Adriamycin-induced Cardiomyopathy In Rats Research Articles

Impact of ethyl pyruvate on Adriamycin-induced cardiomyopathy in rats.

Ethyl pyruvate (EP), a derivative of pyruvic acid, is known to have protective effects against ischemic cardiomyopathy and other disorders. However, little is known about its role in Adriamycin (ADR)-induced cardiomyopathy. The present study was designed to investigate the impact of EP on ADR-induced cardiomyopathy in an animal model. Sixty male Sprague-Dawley (SD) rats were divided into four groups: Normal control, EP, ADR and ADR + EP groups (n=15/group). Rats in the ADR and ADR + EP groups were treated with ADR (2.5 mg/kg/week intraperitoneally) for 6 weeks. From the eighth week, rats in the EP and ADR + EP groups received EP via gastric lavage at a dose of 50 mg/kg/day for 30 days. After completing the EP treatment, cardiac function was assessed by echocardiography and then rats were sacrificed. Hearts were harvested for subsequent analysis. Compared with rats in the normal control and EP groups (without ADR treatment), rats in the ADR and ADR + EP groups showed significant impairments in terms of cardiac function, apoptosis, severe oxidative stress and fibrosis in the heart. However, these impairments were alleviated by EP treatment in the ADR + EP group. Upon EP treatment, cardiac function was significantly improved. The levels of oxidative stress, fibrosis and apoptosis in the myocardial tissues were also significantly reduced. These findings indicated that EP treatment attenuated, at least partially, ADR-induced cardiomyopathy in rats.

Antioxidant defense of glutamine on myocardial antioxidant status in adriamycin-induced cardiomyopathy in rats

Oxidative stress is one of the major factors involved in the pathogenesis of adriamycin-induced cardiac dysfunction. The present study examined the antioxidant defense of glutamine on myocardial antioxidant status in adriamycin-induced cardiomyopathy in rats with respect to changes in the levels of lipid peroxidation and reduced glutathione, and the activities of antiperoxidative enzymes [superoxide dismutase (SOD) and catalase (CAT)] and glutathione dependent antioxidant enzymes [glutathione peroxidase (GPx) and glutathione-S-transferase (GST)] in the heart tissue. Intraperitoneal injection of adriamycin caused a significant (P<0.001) rise in the level of lipid peroxidation in the heart tissue with a concomitant (P<0.001) decline in the level of reduced glutathione and the activities of the antioxidant enzymes. Oral administration of glutamine significantly (P<0.001) ameliorated these adriamycin induced adverse effects and maintained the level of the evaluated parameters nearly at normal. The results of the present investigation demonstrated that the protective effects of glutamine against the toxicity of the prooxidant antitumor drug, adriamycin, might be attributed at least partially to its antioxidant properties.

Protective effect of Picrorhiza kurroa on antioxidant defense status in adriamycin-induced cardiomyopathy in rats

Adriamycin, an anthracycline antibiotic, which is used in the treatment of various tumors, is known to cause severe cardiomyopathy. The present study examined the protective effects of Picrorhiza kurroa, an ayurvedic medicinal plant, on myocardial antioxidant defense system in adriamycin-induced cardiomyopathy in rats. Intraperitoneal administration of adriamycin (1.5 mg/kg body weight/ day, i.p. for 15 days) caused significant rise in the levels of diagnostic marker enzymes [alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine phoshokinase (CPK)] in plasma and lipid peroxidation in the heart tissue of experimental rats. Concomitant decline in the level of reduced glutathione (GSH) and the activities of glutathione-dependent antioxidant enzymes (GPx and GST) and antiperoxidative enzymes (SOD and CAT) in the myocardial tissue were also observed. Oral administration of P. kurroaextract (50 mg/kg body weight/day, for a period of 15 days) significantly prevented all these adriamycin-induced adverse effects and maintained the rats at normal status. The protective effect of P. kurroa might be ascribable to its membrane-stabilizing property and/or antioxidant nature. Key words: Picrorhiza kurroa, adriamycin, cardiomyopathy, diagnostic marker enzymes, lipid peroxidation, antioxidant status.

Granulocyte Colony-Stimulating Factor Reduces Cardiomyocyte Apoptosis and Improves Cardiac Function in Adriamycin-Induced Cardiomyopathy in Rats

Cardiomyocyte apoptosis reportedly participates in the occurrence and progression of dilated cardiomyopathy (DCM). Recent studies have shown that granulocyte colony-stimulating factor (G-CSF) enhances bone marrow cells migration to the damaged heart in the DCM model and improves the ultrastructure of the cardiomyocyte in adriamycin (ADR) induced DCM. However, its influence on cardiac pump function and cardiomyocyte apoptosis has not been studied. Wistar Rats were randomly grouped into control, ADR, ADR+PBS, ADR+G-CSF group (n = 10). ADR (2.5 mg/kg, 6 times for 2 weeks) was administered intraperitoneally in all rats except the control group. After 2 weeks, the rats in ADR+G-CSF group were injected with G-CSF (50 microg/kg/day for 8 days) subcutaneously. Cardiac function was evaluated by echocardiogram and cardiac catheterization after 4 weeks. Cardiomyocytes apoptosis and apoptosis-related protein Fas were detected by in situ terminal deoxynucleotidyl transferase assay (TUNEL method) and Western blot, respectively. The ADR and ADR+PBS groups showed significant deteriorations of left ventricular functions and high cardiomyocyte apoptosis index, as well as high Fas expressions. Meanwhile, the ADR+G-CSF group showed significant improvement in LV function, inhibition of cardiomyocyte apoptosis compared with the ADR and ADR+Phosphate-Buffered Saline PBS group. The Fas protein expression was remarkably attenuated as well. Our results suggest that administration of G-CSF inhibited cardiomyocyte apoptosis and Fas protein expression and contributes to improving cardiac pump function in vivo in ADR induced DCM rat model.

Sheng-Mai-San Reduces Adriamycin-Induced Cardiomyopathy in Rats

The traditional Chinese medicine prescription "sheng-mai-san (SMS)" has been used for treating patients with coronary heart disease for a long time and was found to have antioxidative effects. Here, we applied adriamycin (doxorubicin, ADR), a highly effective anticancer agent, as an inducer to establish the animal model of dose-related cardiomyopathy due to inhibition of nucleic acid as well as protein synthesis, formation of free radicals, and lipid peroxidation. The objective of this study was to investigate the protective effects of SMS on adriamycin-induced cardiomyopathy. Wistar rats were divided into four groups: CONT (control), ADR, SMS, and ADR + SMS. ADR (cumulative dose, 15 mg/kg) was administered to rats in six equal intraperitoneal injections over a period of 2 weeks and SMS was administered via a feeding tube throughout the mouth once a day for 30 days (cumulative dose, 150 g/kg). At the end of the 5-week post-treatment period, the hearts of the rats were surgically removed for the study of synthesis rates of DNA, RNA and proteins. Besides myocardial antioxidants, lipid peroxidation and morphological ultrastructure were also evaluated. Three weeks after the treatment, cardiomyopathy and congestive heart failure were characterized according to assessment in ascites, congested liver, depressed cardiac function and myocardial cell damage. The results demonstrated that nucleic acid as well as protein synthesis was inhibited, while lipid peroxidation was increased. Myocardial glutathione peroxidase (GSHPx) activity was decreased and electron microscopic examination revealed myocardial lesion indicative of ADR-induced cardiomyopathy. In contrast, administration of SMS before and concurrent with ADR significantly attenuated the myocardial effects. It also lowered mortality as well as the amount of ascites. In addition, indexes in myocardial GSHPx, macromolecular biosynthesis and superoxide dismutase activities were increasing, with a concomitant decrease in lipid peroxidation and preserved myocardial ultrastructure. These results indicated that SMS may be partially protective against ADR-induced cardiomyopathy.

Selective sensory denervation by capsaicin aggravates adriamycin-induced cardiomyopathy in rats

Capsaicin-sensitive sensory nerves that contain calcitonin gene-related peptide (CGRP) contribute significantly to cardioprotective mechanisms. In this study, the possible role of capsaicin-sensitive afferent nerves in the development of congestive heart failure was examined in an established model of adriamycin-induced experimental cardiomyopathy in rats. Systemic treatment with capsaicin was utilized to deplete sensory neuropeptides from cardiac afferent nerves. Echocardiography was applied to assess the cardiac function in adriamycin-treated rats pretreated with capsaicin or its vehicle. In control rats, adriamycin treatment produced a reduction in the fractional shortening of the left ventricle and an increase in the ratio of the left atrial diameter and the aortic diameter, indicative of a decreased myocardial contractility and heart failure only at 3-4 weeks post-treatment. In contrast, in capsaicin-pretreated rats, a deterioration of the cardiac function was already evident 1 week after the cessation of adriamycin administration, while the clinical signs associated with cardiomyopathy were more severe and displayed a significantly more rapid progression. Immunohistochemistry revealed a complete depletion of calcitonin gene-related peptide from cardiac sensory nerves after systemic capsaicin treatment. This study has demonstrated that elimination of capsaicin-sensitive afferent nerves promotes the development and progression of adriamycin-induced myocardial dysfunction. The results suggest that interfering with capsaicin/vanilloid receptor function and/or perturbation of the myocardial CGRP metabolism may open up new perspectives concerning prevention and/or alleviation of the pathological changes that follow adriamycin treatment.

Troponin-T and brain natriuretic peptide as predictors for adriamycin-induced cardiomyopathy in rats.

Clinical methods for the early detection of doxorubicine (adriamycin; ADR) -induced cardiotoxicity have not been established. This study prospectively investigated whether atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and cardiac troponin T (TnT) are predictors for ADR-induced cardiotoxicity, and examined the correlations between the serum concentrations of these biomarkers and the functional alternations associated with ADR-induced myocardial damage. Male Wistar rats were injected weekly with 2 mg/kg of ADR via the tail vein for 8 weeks to induce cardiotoxicity. Echocardiograms of each ether anesthetized rat were taken at 6, 8, 10 and 12 weeks after the first administration of ADR, and blood samples collected from the tail vein were used to quantify plasma ANP and BNP, and serum TnT after echocardiography. Plasma BNP and serum TnT significantly increased from 6 to 12 weeks (81.5 to 173.3 pg/ml (p<0.001), <0.01 to 1.09 ng/ml (p<0.05), respectively) with deterioration of left ventricular % fractional shortening (%FS) (58.6% to 36.8%). The %FS significantly correlated with TnT (r=-0.51, p<0.001) and BNP (r=-0.75, p<0.0001); however, the increase of TnT was antecedent to the increase of BNP and the deterioration of %FS. Plasma BNP and serum TnT concentrations, especially TnT, measured by this highly sensitive method are useful predictors for ADR-induced cardiomyopathy.

Maintenance of Myocardial Levels of Vitamin A in Heart Failure due to Adriamycin

I. Danelisen, V. Palace, H. Lou and P. K. Singal. Maintenance of Myocardial Levels of Vitamin A in Heart Failure due to Adriamycin. Journal of Molecular and Cellular Cardiology (2002) 34, 789–795. The therapeutic use of adriamycin (doxorubicin), a potent antitumor antibiotic, is limited by the development of dose-dependent cardiomyopathy. Increased oxidative stress due to adriamycin is considered to play a role in the pathogenesis of this toxic effect. In this study, we examined the levels and redistribution of vitamin A (a potent non-enzymatic antioxidant) in adriamycin-induced cardiomyopathy in rats. Three weeks after the adriamycin (ADR) treatment, animals were hemodynamically assessed and different tissues were analyzed for total retinol (vitamin A), 3H-radio-labeled retinol, retinol palmitate and vitamin E. At 3 weeks, animals in the ADR group were hemodynamically and clinically confirmed to be in heart failure. In the ADR group, total retinol levels in heart and plasma were unchanged. However, levels of the 3H radio-labeled fraction of retinol were significantly increased in both organs suggesting increased turnover. In the liver, the levels of total retinol and retinol palmitate were significantly decreased, while the radio-labeled fraction of retinol was significantly increased suggesting mobilization of retinol from this organ. Alpha tocopherol (vitamin E) levels were found unchanged in hearts of the ADR animals, while its levels in the plasma and liver were significantly increased. Increased radio-labeled fraction, without any change in the total retinol in the heart, suggested that vitamin A is utilized more by the heart under increased oxidative stress due to adriamycin. Its levels in the plasma and the heart may have been maintained at the expense of the loss from the liver.

Fas-mediated apoptosis in adriamycin-induced cardiomyopathy in rats: In vivo study.

The precise molecular mechanism of Adriamycin-induced cardiomyopathy (ADR-CM) is still unknown. We address the demonstration of apoptotic myocardial cell death and the apoptosis-inducing molecules in ADR-CM induced in rats. Until 8 weeks after the first administration of ADR, there was no increase in the number of labeled cells by terminal deoxynucleotidyl transferase assay (TUNEL method). Apoptotic indices increased significantly at weeks 9 and 10 in hearts of the ADR-treated group but not in those of the control group (0.42+/-0.12% versus 0.10+/-0.02% and 0.86+/-0.11% versus 0.09+/-0.04% at weeks 9 and 10, respectively). DNA ladder formation was also observed in the myocardial tissues during the late stages of the ADR-CM of rats. There was no significant difference in expression of p53 gene between the ADR group and the control group at either the message or the protein level. An overexpression of Fas antigen was shown in myocardial cells of ADR-treated hearts at weeks 9 and 10 by both Western blotting and immunofluorescent staining. Furthermore, we confirmed that neutralization of anti-Fas ligand antibody inhibited ADR-induced apoptosis. Apoptotic cell death was observed in the hearts of ADR-CM rats, and the number of apoptotic myocardial cells increased with the deterioration of morphological findings and cardiac function, indicating that apoptosis may be an important mechanism of loss of myocardial cells and cardiac dysfunction in ADR-CM. Apoptosis in ADR-CM rats is not p53-dependent but rather is executed through a Fas-mediated pathway.

Effects of probucol on changes of antioxidant enzymes in adriamycin-induced cardiomyopathy in rats.

The clinical usefulness of doxorubicin (adriamycin, ADR) is restricted by the risk of developing congestive heart failure. Probucol has been reported to completely prevent ADR cardiomyopathy without interfering with its antitumor effects. The current study investigated the effects of ADR and probucol on antioxidant enzyme gene expression during adriamycin-induced cardiomyopathy in a rat model. The mRNA abundance by Northern and immunoreactive protein levels by Western blotting of myocardial antioxidant enzymes, glutathione peroxidase (GSHPx), manganese superoxide dismutase (MnSOD) and catalase (CAT) were examined in relation to the enzyme activities in hemodynamically assessed control and treated animals. At 3 weeks post-treatment duration, ADR caused heart failure which was prevented by probucol. MnSOD mRNA abundance as well as protein levels were depressed by ADR treatment by 45% and 20%, respectively, and this change was prevented by probucol. However, the mRNA and protein levels of GSHPx and CAT were not significantly changed by ADR or probucol. ADR had no effect on SOD activity but this enzyme activity was increased by probucol and probucol plus ADR. GSHPx enzyme activity was decreased and oxidative stress as indicated by TBARS was increased by ADR and these changes were also modulated by probucol. An increase in oxidative stress, GSHPx inactivation and MnSOD downregulation during ADR cardiomyopathy were prevented by probucol treatment.

Transthoracic Echocardiographic Assessment of Adriamycin-induced Cardiomyopathy in Rats with a 15 MHz Transducer

Transthoracic Echocardiographic Assessment of Adriamycin-induced Cardiomyopathy in Rats with a 15 MHz Transducer

Probucol promotes endogenous antioxidants and provides protection against adriamycin-induced cardiomyopathy in rats.

The potential usefulness of adriamycin (ADR) is restricted because of its cardiotoxic side effects. Since free radicals and lipid peroxidation are suggested to be involved in ADR cardiomyopathy, we examined the beneficial effects of probucol, a lipid-lowering drug with strong antioxidant properties. ADR was administered to rats in six equal intraperitoneal injections over a period of 2 weeks (cumulative dose of 15 mg/kg). After a 3-week posttreatment period, cardiomyopathy and congestive heart failure were characterized by ascites, congested liver, depressed cardiac function, elevated left ventricular end-diastolic pressure, and myocardial cell damage. Myocardial glutathione peroxidase (GSHPx) activity was decreased, and lipid peroxidation was increased. Probucol (cumulative dose, 60 mg/kg IP) was administered in six equal injections over a 2-week period on days alternating with ADR treatment. Probucol significantly attenuated the myocardial effects of ADR, improved left ventricular function, and lowered mortality as well as the amount of ascites. Treatment with probucol was also accompanied by an increase in myocardial GSHPx and superoxide dismutase activities, with a concomitant decrease in lipid peroxidation. These data provide evidence that ADR cardiomyopathy is associated with an antioxidant deficit. Improved cardiac function resulting from treatment with probucol may be related to the maintenance of the antioxidant status of the heart. The study suggests potential usefulness of antioxidant (probucol) therapy in ADR cardiomyopathy.

The influence of inosine on adriamycin-induced cardiomyopathy in rats

The effect of inosine on adriamycin-induced cardiomyopathy was studied. Total adriamycin (ADR) dose of 25 mg/kg i.p. injected in 15 equal partial doses 3 times a week for five following weeks evoked fully developed cardiomyopathy in rats. Inosine 200 mg/kg i.p. injected 5 times a week parallel to ADR diminished ADR cardiotoxicity evaluated by electrocardiographic recordings and histopathological examination. Moreover lower cytostatic toxicity was observed as judged by less-expressed leucopenia and lower SGOT activities in inosine treated animals

Carnitine protection against adriamycin-induced cardiomyopathy in rats

The effects of chronic adriamycin toxicity on myocardial carnitine content and contractile function were studied in rats, along with potential protective effect of L-carnitine administration. Cardiomyopathy was induced over a 6- to 7-week period by weekly intravenous injections of adriamycin, 2 mg/kg. In vivo myocardial tissue levels of carnitine were not significantly changed by adriamycin, but plasma levels were elevated. Cardiac output was depressed in isolated perfused hearts from adriamycin-treated rats perfused with 11 mM glucose. In a second experiment, 4-week-old male rats were divided into four groups: saline-treated control, L-carnitine-treated control, saline-treated adriamycin, and L-carnitine-treated adriamycin. L-Carnitine was given intraperitoneally each day at a dose of 500 mg/kg. Myocardial histology and ultrastructure were analyzed. Cardiac performance was determined in hearts perfused with 1.2 mM palmitate and 5.5 mM glucose. Hearts from saline-treated adriamycin rats showed histopathological changes and a significantly diminished cardiac output at various preloads when compared to saline-treated controls. Daily intraperitoneal L-carnitine reduced histopathological alterations and improved cardiac performance.

Effects of ICRF 159 on adriamycin-induced cardiomyopathy in rats

The effect of ICRF 159 on adriamycin (ADR) cardiotoxicity and on total myocardial calcium content was examined in rats. ICRF 159 did not increase the survival time of ADR-treated animals; however the histological findings showed a significant prevention of ADR-induced cardiomyopathy (CMP) by ICRF. The total myocardial calcium content of animals treated with ADR was significantly higher, while no significant difference was seen in animals pretreated with ICRF 159 as compared with controls. As these findings suggested a role of calcium in ADR CMP and in the pharmacological action of ICRF in this disease, we also tested a closely related chelating agent, EDTA. This molecule decreased myocardial calcium levels in ADR-treated animals almost to normal values; however the histological cardiac alterations were not prevented.