Isoproterenol-induced Myocardial Injury Research Articles

Sulforaphane Attenuates Isoproterenol-Induced Myocardial Injury in Mice.

The development of isoproterenol- (ISO-) induced oxidative stress in the myocardium results in myocardial necrosis. Sulforaphane (SFN-0.4% of sulforaphane from standardized broccoli sprout extract) possesses chemoprotective, antidiabetic, and antibacterial activities and is also active against cardiovascular-related problems due to its antioxidant properties. This study was designed to investigate the cardioprotective effect of SFN against isoproterenol-induced myocardial injury in mice. Healthy male Swiss albino mice weighing 20–30 g were used in this study. These mice were randomly divided into five groups (n = 6). All the mice in the experimental groups received isoproterenol (5 mg/kg bw, via i.p.) consecutively for 2 days. The mice were treated with SFN (4 mg/kg bw) and α-tocopherol (TCF) (10 mg/kg bw) by oral gavage for 1-7 days as pre- and posttreatment for the prophylactic and treatment groups, respectively. On day 10, the following parameters were studied: heart weight to body weight ratio, antioxidant parameters, and cardiac markers; and mitochondrial enzymes were estimated for cardioprotection. Administration of isoproterenol in mice showed an increased level of serum cardiac markers and heart mitochondrial ATPase enzymes. An increased level of myocardial thiobarbituric acid-reactive substance and decreased levels of endogenous antioxidant enzymes indicated that oxidative stress is induced by isoproterenol in the myocardium. The administration of SFN in mice restored the levels of all biochemical parameters to near-normal levels. Histopathological studies further confirmed the protective effect of sulforaphane. This study concluded that treatment with SFN boosts the endogenous antioxidant activity and prevents isoproterenol-induced myocardial injury.

Cardioprotective Role of Theobroma cacao against Isoproterenol-Induced Acute Myocardial Injury.

Antioxidants are beneficial in myocardial infarction (MI). It is suggestive that Theobroma cacao (TC) with rich antioxidant properties can be of health benefits in myocardial injury. The study investigated the effect of Theobroma cacao on cardioprotection in isoproterenol-induced myocardial infarction in rats. Male Wistar rats divided into four groups of 6 rats were used for the study. In group 1, 0.9% normal saline placebo was administered via oral gavage to the control. Group 2 was the MI induced group that was given 100 mg/kg body weight isoproterenol subcutaneously twice at an interval of 24 hours. Group 3 was administered TC for 2 weeks at 100 mg/kg bodyweight via the oral route. Group 4 was pretreated with TC (100 mg/kg) via oral route for 2 weeks, immediately followed by the administration of 100 mg/kg body weight isoproterenol subcutaneously twice at an interval of 24 hours. The rats were sacrificed using chloroform anesthesia, and blood samples collected via cardiac puncture. The serum was analyzed for troponin level, lactate dehydrogenase (LDH), and malondialdehyde (MDA) level. The serum troponin, LDH, and MDA levels were found to be significantly (p<0.01) increased in the MI group compared with the control. Pretreatment with TC before MI induction significantly (p<0.01) prevented increased serum troponin, LDH, and MDA levels when compared with the MI group. There was also a significant (p<0.01) decrease in MDA in the TC group compared with the control. These results suggest that Theobroma cacao protects against isoproterenol-induced myocardial injury, possibly by preventing oxidative stress and consequent lipid peroxidation.

Cardioprotective effect exerted by Timosaponin BⅡ through the regulation of endoplasmic stress-induced apoptosis

BackgroundTimosaponin BⅡ (TBⅡ), one of the primary bioactive compounds from Anemarrhena asphodeloides Bunge, possesses potential cardioprotective effects. However, the mechanism underlying TBⅡ-mediated cardioprotection, especially the involvement of endoplasmic reticulum stress, remains largely unknown. PurposeThis study was designed to evaluate the role of TBⅡ in myocardial injury protection and explore its possible mechanisms. MethodsIn vivo models of isoproterenol-induced myocardial injury and H2O2-induced cytotoxicty were established to investigate the effect of anti-myocardial injury of TBⅡ. The potential mechanisms were investigated in vitro and in vivo using multiple detection methods like electrocardiography, histo-pathological examination, JC-1 staining, TUNEL staining, ELISA technology, and western blot analysis. ResultsIn vivo study revealed that TBⅡ improved electrocardiography and heart vacuolation, reduced myocyte apoptosis, and improved the antioxidant potential. In vitro investigation demonstrated that TBⅡ pretreatment inhibited ER stress-mediated apoptosis pathways. Further investigation of the underlying mechanisms revealed that TBⅡ prevented H2O2-induced H9c2 cardiomyocytes injury by the PI3K/Akt pathways, whereas the addition of LY294002, the pharmacologic antagonist of PI3K, attenuated TBⅡ-induced expression of apoptotic protein and cytoprotective effects. ConclusionThese results suggested that TBⅡ protects against myocardial injury in vitro and enhances cellular defense capacity by inhibiting ER stress-mediated apoptosis pathways in vivo by activating the PI3K/Akt pathways.

Putative anti-inflammatory, antioxidant, and anti-apoptotic roles of the natural tissue guardian methyl palmitate against isoproterenol-induced myocardial injury in rats

BackgroundMyocardial injury is considered as a worldwide main cause of morbidity and mortality. The present study aimed to investigate the probable cardioprotective activity of the naturally occurring endogenous fatty acid ester methyl palmitate (MP) against isoproterenol (ISO)-induced myocardial injury in rats and the possible underlying molecular mechanisms. The study was carried out in two consecutive sets of experiments; the first set screened the cardioprotective dose of MP in ISO-intoxicated rats. In the second set, forty male Sprague Dawley rats received either MP (150 mg/kg, p.o) three times/week for 2 weeks and/or 2 consecutive doses of ISO separated by 24 h (85 mg/kg, s.c) on the 13th and 14th days. Different cardiotoxicity and oxidative stress markers were assessed. Furthermore, endothelial nitric oxide synthase (eNOS) levels were determined. For detection of apoptosis, Bax, Bcl-2, and caspase 3 were estimated. To assess inflammation, toll-like receptor 4 (TLR-4) and tumor necrosis factor-alpha (TNF-α) were measured using ELISA. Meanwhile, nuclear factor kappa B (NF-kB) and cyclooxygenase-2 (COX-2) were detected immunohistochemically.ResultsPretreatment with MP significantly ameliorated the cardiotoxicity and oxidative stress markers. It also markedly elevated eNOS content, decreased apoptotic marker expression, and mitigated TLR-4 activation and other inflammatory markers. Electrocardiography and histopathological examination also confirmed the cardioprotective effect of MP.ConclusionThe findings of this study indicated that MP possesses a potent cardioprotective activity against ISO-induced myocardial injury through its significant antioxidant, anti-apoptotic, anti-inflammatory, and vasodilatation activities.Graphical abstract

Role of nitric oxide in mediating the cardioprotective effect of agomelatine against isoproterenol-induced myocardial injury in rats.

Myocardial infarction (M/I) is a common cause of mortality worldwide. Agomelatine (AGO), a potent melatonin receptor agonist, proved to have ananti-inflammatory and antioxidant effect. The present study aimed to explore the cardioprotective effect of AGO on isoproterenol (ISO)-induced myocardial injury in a rat model and determine the role of nitric oxide (NO) in mediating this beneficial effect. Rats were randomly divided into 6 groups and treated for 12days. Group 1, control, received normal saline. Group 2, ISO group, received ISO (100mg/kg, i.p.) in 11th and 12th days. Group 3, positive control group, received atenolol (100mg/kg/day) + ISO. Group 4, AGO-treated group, received AGO (80mg/kg/day) + ISO. Group 5, L-NNA + ISO, received L-NG-nitro arginine (L-NNA) (25mg/kg, orally) + ISO. Group 6, AGO + L-NNA + ISO, co-treated with AGO + ISO + L-NNA. Serum cardiac enzymes and cardiac tissue oxidative stress parameters were assessed along with histopathological evaluation. Gene expression quantification of nuclear factor erythroid 2 (Nrf-2) and heme oxygenase-1 (HO-1) were assessed. Immunoexpression of inducible NO synthase (iNOS) and caspase-3 were evaluated. The outcomes proved that ISO significantly increased serum cardiac enzymes, with histopathological changes of myocardial tissue along with a major increase in oxidative, inflammatory, and nitrosative stress, besides a reduction in cardiac Nrf-2 and HO-1 gene expressions with marked myocardial cell apoptosis. However, pretreatment with AGO significantly reversed these profound ISO myocardial damaging effects. AGO protects against ISO-induced myocardial injury through its antioxidant, anti-inflammatory, and anti-apoptotic effects with modulation of NOS enzymes.

Remifentanil attenuates cardiac dysfunction, lipid peroxidation and immune disorder in rats with isoproterenol-induced myocardial injury via JNK/NF-KB p65 inhibition.

BackgroundMyocardial injury caused by myocardial ischemia (MI) is still a severe condition that can result in apoptosis, oxidative stress, and inflammation. Remifentanil is a selective, ultra-short-acting, µ-opioid receptor agonist opioid. It can improve sinusoidal heart rate patterns in the fetus, for bupivacaine-induced cardiotoxicity, and with lipopolysaccharide (LPS)-induced cardiomyocytes injuries. This study aimed to explore the cardioprotective effects of remifentanil in MI model rats.MethodsSprague Dawley (SD) rats were split into five groups at random, including a control group, Isop group, low-dose remifentanil treatment group (10 µg/kg), medium-dose remifentanil treatment group (20 µg/kg), and a high-dose remifentanil treatment group (40 µg/kg). The MI model was achieved by subcutaneously injecting rats with isoproterenol (85 mg/kg) for two consecutive days. With the expression of apoptotic molecules, myocardial systolic function index, inflammation, antioxidant enzymes, and the myocardial enzyme taken into account, the data was analyzed.ResultsAfter treatment with remifentanil, the left ventricular wall thickness (LVWT), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), fraction shortening (FS), and heart rate (HR) were significantly increased in comparison with the Isop group. Creatine kinase-MB (CK-MB), Mb, and cTnl expressions were decreased. Meanwhile, the levels of cleaved caspase-3 and caspase-9 were decreased. Remarkably, the levels of reactive oxidative species (ROS), malondialdehyde (MDA), and lactate dehydrogenase (LDH) were observed to be repressed, while the levels of superoxide dismutase (SOD) was significantly increased. More importantly, the levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, and interferon (IFN)-γ were decreased.ConclusionsRemifentanil has significant potential as a therapeutic intervention strategy for ameliorating myocardial injury after MI and these findings provide the rationale for further clinical studies.

Cardioprotection of cortistatin against isoproterenol-induced myocardial injury in rats.

BackgroundThe present study was designed to examine whether cortistatin (CORT) could protect rats from myocardial injury induced by subcutaneously injecting isoproterenol (ISO) and to clarify the possible mechanisms.MethodsMale Sprague-Dawley (SD) rats were placed at random into four groups: the control group, the ISO group, the ISO + CORT 25 µg/(kg·d) group, and the ISO + CORT 50 µg/(kg·d) group. Rat models of myocardial injury were established with the subcutaneous (s.c.) injections of 85 mg/kg ISO for 2 days. In the ISO+ CORT 25 µg/(kg·d) group and ISO+ CORT 50 µg/(kg·d) group, rats were given s.c. injections of CORT 25 µg/(kg·d) and CORT 50 µg/(kg·d) on the day before ISO, 3 days, respectively. Serum malondialdehyde (MDA) content, lactate dehydrogenase (LDH) activity, and creatine kinase isoenzyme (CK-MB) activity were measured by corresponding test kits. Western blot was applied to evaluate the expression of endoplasmic reticulum stress-related protein glucose regulatory protein 78 (GRP78), enhancer-binding protein homologous protein (CHOP), cysteinyl aspartate specific proteinase-12 (caspase-12), LC3-II, Beclin-1, and p62 in the rat myocardium.ResultsCORT alleviated the increased enzyme activities of serum LDH and CK-MB, and content of MDA (a typical marker of lipid peroxidation) in rats induced by ISO. CORT also prevented pathological myocardial injury in rats induced by ISO. Moreover, CORT attenuated the increased protein levels of GRP78, CHOP, and caspase-12, and reduced the increase of LC3-II, LC3-II/I, Beclin-1, and p62 in rats induced by ISO.ConclusionsThese data demonstrate that CORT can attenuate ISO-induced acute myocardial injury in rats likely by reducing lipid peroxidation, and inhibiting endoplasmic reticulum stress and autophagy. This supports CORT as a potentially being a new target for preventing and treating myocardial injury and its related disease.

Attenuation of ROS-mediated myocardial ischemia-reperfusion injury by morin via regulation of RISK/SAPK pathways.

Oxidative stress plays an important role in the pathogenesis of myocardial ischemia-reperfusion (IR) injury. Morin, a bioflavonoid, has demonstrated antioxidant, anti-inflammatory and other diverse pharmacological activities in various experimental models such as isoproterenol-induced myocardial injury, doxorubicin-induced cardiotoxicity and neurotoxicity, as well as cisplatin-induced nephrotoxicity. Thus, this study aimed to evaluate the effect of morin in myocardial IR injury model and its underlying mechanisms. To accomplish this, male albino Wistar rats were pre-treated with morin (40 and 80mg/kg; po) for 28days and on 29th day, rats experienced 45-min myocardial ischemia followed by 60-min reperfusion. In comparison to IR-control group, morin pre-treatment significantly normalized hemodynamic parameters, restored antioxidant status, improved pathological changes, reduced the release of cardiac injury markers, inhibited inflammation (TNF-α/IL-6/NFκB/IKKβ) and apoptosis (increased Bcl-2, decreased Bax/Caspase-3 and TUNEL positivity) in the myocardium. This improvement in antioxidant, inflammation and anti-apoptosis markers could be due to downregulation of SAPK (p38/JNK) pathway and upregulation of survival kinase, i.e. RISK pathway (ERK/eNOS) in the myocardium. Thus, morin attenuated myocardial IR injury in rats by regulation of RISK/SAPK pathways.

The effects of resveratrol treatment on caveolin-3 expression and Na+/K+ ATPase activity in rats with isoproterenol-induced myocardial injury.

OBJECTIVE:The present study aims to investigate the therapeutic effects of resveratrol (RES) on isoproterenol (ISO) induced myocardial injury rat model.METHODS:Catecholamine-induced heart damage was induced by ISO treatment for 30 days. The rats were divided into four groups as follows: the control group received saline, the ISO group received 5.0 mg/kg ISO, the RES group received 10 mg/kg RES, and the ISO-RES group received 10 mg/kg RES and 5 mg/kg ISO treatments for 30 days. Following echocardiographic measurements and body weight recorded, the rats were decapitated. Plasma and cardiac tissue samples obtained by decapitation were analyzed using biochemical, histopathological, molecular and immunohistochemical methods.RESULTS:In the ISO group, Na+/K+ ATPase activity and ATP content, GSH, and caveolin-3 levels were low. LDH, CK and lysosomal enzyme activities, MDA level, and MPO activity were found to be high. It was determined that GSH and MDA levels and MPO, Na+/K+ ATPase activity, ATP content caveolin-3 levels changes that arose from ISO treatment were suppressed by RES treatment.CONCLUSION:RES treatment has ameliorated all the functional and biochemical parameters. The results obtained in this study suggest that RES is a promising supplement against catecholamine exposure as it improves antioxidant defense mechanisms in the heart. In the light of above-mentioned data, RES can be assumed as a promising agent in ameliorating the oxidative injury of the myocardium.

Qi-Li-Qiang-Xin Alleviates Isoproterenol-Induced Myocardial Injury by Inhibiting Excessive Autophagy via Activating AKT/mTOR Pathway.

Background: Apoptosis and autophagy are two important patterns of cell death in the process of heart failure. Qi-Li-Qiang-Xin (QLQX), a traditional Chinese medicine, has been frequently used in the treatment of chronic heart failure (CHF) in China. However, the potential effect of QLQX on autophagy has not been reported. In this study, we aimed to investigate whether QLQX alleviated isoproterenol (ISO)-induced myocardial injury through regulating autophagy. Methods: The rapid identification of chemical ingredients of QLQX was performed by UPLC-Q-TOF-MS, and the contents of major constituents in QLQX were also measured by UPLC-Q-TOF-MS. ISO was used to induce myocardial injury in H9c2 cardiomyocytes and SD rats. In vivo, cardiac function was evaluated by echocardiography and cardiac structure was observed by HE and Masson staining. Expressions of Bcl-2, Bax, LC3, P62, AKT, p-AKT, mTOR, and p-mTOR were detected by western blotting. In vitro, H9c2 cells were pretreated with QLQX for 3 h before ISO (80 µM, 48h) addressed. Cell viability, LDH and CK-MB release, apoptosis ratio, and the level of autophagy were measured. Western blotting was also performed to detected related protein expressions. Result: In vivo, treatment by QLQX significantly improved cardiac function and alleviated ISO-induced myocardial structural damage. In addition, QLQX markedly decreased apoptosis and inhibited autophagic activity, accompanied by activating the AKT/mTOR pathway. In vitro, the increased cell apoptosis induced by ISO was paralleling with the gradually increasing level of autophagy. Furthermore, 3-MA, an autophagic inhibitor, could block ISO-induced autophagy in H9c2 cells. Our results suggested that both QLQX and 3-MA treatment could decrease cell death induced by ISO, implying that QLQX protected against ISO-induced myocardial injury possibly by inhibiting excessive autophagy-mediated cell death. In addition, blockage of AKT signaling by an AKT inhibitor, capivasertib, could reduce the effect of QLQX on inhibiting ISO-induced apoptosis and autophagy-mediated cell death. Conclusion: QLQX could alleviate ISO-induced myocardial injury by inhibiting apoptosis and excessive autophagy-mediated cell death via activating the AKT/mTOR pathway.

Transcriptomics and metabolomics reveal the cardioprotective effect of Compound Danshen tablet on isoproterenol-induced myocardial injury in high-fat-diet fed mice.

Compound Danshen tablet, an herbal preparation consisting of salviae miltiorrhizae, notoginseng and borneolum, is extensively employed clinically to treat angina pectoris, coronary arteriosclerosis and significantly improve microcirculation. To reveal the potential underlying cardioprotective mechanism(s) in isoproterenol-induced myocardial injury in high-fat-diet fed mice. Cardiac transcriptomics was analyzed by Illumina mRNA-Seq sequencing. The restored cardiovascular diseases (CVD)-related genes by Compound Danshen tablet were validated by quantitative real time polymerase chain reaction (qRT-PCR). Furthermore, Cardiac metabolomics were also performed using gas chromatography-mass spectrometry. From the transcriptomics study, we found the levels of 24 up-regulated and 44 down-regulated genes in the control compared to model groups. Among them, seven gene levels were restored by treatment of Compound Danshen tablet. Four CVD-related genes at the mRNA level (Sprr1a, Ppp1r3c, Bmp10 and Hspa1b) were validated successfully by qRT-PCR. From the metabolomics study, 37 differentially expressed metabolites were identified between the control and model groups. Among them, 21 metabolites were restored by treatment of Compound Danshen tablet. These altered metabolites are involved in glucose metabolism, fatty acid metabolism and amino acid metabolism. These genes and metabolites might provide clues for further molecular mechanistic study of Compound Danshen tablet.

Ameliorative effects of cerebrolysin against isoproterenol-induced myocardial injury in male rats

AimsMyocardial injury (MI) is the principal cause of death from cardiovascular disease (CVD). The present study was conducted to investigate the ameliorative and antioxidant effects of cerebrolysin (CBL) on isoproterenol-induced MI in rats. MethodsMI was induced in the rats by subcutaneously injecting 100 mg/kg of isoproterenol (ISO) in the first two days. The serum levels of creatine phosphokinase (CK-MB) and cardiac troponin I (cTnI) were measured on the third day to confirm MI. The post-treatment involved intraperitoneally injecting 5 ml/kg of CBL for 7 days. Nitric oxide (NO), malondialdehyde (MDA) in the heart tissue and catalase (CAT) and serum levels of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were measured on the 10th day using the enzyme-linked immunosorbent assay (ELISA). Histopathological examinations of the heart tissue were also performed. FindingsThe present results suggested significant increases in CK-MB, cTnI, MDA and NO. A significant decrease was also observed in the ISO-treated rats in certain antioxidant enzymes, including CAT and GPX. CBL administration showed a significant ameliorative increase against the oxidative ISO-induced damage. Moreover, the histopathological findings showed lower levels of the infiltration of inflammatory cells and edema and vascular proliferation in the CBL-treated rats. SignificanceThe present histopathological and biochemical findings attributed antioxidant properties to CBL in the rat myocardium and suggested protective effects on ISO-induced MI.

Experimental justification of the effectiveness of cord blood stem cell transplantation in chronic myocardial injury

Purpose of the study. Determination of transplantation efficiency of cord blood stem cells (CB SC) for damage to the myocardium and assessment of the repair of its disturbed functions in the experiment.&#x0D; Materials and methods. The experiment was conductedonmiceofthe FVBlineattheageof5 months, with a body weight of 25–30 g. Animals were divided into experimental groups of 5 animals in each. The animals of the study group were derived from the experiment before the SC suspension injection, after 2 days, 4 and 8 weeks after cell transplantation.&#x0D; Results. Analysis of morphofunctional changes after the introduction of cord blood cells in 4 and 8 weeks compared to the original state (3 weeks after modeling of the isoproterenol induced myocardial injury model) has established a clear tendency to improve the investigated parameters. The confirmed phenomenon of self-referral of cord blood nto the lesion zone proves the expediency of transplantation by intravenous injection of a suspension of CB SC. It has been established that transplantation of CB SC causes a temporary deterioration of morphofunctional features, which may be a manifestation of the body's response to xenotransplantation. The CB SC transplantation has a positive effect on the isoproterenol-induced myocardial injury model.&#x0D; Conclusions: 1. Accumulation of CBSC in the zone of injury after transplantation, proved by experimental research. 2. CB SC transplantation accelerates the processes of myocardial regeneration on the model of injury in laboratory animals. 3. Intravenous injection of the CB SC suspension to the models of myocardial injury proved to be effective. 4. The experimental results obtained can serve as the basis for further clinical studies in patients with heart failure.

Cardioprotective effects of cerebrolysin on the lesion severity and inflammatory factors in a rat model of isoproterenol-induced myocardial injury.

Myocardial injury (MI) is an important heart condition and a major cause of morbidity and mortality worldwide. The current study was designed to investigate the cardioprotective effects of cerebrolysin (CLY) on the lesion severity and inflammatory factors in male rats using isoproterenol (ISO)-induced MI model. MI in rats was induced by injecting ISO (100 mg/kg) subcutaneously (sc) on the first 2 days. Then, CLY (5 ml/kg) was injected intraperitoneally (ip) post-treatment for 7 days. On the 3rd day, creatine phosphokinase (CK-MB) and cardiac troponin I (cTnI) levels in serum and, on the 10th day, the TNF-α and IL6 levels in serum and heart tissue were measured by enzyme-linked immunosorbent assay (ELISA). Finally, the heart of each rat was dissected out and stained for histopathological examination. On the 3rd day, the serum CK-MB and cTnI levels in the ISO and CLY + ISO groups were significantly increased compared with that in the control and CLY + Sal groups. One week after the induction of MI, ISO administration showed a significant increase in the serum level of TNF-α in the ISO group compared with that in the control and CLY + Sal groups. Also, our findings showed only a moderate reduction in inflammatory cell infiltration and extent of edema following CLY treatment in the CLY + ISO group. Also, CLY induced vascular proliferation in the heart tissue. We conclude that the severity of pathological changes induced by ISO in MI (e.g. inflammation and edema) can be limited by CLY treatment.

Succinate induces aberrant mitochondrial fission in cardiomyocytes through GPR91 signaling

Altered mitochondrial metabolism acts as an initial cause for cardiovascular diseases and metabolic intermediate succinate emerges as a mediator of mitochondrial dysfunction. This work aims to investigate whether or not extracellular succinate accumulation and its targeted G protein-coupled receptor-91 (GPR91) activation induce cardiac injury through mitochondrial impairment. The results showed that extracellular succinate promoted the translocation of dynamin-related protein 1 (Drp1) to mitochondria via protein kinase Cδ (PKCδ) activation, and induced mitochondrial fission factor (MFF) phosphorylation via extracellular signal-regulated kinases-1/2 (ERK1/2) activation in a GPR91-dependent manner. As a result, enhanced localization of MFF and Drp1 in mitochondria promoted mitochondrial fission, leading to mitochondrial dysfunction and cardiomyocyte apoptosis. We further showed that inhibition of succinate release and GPR91 signaling ameliorated oxygen–glucose deprivation-induced injury in cardiomyocytes and isoproterenol-induced myocardial ischemia injury in mice. Taken together, these results showed that in response to cardiac ischemia, succinate release activated GPR91 and induced mitochondrial fission via regulation of PKCδ and ERK1/2 signaling branches. These findings suggest that inhibition of extracellular succinate-mediated GPR91 activation might be a potential therapeutic strategy for protecting cardiomyocytes from ischemic injury.

Cardioprotective effect of rosuvastatin against isoproterenol-induced myocardial infarction injury in rats.

Rosuvastatin, a member of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, exerts various pharmacological activities. This study evaluated the cardioprotective effect of rosuvastatin on isoproterenol-induced myocardial infarction injury in rats. A rat model of myocardial infarction injury was induced by isoproterenol(ISO) for 2consecutive days, rosuvastatin was administered for 8weeks. The levels of myocardial infarct size, aspartate transaminase(AST), alanine transaminase (ALT), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) activities, as well as malondialdehyde (MDA) levels, superoxide dismutase(SOD), glutathione peroxidase (GPX), catalase (CAT) activities and reduced glutathione (GSH) concentrations were determined. Hematoxylin and eosin staining was used to observe cardiac histological changes. Interleukin-1β (IL-1β) and IL-18 levels in heart tissues were detected with ELISA kits. The mRNA and protein levels of NOD-like receptor superfamily, pyrin domain containing3 (NLRP3) inflammasome were measured by qRT-PCR and western blot analysis, respectively. Our results showed that treatment with rosuvastatin reduced myocardial infract area, ameliorated histopathological alterations in myocardium, and decreased activities of myocardial injury marker enzymes in ISO-induced rats. In addition, rosuvastatin remarkably restored ISO-induced elevation of lipid peroxidation and decrease of antioxidants, significantly reduced myocardial pro-inflammatory cytokines concentrations in this animal model. Furthermore, rosuvastatin significantly inhibited the activation of NLRP3 inflammasome in this animal model. This study demonstrates that rosuvastatin significantly alleviates ISO-induced myocardial infarction injury. The mechanism is associated with attenuation of oxidative stress and inflammation, via the inhibition of NLRP3 inflammasome.

Ginsenoside Re Attenuates Isoproterenol-Induced Myocardial Injury in Rats.

Objective. Panax ginseng is widely used for treatment of cardiovascular disorders in China. Ginsenoside Re is the main chemical component of Panax ginseng. This study aimed to investigate the protective effect of Ginsenoside Re on isoproterenol-induced myocardial injury in rats. Methods. Male Wistar rats were orally given Ginsenoside Re (5, 20 mg/kg) daily for 7 days. Isoproterenol was subcutaneously injected into the rats for two consecutive days at a dosage of 20 mg/kg/day (on 6th and 7th day). Six hours after the last isoproterenol injection, troponin T level and creatine kinase-MB (CK-MB) activity were assayed. Histopathological examination of heart tissues was performed. The levels of malondialdehyde (MDA) and glutathione (GSH) in heart tissues were measured. The nuclear factor erythroid 2-related factor 2 (Nrf2) content in nucleus and the proteins of glutathione cysteine ligase catalytic subunit (GCLC) and glutathione cysteine ligase modulatory subunit (GCLM) in heart tissues were assayed by western blotting method. Results. Treatment with Ginsenoside Re at dose of 5, 20 mg/kg reduced troponin T level and CK-MB activity of rats subjected to isoproterenol. The cardioprotective effect of Ginsenoside Re was further confirmed by histopathological examination which showed that Ginsenoside Re attenuated the necrosis and inflammatory cells infiltration. Ginsenoside Re inhibited the increase of MDA content and the decrease of GSH in heart tissues. Moreover, the Nrf2 content in nucleus and the expressions of GCLC and GCLM were significantly increased in the animals treated with Ginsenoside Re. Conclusion. These findings suggested that Ginsenoside Re possesses the property to attenuate isoproterenol-induced myocardial ischemic injury by regulating the antioxidation function in cardiomyocytes.

Imaging of isoproterenol-induced myocardial injury with 18F labeled fluoroglucaric acid in a rat model

Positron emission tomography (PET) of myocardial infarction (MI) by infarct avid imaging has the potential to reduce the time to diagnosis and improve diagnostic accuracy. The objective of this work was to synthesize 18F–labeled glucaric acid (FGA) for PET imaging of isoproterenol-induced cardiomyopathy in a rat model. MethodsWe synthesized 18F–FGA by controlled oxidation of 18F–fluorodeoxy glucose (FDG), mediated by 4-acetamido-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) in presence of NaBr and NaOCl in highly-buffered reaction conditions. After ascertaining preferential uptake of 18F–FGA in necrotic as compared to normal H9c2 myoblasts, the biodistribution and circulation kinetics of 18F–FGA was assessed in mice. Moreover, the potential of 18F–FGA to image myocardial damage was investigated in a rat model of isoproterenol-induced cardiomyopathy. Isoproterenol-induced myocardial injury was verified at necropsy by tissue staining and plasma cardiac troponin levels. ResultsSynthesis of radiochemically pure 18F–FGA was accomplished by a 5 min, one step oxidation of 18F–FDG. Reaction yield was quantitative and no side-products were detected. Biodistribution studies showed rapid elimination from the body (ke = 0.83 h−1); the major organ of 18F–FGA accumulation was kidney. In the rat model, isoproterenol-treatment resulted in significant increase in cardiac troponin. PET images showed that the hearts of isoproterenol-treated rats accumulated significant amounts of 18F–FGA, whereas healthy hearts showed negligible uptake of 18F–FGA. Target-to-nontarget contrast for 18F–FGA accumulation became significantly more pronounced in 4 h images as compared to images acquired 1 h post-injection. Conclusion18F–FGA can be easily and quantitatively synthesized from ubiquitously available 18F–FDG as a precursor. The resultant 18F–FGA has a potential to serve as an infarct-avid agent for PET imaging of MI. Advances in knowledge and implications for patient care18F–FGA/PET will complement existing perfusion imaging protocols in therapeutic decision making, determination of revascularization candidacy and success, differentiation of ischemia from necrosis in MI, discrimination of myocarditis from infarction, and surveillance of heart transplant rejection.

Preventive effect of Agnucastoside C against Isoproterenol-induced myocardial injury

An iridoid glycoside, agnucastoside C (ACC) was isolated from the leaves of Moringa oliefera and its cardio protective potential was investigated in adult rats by examining the effects of this test compound, ACC at 30 mg/kg for 14 days in isoproterenol (100 mg/kg)-induced myocardial injury. Isoproterenol (ISO) administration induced the myocardial injury as evidenced by the altered ECG pattern with ST-segment elevation and an increase in the levels of cardiac injury markers including troponin-I, creatine kinase-MB, alanine transaminase, aspartate transaminase, lactate dehydrogenase; inflammatory markers, interleukine-6 and tumor necrosis factor. In this group, there was also an increase in cardiac lipid peroxidation and a decrease in cellular antioxidants. However, pretreatment with ACC maintained the normal ECG pattern and nearly normal levels of all the cardiac markers in ISO-induced animals. Electron microscopic and histological studies also showed marked reduction in ISO-induced cardiac damages including infarct size by ACC. Analysis by 2-DE revealed the involvement of 19 different cardiac proteins, associated with energy metabolism, oxidative stress and maintenance of cytoskeleton. The expression of those proteins were altered by ISO, but maintained in ACC pretreated rats. Our findings reveal the potential of isolated ACC in the prevention of myocardial damage.

Effect of neoflavonoid latifolin isolated from Dalbergia odorifera on acute myocardial ischemia in rats and its mechanism of Nrf2 signaling pathway

The present study was designed to evaluate the cardioprotective effect of latifolin on pituitrin(Pit) or isoproterenol(ISO)-induced myocardial injury in rats, and further investigate its underlying mechanisms. Rats were administrated sublingually with pituitrin or subcutaneously with isoproterenol to induce acute myocardial ischemia in rats, and lead II electrocardiograph was recorded. In rats with isoproterenol, ELISA assay or colorimetric method was used to detect the content or activity of myocardial injury markers in serum, and the SOD activity and MDA content in myocardium were detected by colorimetric assay; histopathological examination was conducted by HE staining; the frozen section of myocardial tissues was used for DCFH-DA fluorescent staining to detect the content of ROS in myocardium; Western blot was used to detect the protein expression levels of Nrf2, Keap1, HO-1 and NQO1 in myocardium. Results showed that latifolin significantly inhibited ST-segment changes induced by pituitrin or isoproterenol, and increased heart rate. Further mechanism study showed that latifolin reduced cardiac troponin I(cTnI) level, aspartate transaminase(AST) and lactate dehydrogenase(LDH) activities in serum, increased myocardial superoxide dismutase(SOD) activity and reduced myocardial malondialdehyde(MDA) level, and protected myocardium with less necrosis, infiltration of inflammatory cells and fracture of myocardial fibers. Furthermore, latifolin obviously reduced ROS level in myocardium, inhibited the expression of Kelch-like ECH-associated protein-1(Keap1), increased the nuclear translocation of nuclear factor erythroid 2 related factor 2(Nrf2), and promoted the expression of Heme oxygenase-1(HO-1) and NAD(P)H quinone oxidoreductase-1 (NQO1) in myocardial tissues. Our data suggest that latifolin has a potent protective effect against pituitrin or isoproterenol-induced myocardial injury, which may be related to inhibition of oxidative stress by activating Nrf2 signaling pathway.