the role of ß3-adrenoceptors in modulating efferent neurotransmission was evaluated. The effects of ß3-adrenoceptor agonism on neurogenic contractions induced by electrical field stimulation (EFS) were compared with effects on contractions induced by exogenous acetylcholine (Ach) and αß-methylene adenosine triphosphate (αß-meATP) in order to determine the site of action. Isoproterenol inhibited EFS-induced neurogenic contractions of human bladder (pD2=6.79; Emax=65%). The effect of isoproterenol was selectively inhibited by the ß3-adrenoceptor antagonist L-748,337 (pKB=7.34). Contractions induced by exogenous Ach (0.5-1µM) were inhibited 25% by isoproterenol (3µM) while contractions to 10Hz in the same strip were inhibited 67%. The selective ß3-adrenoceptor agonist CL-316,243 inhibited EFS-induced neurogenic contractions of rat bladder (pD2=7.83; Emax=65%). The effects of CL-316,243 were inhibited in a concentration dependent manner by L-748,337 (pA2=6.42). Contractions induced by exogenous Ach and αß-meATP were significantly inhibited by CL-316,243, 29% and 40%, respectively. These results demonstrate that the activation of ß3-adrenoceptors inhibits neurogenic contractions of both rat and human urinary bladder. Contractions induced by exogenously applied parasympathetic neurotransmitters are also inhibited by ß3-agonism however the effect is clearly less than on neurogenic contractions (particularly in human), suggesting that in addition to a direct effect on smooth muscle, activation of prejunctional ß3-adrenoceptors may inhibit neurotransmitter release.

Metformin protects the myocardium against isoproterenol-induced injury in rats through alleviating endoplasmic reticulum stress.

Clinical studies have suggested that metformin, a widely used antidiabetic agent, exerts a direct cardioprotective effect on cardiovascular disease in addition to its blood glucose-lowering activity. This study was designed to identify the role of metformin in rats with isoproterenol (ISO)-induced myocardial injury and to investigate its underlying mechanism. A rat model of myocardial ischemic injury was established by the subcutaneous injection of a high dose of ISO, a beta-adrenergic agonist. The results showed that pretreatment of metformin significantly reduced rat mortality induced by ISO, attenuated the increased plasma lactate dehydrogenase activity and myocardium malondialdehyde level, alleviated the hemodynamic disturbance, inhibited the upregulated gene expression of myocardial probrain natriuretic peptide and alleviated the myocardial morphological injury and apoptosis induced by ISO. Furthermore, western blot analysis showed that metformin suppressed the overexpression of the endoplasmic reticulum stress (ERS) markers cleaved caspase-12 and CEBP-homologous protein induced by ISO and increased the phosphorylation of AMP-activated protein kinase (AMPK). In conclusion, these data suggest that metformin might protect the myocardium against acute ischemic injury in rats at least partially by activating AMPK and alleviating aberrant ERS. These findings might provide further experimental evidence for treating patients at risk of ischemic heart disease with metformin.

Effect of calcitonin gene-related peptide on isoprenaline-induced cardiac fibroblast proliferation and collagen expression.

OBJECTIVE: To explore the inhibitory effect of calcitonin gene-related peptide (CGRP) on cardiac fibroblast proliferation and collagen synthesis induced by isoprenaline and the underlying mechanism. METHODS: The primary cultured cardiac fibroblasts were incubated with isoprenaline (10(-5) mol/L) for 48 h after pretreatment with CGRP (10(-8) or 10(-7) mol/L) for 1 h. Cell activity was detected by MTT. The mRNA expression of collagen (types I and III) and connective tissue growth factor (CTGF) was determined by RT-PCR, and the levels of intracellular ROS were determined by DCFH-DA fluorescent probe. RESULTS: Isoprenaline significantly promoted fibroblast proliferation and up-regulated collagen (types I and III) and CTGF mRNA expression concomitantly with an increase in ROS production, which were attenuated by CGRP. The effect of CGRP on cardiac fibroblasts was inhibited by CGRP8-37, a selective antagonist of CGRP receptor. CONCLUSION: CGRP is able to protect cardiac fibroblasts against isoprenaline-induced proliferation and collagen expression, which might be related to the down-regulation of CTGF expression through inhibition of ROS production.

Dexrazoxane provided moderate protection in a catecholamine model of severe cardiotoxicity.

Positive effects of dexrazoxane (DEX) in anthracycline cardiotoxicity have been mostly assumed to be associated with its iron-chelating properties. However, this explanation has been recently questioned. Iron plays also an important role in the catecholamine cardiotoxicity. Hence in this study, the influence of DEX on a catecholamine model of acute myocardial infarction (100 mg/kg of isoprenaline by subcutaneous injection) was assessed: (i) the effects of an intravenous dose of 20.4 mg/kg were analyzed after 24 h, (ii) the effects were monitored continuously during the first two hours after drug(s) administration to examine the mechanism(s) of cardioprotection. Additional in vitro experiments on iron chelation/reduction and influence on the Fenton chemistry were performed both with isoprenaline/DEX separately and in their combination. DEX partly decreased the mortality, reduced myocardial calcium overload, histological impairment, and peripheral haemodynamic disturbances 24 h after isoprenaline administration. Continuous 2 h experiments showed that DEX did not influence isoprenaline induced atrioventricular blocks and had little effect on the measured haemodynamic parameters. Its protective effects are probably mediated by inhibition of late myocardial impairment and ventricular fibrillation likely due to inhibition of myocardial calcium overload. Complementary in vitro experiments suggested that iron chelation properties of DEX apparently did not play the major role.

Autoantibodies against cardiac ß(1)-adrenoceptor do not affect the low-affinity state ß(1)-adrenoceptor-mediated inotropy in rat cardiomyocytes.

Circulating autoantibodies directed against the 2nd extracellular loop (EL-2) of ß(1)-adrenoceptors (ß(1)-AABs) have been detected in the serum of patients with various cardiovascular pathologies. ß(1)-AABs induce agonistic, positive inotropic effects via ß(1)-adrenoceptors (ß(1)ARs). In the mammalian heart, ß(1)-AR can exist in 2 distinct activated configurations (the so-called high- and low-affinity states). The aim of the present study was to investigate whether the action of ß(1)-AAB is dependent on the affinity state of ß(1)AR in isolated ventricular cardiomyocytes of adult Wistar rats. Immunoglobulin G (IgG) containing ß(1)-AAB obtained from animals immunized with a peptide corresponding to the EL-2 of human ß(1)-AR, caused a dose-dependent increase in cell shortening. Isoproterenol-induced inotropy was significantly reduced in cardiomyocytes that had been preincubated with IgG containing ß(1)-AAB and in cardiomyocytes isolated from immunized rats. The negative effects of preincubation with IgG containing ß(1)-AAB on the response to isoproterenol was inhibited in the presence of bisoprolol. CGP 12177A and pindolol-induced inotropy was not affected by IgG preincubation or immunization. No detectable inotropic effect of cell shortening was obtained with IgG containing ß(1)-AAB in the presence of propranolol and 3-isobutyl-1-methylxanthine. The present study demonstrates that ß(1)-AABs have no agonist/antagonist-like effects upon low-affinity state ß(1)-ARs. This result indicates that ß(1)-AABs recognize and stabilize the high-affinity state, but are unable to stabilize and (or) induce the low-affinity state receptor.

Genistein prevents isoproterenol-induced cardiac hypertrophy in rats.

Genistein, an isoflavone and a rich constituent of soy, possesses important regulatory effects on nitric oxide (NO) synthesis and oxidative stress. Transient and low release of NO by endothelial nitric oxide synthase (eNOS) has been shown to be beneficial, while high and sustained release by inducible nitric oxide synthase (iNOS) may be detrimental in pathological cardiac hypertrophy. The present study was designed to evaluate whether genistein could prevent isoproterenol-induced cardiac hypertrophy in male Wistar rats (150-200 g, 10-12 weeks old) rats. Isoproterenol (5 mg·(kg body weight)(-1)) was injected subcutaneously once daily for 14 days to induced cardiac hypertrophy. Genistein (0.1 and 0.2 mg·kg(-1), subcutaneous injection once daily) was administered along with isoproterenol. Heart tissue was studied for myocyte size and fibrosis. Myocardial thiobarbituric acid reactive substances (TBARS), glutathione (GSH), superoxide dismutase (SOD), catalase levels, and 1-OH proline (collagen content) were also estimated. Genistein significantly prevented any isoproterenol-induced increase in heart weight to body weight ratio, left ventricular mass (echocardiographic), myocardial 1-OH proline, fibrosis, myocyte size and myocardial oxidative stress. These beneficial effects of genistein were blocked by a nonselective NOS inhibitor (L-NAME), but not by a selective iNOS inhibitor (aminoguanidine). Thus, the present study suggests that the salutary effects of genistein on isoproterenol-induced cardiac hypertrophy may be mediated through inhibition of iNOS and potentiation of eNOS activities.

The function of calcineurin and ERK1/2 signal in the antihypertrophic effects of kappa-opioid receptor stimulation on myocardial hypertrophy induced by isoprenaline.

The aim of the present study, performed in an in vitro model of cardiac hypertrophy, was to examine the possible function of calcineurin and ERK1/2 in the inhibitory effects of kappa-opioid receptor stimulation on Ca2+ transients and myocardial hypertrophy induced by beta1-adrenoceptor stimulation. We determined the effects of trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]-benzeneacetamid methanesulfonate salt (U50,488H), a selective kappa-opioid receptor agonist, on the enhancement of spontaneous Ca2+ transients and the induction of hypertrophy by isoprenaline, a beta-adrenoceptor agonist, in cultured neonatal ventricular myocytes. Total protein content, [3H]leucine incorporation and cell size were used as indices of hypertrophy; calcineurin activity and phospho-ERK1/2 level were determined by immunoblotting. Isoprenaline (10 micromol x L(-1)) increased all the three indices of hypertrophy, Ca2+ transients, calcineurin activity and the level of phospho-ERK1/2. The effects of isoprenaline were abolished by 1 micromol x L(-1) U50,488H in the absence but not in the presence of nor-binaltorphimine, a kappa-opioid receptor antagonist. The inhibitory effects of U50,488H were reproduced by cyclosporine-A, an inhibitor of calcineurin, U0126, the inhibitor of ERK1/2 and verapamil, a L-type Ca2+ channel antagonist. In addition, suppression of calcineurin activity by cyclosporine-A was associated with modest suppression of ERK1/2 phosphorylation. Meanwhile, suppression of ERK1/2 phosphorylation by U0126 was associated with modest suppression of calcineurin activity. In conclusion, the inhibitory effects of kappa-opioid receptor stimulation involved calcineurin and ERK1/2, and the two signaling pathways showed interaction in the mechanism of antihypertrophic effects afforded by kappa-opioid receptor stimulation.

Reduction of isoprenaline-induced myocardial TGF-ß1 expression and fibrosis in osthole-treated mice.

Peroxisome proliferator-activated receptor (PPAR) α and PPARγ ligands can attenuate myocardial fibrosis. Osthole, an active constituent isolated from the fruit of Cnidium monnieri (L.) Cusson, may be a dual PPARα/γ agonist, but there has been no report on its effect on myocardial fibrosis. In the present study, we investigated the inhibitory effect of osthole on myocardial fibrotic formation in mice and its possible mechanisms. A mouse model with myocardial fibrosis was induced by hypodermic injection of isoprenaline while the mice were simultaneously treated with 40 and 80 mg/kg osthole for 40 days. After the addition of osthole, the cardiac weight index and hydroxyproline content in the myocardial tissues were decreased, the degree of collagen accumulation in the heart was improved, and the downregulation of myocardial PPARα/γ mRNA expression induced by isoprenaline was reversed. Moreover, the mRNA expression of transforming growth factor (TGF)-ß1 and the protein levels of nuclear factor (NF)-κB and TGF-ß1 in the myocardial tissues were decreased. These findings suggest that osthole can prevent isoprenaline-induced myocardial fibrosis in mice, and its mechanisms may be related to the reduction of TGF-ß1 expression via the activation of PPARα/γ and subsequent inhibition of NF-κB in myocardial tissues.

Interaction of Semecarpus anacardium L. with propranolol against isoproterenol induced myocardial damage in rats.

With a view to evaluate the cardioprotective effect of ethanolic extract of S. anacardium nut and the possible interaction with propranolol against isoproterenol induced myocardial damage in rats, female Sprague-Dawley rats were pre-treated with propranolol (10 mg/kg for 7 days), low and high doses of S. anacardium (100 and 500 mg/kg for 21 days) and their combination orally and subsequently subjected to isoproterenol administration (150 mg/kg, sc) for two consecutive days. The influence of prophylactic treatment was analysed by quantification of biomarkers and antioxidants, electocardiographic parameters and histopathological observations. The activities of lactate dehydrogenase and creatinine phosphokinase-MB were reduced in serum and raised in heart tissue with concurrent elevation in superoxide dismutase and catalase activities as well as reduction in thiobarbituric acid reactive species levels significantly in all treated groups compared to isoproterenol group. Similarly, electrocardiographic changes were restored to normalcy in all treated groups. To conclude, combination of high dose of S. anacardium with propranolol was found to be most effective in alleviating the abnormal conditions induced by isoproterenol.

Calcitonin gene-related peptide suppresses isoprenaline-induced cardiomyocyte apoptosis through regulation of microRNA-1 and microRNA-133a expression.

OBJECTIVE: To explore the inhibitory effect of calcitonin gene-related peptide (CGRP) on cardiomyocyte apoptosis and the underlying mechanism. METHODS: In cultured rat cardiomyocytes, apoptosis was induced by the incubation of isoprenaline (10(-5) mol/L) for 48 h. CGRP (10(-8) or 10(-7) mol/L) was administrated for 1 h before incubating isoprenaline to evaluate its effect on cardiomyocyte apoptosis. At the end of the drug treatment, the rate of apoptotic cells and intracellular reactive oxygen species (ROS) were determined, and RNA was extracted to examine the expression of microRNA-1 and microRNA-133a. RESULTS: Isoprenaline significantly increased the rate of apoptotic cells and intracellular ROS production concomitantly with the increased microRNA-1 expression and the decreased microRNA-133a expression, which were inhibited by pretreatment with CGRP. The effects of CGRP were reversed by CGRP receptor antagonist. CONCLUSION: CGRP can inhibit the isoprenaline-induced cardiomyocyte apoptosis. The beneficial effect of CGRP is related to regulating microRNA-1 and microRNA-133a expression through the prevention of isoprenaline-induced ROS production.

The cardioprotective effect of microRNA-103 inhibitor against isoprenaline-induced myocardial infarction in mice through targeting FADD/RIPK pathway.

OBJECTIVE: The current study investigates the effect of the innovative phosphorothioate modified backbone locked nucleic acid (LNA) of microRNA-103 (miR-103) specifically designed for systemic delivery in the silencing of miR-103 in experimentally induced myocardial infarction (MI). MicroRNA-103 is a small non-coding RNA which regulates Fas-associated protein with death domain (FADD) gene expression, which is a negative regulator for necroptosis occurs during the progression of MI. MATERIALS AND METHODS: Experimental male mice were allocated into three groups; the first group received normal saline, the second group was injected with isoprenaline and served as the infarcted control, while the third group was treated with LNA miR-103 power inhibitor before isoprenaline injection. Blood and heart samples were used for biochemical analysis of miR-103, FADD, receptor-interacting protein kinase (RIPK), nuclear factor-κß, tumor necrosis factor-α, interleukin-6, troponin-I and creatine kinase-MB (CK-MB) as well as the histological examination of heart tissue. RESULTS: The treated mice showed marked improvement in the troponin-I and CK-MB levels with almost normal histological structure of heart tissue. Significant inhibition of miR-103 accompanied by increased FADD expression and markedly decreased expression of the other biomarkers were observed in the hearts of the treated mice. CONCLUSIONS: LNA miR-103 inhibitor is a potent cardioprotective agent and can be a promising treatment against MI through targeting FADD/RIPK pathway.

Melatonin protects against isoproterenol-induced myocardial injury in the rat: antioxidative mechanisms.

The present study was undertaken to explore the protective effect of melatonin against isoproterenol bitartrate (ISO)-induced myocardial injury in rat. Treatment of rats with ISO increased the level of lipid peroxidation products and decreased the reduced glutathione levels in cardiac tissue indicating that this synthetic catecholamine induces oxidative damage following oxidative stress. Pretreatment of ISO-injected rats with melatonin at a dose of 10 mg/kg body weight, i.p. prevented these changes. Additionally, melatonin also restored the activities and the levels of antioxidant enzymes which were found to be altered by ISO treatment. Treatment of rats with ISO resulted into an increased generation of hydroxyl radicals with melatonin pretreatment significantly reducing their production. Finally, treatment of rats with ISO caused a lowering of systolic pressure with reduced cardiac output and diastolic dysfunction whereas melatonin pretreatment significantly restored many of these parameters to normal. The findings document melatonin's ability to provide cardio protection at a low pharmacological dose. Melatonin has virtually no toxicity which raises the possibility of this indole being a therapeutic treatment for ischemic heart disease.

The protective effect of piperine against isoproterenol-induced inflammation in experimental models of myocardial toxicity.

Myocardial infarction (MI) eventually exacerbates inflammatory response due to the release of inflammatory and pro-inflammatory factors. The aim of this study is to explore the protective efficacy of piperine supplementation against the inflammatory response in isoproterenol (ISO)-induced MI. Masson Trichome staining was executed to determine myocardial tissue architecture. Immunohistochemistry was performed for IL-6, TNF-α. RT-PCR studies were performed to ascertain the gene expression of IL-6, TNF-α, iNOS, eNOS, MMP-2, MMP-9, and collagen-III. Western blotting was performed to determine expression of HIF-1α, VEGF, Nrf-2, NF-ƙB, Cox-2, p-38, phospho-p38, ERK-1/2, phospho-ERK-1/2, and collagen-I. HIF-1α, VEGF, and iNOS expression were significantly upregulated with concomitant decline in eNOS expression in the heart myocardial tissue of rats received ISO alone whereas piperine pretreatment prevented these changes in ISO administered rats. Current results revealed ROS-mediated activation of MAPKs, namely, p-p38, p-ERK1/2 in the heart tissue of ISO administered group. Piperine pretreatment significantly prevented these changes in ISO treated group. NF-κB is involved in the modulation of gene expressions responsible for tissue repair. ISO-induced NF-κB-p65 expression was significantly reduced in the group pretreated with piperine and mitigated extent of myocardial inflammation. A significant increase in cardiac fibrosis upon ISO treatment was reported due to the increased hydroxyproline content, MMP-2 & 9 and upregulation of collagen-I protein compared to control group. All these cardiac hypertrophy markers were decreased in 'piperine pretreated ISO administered group' compared to group received ISO injection. Current findings concluded that piperine as a nutritional intervention could prevent inflammation of myocardium in ISO-induced MI.