Commentary on \u201cCardioprotective Effects of Dapagliflozin against Isoproterenol-induced Myocardial Injury in Rats: Biochemical and Histopathological Evidence\u201d

Background:As a leading cause of global morbidity, myocardial infarction (MI) is a primary focus of medical research. The isoproterenol (ISO)-induced model of cardiac injury is a cornerstone of this work, providing a validated experimental system that simulates the human condition. This study investigated the cardioprotective potential of dapagliflozin (DAPA), a sodium-glucose cotransporter-2 (SGLT2) inhibitor, against ISO-induced myocardial injury in adult male rats.Materials and Methods:Thirty-two rats were divided into four groups; Control group, DAPA-only group: DAPA (1 mg/kg/day, orally, 14 days) + saline, ISO-only: Saline (orally, 14 days) + ISO (100 mg/kg/day, days 13–14) and fourth group, DAPA + ISO: pretreated with DAPA 1 mg/kg/day orally) for 14 days, followed by ISO 100 mg/kg, subcutaneously days 13–14. DAPA’s protective effects against ISO-induced MI were evaluated by assessing cardiac damage by measuring serum biomarkers of heart injury while simultaneously evaluating oxidative stress through lipid peroxidation levels and antioxidant activity in cardiac tissue. Histopathological examination revealed structural changes in myocardial tissue, complemented by molecular analysis quantifying the expression of key apoptotic regulators.Results:Biochemical analysis revealed that DAPA significantly reduced ISO-induced elevations in cardiac troponin-I, creatine kinase-MB, lactate dehydrogenase, and oxidative stress markers; malondialdehyde, superoxide dismutase, and reduced glutathione. DAPA also attenuated inflammatory cytokines: tumor necrosis factor-alpha and interleukin-6 (IL-6). Histopathological examination of heart tissues demonstrated that DAPA mitigated ISO-induced myocardial necrosis and inflammatory infiltration, preserving cardiac architecture. Moreover, DAPA downregulated the pro-apoptotic protein (Bax) expression and upregulated the anti-apoptotic protein (Bcl2) levels in the heart.Conclusions:These findings suggest that DAPA exerts multimodal cardio-protection beyond its antidiabetic action, positioning it as a promising adjunct therapy for ischemic heart disease. Further clinical studies are warranted to validate its translational potential.

The present study was undertaken to evaluate the effect of alcoholic extract of Dalbergia sissoo leaf extract (DSE) on isoproterenol (ISP)-induced myocardial injury in rats. Evaluation of three doses (30, 100 and 300 mg/kg of body weight) of DSE was done in ISP-treated rats. ISP was used at 85 mg/kg body weight by subcutaneous route for two subsequent days to induce myocardial injury in rats. Assessment of myocardial injury was done by estimation of different cardiac injury markers like LDH, CK-MB. Serum cholesterol, LDL, HDL, triglycerides in serum, myocardial infarcted area, oxidative stress and histopathology in heart tissue were also assessed in rats. Mean arterial pressure and heart rate were recorded in all the groups. Rats pretreated with DSE (30, 100 and 300 mg/kg of body weight) showed significant (p < 0.05-0.001) improvement in the heart weight/body weight ratio, myocardial infarcted areas, heart rate and mean arterial pressure in ISP-induced myocardial injury. DSE showed significant (p < 0.05-0.001) improvement in serum LDH, CK-MB, cholesterol, LDL and triglyceride levels at all the dose levels. However, DSE pretreatment had no significant effect on serum HDL level. Pretreatment with DSE (30, 100 and 300 mg/kg body weight) showed significant (p < 0.001) reduction in MDA level in comparison with myocardial injured rats. Further, antioxidant potential was also improved in terms of improved activities of reduced glutathione, superoxide dismutase and catalase with the DSE pretreatment. Histopathology also showed significant improvement in heart tissue. The study suggests that DSE showed beneficial effect in ISP-induced myocardial injury in rats.

To clarify the relation between macrophage and myofibroblast involvement in various myocardial diseases, the authors investigated the kinetics of these cells in the healing (scar tissue formation) following isoproterenol-induced myocardial injury in rats. Alpha-smooth muscle actin (alpha-SMA) expressing myofibroblasts were seen at the border of the affected area and appeared in the greatest numbers on days 3-7 post-injection, followed by a gradual decrease by day 35. The peak on day 3 was consistent with the timing of the highest proliferative activity of myofibroblasts. The number of ED1-positive macrophages began to increase as early as day 1, reaching a peak on day 3 within the injured myocardium. The expansion of ED1-positive macrophages preceded an increased number of alpha-SMA-positive myofibroblasts suggesting that myofibroblast proliferation and activation may be mediated by factors released by ED1-positive macrophages in response to myocardial injury. The number of ED2-positive tissue-fixed, resident macrophages gradually, increased from day 3 post-injection, and peaked on day 14, but the number of ED2-positive macrophages was consistently fewer than that of ED1-positive macrophages during the 35 day-observation period after the injection. The labelling index of the ED2-positive cells was maximal on day 14, indicative of local proliferation of resident macrophages. In the healing process after myocardial injury, ED1-positive macrophages increase markedly in the early stages: ED2-positive macrophages appear later.

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.

Myocardial protective effect of Sheng Mai San (SMS) and a lignan-enriched extract of Fructus Schisandrae, in vivo and ex vivo

Cardioprotective effect of embelin on isoproterenol-induced myocardial injury in rats: Possible involvement of mitochondrial dysfunction and apoptosis

ABSTRACTPurpose:To examine the cardioprotective effects of myrrhone against isoproterenol (ISO)-induced myocardial injury in rats.Methods:Myocardial injury was induced in the rats through subcutaneous administration of ISO (85 mg/kg). The body weight, heart weight, electrocardiogram (ECG), cardiac, antioxidant, electrolyte, membrane-bound enzymes, antioxidant, cytokines, and inflammatory parameters were estimated. The mRNA expression of inflammatory parameters was estimated in the cardiac tissue.Results:Myrrhone treatment significantly (p < 0.001) altered ECG parameters, body weight, heart weight, and heart weight/body weight ratio. Myrrhone significantly (p < 0.001) improved the level of 5-hydroxytryptamine (5-HT) and suppressed the level of cardiac parameters like creatine kinase-MB, creatine kinase, lactate dehydrogenase, cardiac troponin I, and cardiac troponin T. It also suppressed the level of hepatic parameters such as aspartate aminotransferase, and alanine transaminase; altered the electrolyte, membrane-bound enzymes, and antioxidant parameters. Myrrhone treatment significantly (p < 0.001) altered the level of cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-10, IL-1β, IL-17, and IL-6; inflammatory parameters like cyclooxygenase-2, prostaglandin, inducible nitric oxide synthetase, nuclear factor kappa-light-chain enhancer of activated B cells; matrix metalloproteinases such as 2, and 9; apoptosis parameters viz., Bcl-2-associated X protein (Bax), B-cell lymphoma 2 protein (Bcl-2), and caspase-3 parameters. Myrrhone treatment significantly (p < 0.001) altered the mRNA expression IL-6, IL-1β, IL-10, TNF-α, Bcl-2, caspase-3, Bax, and caspase-9.Conclusion:Myrrhone exhibited the cardioprotective effect against ISO-induced myocardial injury in rats via alteration of kappa-light-chain enhancer of activated B cells (NF-κB) and Bax/Bcl-2/caspase-3 signaling.

Serum metabolomics analysis reveals that obvious cardioprotective effects of low dose Sini decoction against 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.

The present study was done to evaluate the role of grape seed proanthocyanidins (GSPs) in isoproterenol (ISO)-induced myocardial injury in rats. Male albino Wistar rats were pretreated with GSP (50, 100, and 150 mg/kg), 6 days a week, for 5 weeks. Induction of rats with ISO (85 mg/kg body weight, intraperitoneally) for 2 days resulted in a significant elevation of thiobarbituric acid-reactive substances in serum, mitochondrial cholesterol, triglycerides, and free fatty acids. A significant decrease was observed in serum reduced glutathione; ascorbic acid; alpha-tocopherol; ceruloplasmin; and mitochondrial cytochromes (b, c, c1, and aa3), phospholipids, and adenosine triphosphate. Pretreatment with GSP (100 and 150 mg/kg) positively altered the levels of all the parameters studied and restored normal mitochondrial function when compared with ISO-induced rats. The effect at a dose of 50 mg/kg was not promising when compared with the other 2 doses (100 and 150 mg/kg). These results confirm the efficacy of GSP in alleviating ISO-induced myocardial injury.

This study was designed to investigate the effect of oral curcumin pretreatment (200 mg/kg) on isoproterenol-induced myocardial injury in rats. Isoproterenol (85 mg/kg, s.c., in two divided doses at 24 h intervals) administration induced a statistically significant increase (P < 0.01) in serum lactate dehydrogenase, creatine kinase, aspartate transaminase, and alanine transaminase activities and significant increase (P < 0.01) in myocardial lipid peroxides levels as compared to vehicle control rats. Furthermore, significant depletion (P < 0.01) of myocardial endogenous antioxidants viz. superoxide dismutase, catalase, and tissue glutathione levels were also found in the pathogenic control group, that is, isoproterenol only treated animals. Curcumin (200 mg/kg) pretreatment for 20 days in isoproterenol treated rats significantly lowered (P < 0.01) the serum lactate dehydrogenase, creatine kinase, aspartate transaminase, alanine transaminase, and myocardial lipid peroxides levels and increased the levels of myocardial endogenous antioxidants (superoxide dismutase, catalase, and tissue glutathione) as compared to pathogenic control rats. Furthermore, histological examination of rat's heart section confirmed myocardial injury with isoproterenol administration and near normal pattern with curcumin pretreatment. The results of our study provide clear evidence that the curcumin pretreatment enhances the antioxidant defense against isoproterenol-induced oxidative myocardial injury in rats and exhibit cardioprotective property.

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.

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

Kuanxiong aerosol inhibits apoptosis and attenuates isoproterenol-induced myocardial injury through the mitogen-activated protein kinase pathway

MicroRNAs (miRNAs) are endogenous small RNAs of 21-25 nucleotides that can pair with sites in 3' untranslated regions in mRNAs of protein-coding genes to downregulate their expression. Recently, circulating miRNAs have been reported as promising biomarkers for various pathologic conditions. We assessed the hypothesis that miRNAs may leak into the circulating blood from injured cells and thereby serve as biomarkers for identifying the injured cell type. We used isoproterenol-induced myocardial injury in rats as a model and miRNA array analyses to identify candidate miRNAs specifically produced in the ventricles of the heart. Individual miRNA concentrations were measured by real-time reverse-transcription PCR. Plasma cardiac troponin I (cTnI) concentrations were measured with an ELISA. Array analyses revealed miR-208 to be produced exclusively in the heart, and we selected this miRNA as a possible biomarker of myocardial injury. Plasma concentrations of miR-208 increased significantly (P < 0.0001) after isoproterenol-induced myocardial injury and showed a similar time course to the concentration of cTnI, a classic biomarker of myocardial injury. The plasma concentration of miR-208 may be a useful indicator of myocardial injury. Our results suggest that profiling of circulating miRNAs may help identify promising biomarkers of various pathologic conditions.