The protective effect of glutathione administration on adriamycin-induced acute cardiac toxicity in rats

The In Vitro, In Vivo, and PBPK Evaluation of a Novel Lung-Targeted Cardiac-Safe Hydroxychloroquine Inhalation Aerogel

Hydroxychloroquine (HCQ) was repurposed for COVID-19 treatment. Subtherapeutic HCQ lung levels and cardiac toxicity of oral HCQ were overcome by intratracheal (IT) administration of lower HCQ doses. The crosslinker-free supercritical fluid technology (SFT) produces aerogels and impregnates them with drugs in their amorphous form with efficient controlled release. Mechanistic physiologically based pharmacokinetic (PBPK) modeling can predict the lung's epithelial lining fluid (ELF) drug levels. This study aimed to develop a novel HCQ SFT formulation for IT administration to achieve maximal ELF levels and minimal cardiac toxicity. HCQ SFT formulation was prepared and evaluated for physicochemical, in vitro release, pharmacokinetics, and cardiac toxicity. Finally, the rat HCQ ELF concentrations were predicted using PBPK modeling. HCQ was amorphous after loading into the chitosan-alginate nanoporous microparticles (22.7±7.6 μm). The formulation showed a zero-order release, with only 40% released over 30 min compared to 94% for raw HCQ. The formulation had a tapped density of 0.28 g/cm3 and a loading efficiency of 35.3±1.3%. The IT administration of SFT HCQ at 1 mg/kg resulted in 23.7-fold higher bioavailability, fourfold longer MRT, and eightfold faster absorption but lower CK-MB and LDH levels than oral raw HCQ at 4 mg/kg. The PBPK model predicted 6 h of therapeutic ELF levels for IT SFT HCQ and a 100-fold higher ELF-to-heart concentration ratio than oral HCQ. Our findings support the feasibility of lung-targeted and more effective SFT HCQ IT administration for COVID-19 compared to oral HCQ with less cardiac toxicity. Graphical abstract.

The Protective Role of Glutathione against Doxorubicin-Induced Cardiotoxicity in Human Cardiac Progenitor Cells

This study investigated the protective effect of glutathione (GSH), an antioxidant drug, against doxorubicin (DOX)-induced cardiotoxicity. Human cardiac progenitor cells (hCPCs) treated with DOX (250 to 500 nM) showed increased viability and reduced ROS generation and apoptosis with GSH treatment (0.1 to 1 mM) for 24 h. In contrast to the 500 nM DOX group, pERK levels were restored in the group co-treated with GSH and suppression of ERK signaling improved hCPCs' survival. Similarly to the previous results, the reduced potency of hCPCs in the 100 nM DOX group, which did not affect cell viability, was ameliorated by co-treatment with GSH (0.1 to 1 mM). Furthermore, GSH was protected against DOX-induced cardiotoxicity in the in vivo model (DOX 20 mg/kg, GSH 100 mg/kg). These results suggest that GSH is a potential therapeutic strategy for DOX-induced cardiotoxicity, which performs its function via ROS reduction and pERK signal regulation.

The Role of Nutrition in Primary and Secondary Prevention of Cardiovascular Damage in Childhood Cancer Survivors

Innovative therapeutic strategies in childhood cancer led to a significant reduction in cancer-related mortality. Cancer survivors are a growing fragile population, at risk of long-term side effects of cancer treatments, thus requiring customized clinical attention. Antineoplastic drugs have a wide toxicity profile that can limit their clinical usage and spoil patients' life, even years after the end of treatment. The cardiovascular system is a well-known target of antineoplastic treatments, including anthracyclines, chest radiotherapy and new molecules, such as tyrosine kinase inhibitors. We investigated nutritional changes in children with cancer from the diagnosis to the end of treatment and dietary habits in cancer survivors. At diagnosis, children with cancer may present variable degrees of malnutrition, potentially affecting drug tolerability and prognosis. During cancer treatment, the usage of corticosteroids can lead to rapid weight gain, exposing children to overweight and obesity. Moreover, dietary habits and lifestyle often dramatically change in cancer survivors, who acquire sedentary behavior and weak adherence to dietary guidelines. Furthermore, we speculated on the role of nutrition in the primary prevention of cardiac damage, investigating the potential cardioprotective role of diet-derived compounds with antioxidative properties. Finally, we summarized practical advice to improve the dietary habits of cancer survivors and their families.

Cardioprotective Effect of Rheum turkestanicum Against Doxorubicin-Induced Toxicity in Rats

Background: Doxorubicin as an anti-cancer drug causes cardiotoxicity, limiting its tolerability and use. The mechanism of toxicity is due to free radical production and cardiomyocytes injury. This research evaluated Rheum turkestanicum (R.turkestanicum) extract against doxorubicin cardiotoxicity due to its considerable in vitro antioxidant activity. Methods: Male Wistar rats received 2.5 mg/kg doxorubicin intraperitoneally every other day for 2 weeks to create an accumulative dose. R. turkestanicum was administrated at a dose of 100 and 300 mg/kg intraperitoneally from the second week for 7 days. On the 15th day, the animals were anesthetized and blood was collected from cardiac tissue for evaluation of alanine aminotransferase (ALT), cardiac muscle creatinine kinase (CK-MB), troponin T (cTn-T), lactate dehydrogenase (LDH), and B-type natriuretic peptide brain natriuretic peptide. A cardiac homogenate was also collected to determine superoxide dismutase (SOD), catalase Catalase Activity, malondialdehyde (MDA), and thiols. Histopathology was also performed. Results: Doxorubicin increased all cardiac enzymes and malondialdehyde, correlating with a reduction in SOD, catalase, and thiols. Histopathology revealed extracellular edema, moderate congestion, and hemorrhage of foci. In contrast, administration of R. turkestanicum ameliorated these doxorubicin-induced pathophysiological changes. Conclusion: This study revealed that the extract ameliorated doxorubicin-induced cardiac toxicity via modulation of oxidative stress-related pathways. Liquid chromatography-mass spectrometry analysis of R. turkestanicum indicated several components with potent pharmacological properties.

Genotoxicity, nitric oxide level modulation and cardio-protective potential of Kalanchoe Integra Var. Crenata (Andr.) Cuf Leaves in murine models

ETHNOPHARMACOLOGICAL RELEVANCE

Advancement in cancer therapy has improved survival among patients. However, use of anticancer drugs like anthracyclines (e.g., doxorubicin) is not without adverse effects. Notable among adverse effects of doxorubicin (DOX) is cardiotoxicity, which ranges from mild transient blood pressure changes to potentially serious heart failure. Anecdotal reports suggest that Kalanchoe integra (KI) may have cardio-protective potential.

AIMS OF THE STUDY

This study sought to determine the cardio-protective potential of KI against doxorubicin-induced cardiotoxicity and also examined any possible genotoxic potential of KI in selected organs. Additionally, the nitric oxide modulatory potential of KI was assessed.

MATERIALS AND METHODS

The leaves of KI were collected, air-dried, pulverised and extracted using 70% ethanol. High-performance liquid chromatography (HPLC) fingerprinting was done for KI. Also, the single-cell gel electrophoresis assay (Comet assay) was employed to ascertain the genotoxic potential of KI. In assessment of cardio-protective potential of KI against doxorubicin-induced cardiotoxicity, a total of 42 female Sprague-Dawley rats were put into 7 groups (n = 6). Group I: vehicle control, received normal saline (1 mL/kg p.o) for 30 days. Group II: toxic control, received DOX (20 mg/kg i.p.) once on the 29th day. Group III: KI control, received KI (300 mg/kg p.o) for 30 days. Group IV: vitamin E control, received vitamin E (100 mg/kg p.o) for 30 days. Group V: KI treated-1, received KI (300 mg/kg p.o) for 30 days and DOX (20 mg/kg i.p) on the 29th day. Group VI: KI treated-2, received KI (600 mg/kg p.o) for 30 days and DOX (20 mg/kg i.p) on the 29th day. Group VII: vitamin E treated, received vitamin E (100 mg/kg p.o) for 30 days and DOX (20 mg/kg i.p) on the 29th day. Thirty-six (36) hours after last administration, rats were sacrificed. Blood samples were taken via cardiac puncture to determine levels of aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), lactate dehydrogenase (LDH), enzymatic antioxidants such as glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). Nitric oxide level was also determined. Hearts of rats in each group were excised and taken through histopathological examination.

RESULTS

In the HPLC fingerprint analysis, 13 peaks were identified, and peak with retention time of 24.0 min had the highest peak area (3.223 x104 mAU). Comet assay showed that the KI extract was non-genotoxic. Pretreatment with KI protected rats against doxorubicin-induced cardiotoxicity as evidenced by the low levels of AST, ALT, ALP, CK and LDH compared with the controls (p < 0.05). SOD, CAT and GPX levels were also high for rats administered KI extracts, further showing that KI protected rats against doxorubicin-induced cardiotoxicity. KI also inhibited nitric oxide levels at 300 mg/kg and 600 mg/kg effective doses. Histological examination revealed that rats pretreated with KI showed no signs of abnormal myocardial fibres (shape, size and configuration).

CONCLUSION

Ethanolic (70%) leaf extract of KI showed no genotoxic potential and possessed cardioprotective effects against doxorubicin-induced cardiotoxicity in Sprague-Dawley rats. KI also inhibited nitric oxide production, thus, a potential nitric oxide scavenger.

Therapeutic Targets for DOX-Induced Cardiomyopathy: Role of Apoptosis vs. Ferroptosis

Doxorubicin (DOX) is the most widely used anthracycline anticancer agent; however, its cardiotoxicity limits its clinical efficacy. Numerous studies have elucidated the mechanisms underlying DOX-induced cardiotoxicity, wherein apoptosis has been reported as the most common final step leading to cardiomyocyte death. However, in the past two years, the involvement of ferroptosis, a novel programmed cell death, has been proposed. The purpose of this review is to summarize the historical background that led to each form of cell death, focusing on DOX-induced cardiotoxicity and the molecular mechanisms that trigger each form of cell death. Furthermore, based on this understanding, possible therapeutic strategies to prevent DOX cardiotoxicity are outlined. DNA damage, oxidative stress, intracellular signaling, transcription factors, epigenetic regulators, autophagy, and metabolic inflammation are important factors in the molecular mechanisms of DOX-induced cardiomyocyte apoptosis. Conversely, the accumulation of lipid peroxides, iron ion accumulation, and decreased expression of glutathione and glutathione peroxidase 4 are important in ferroptosis. In both cascades, the mitochondria are an important site of DOX cardiotoxicity. The last part of this review focuses on the significance of the disruption of mitochondrial homeostasis in DOX cardiotoxicity.

Antioxidant Potential and Inhibition of Mitochondrial Permeability Transition Pore by Myricetin Reduces Aluminium Phosphide-Induced Cytotoxicity and Mitochondrial Impairments

Oxidative stress and mitochondrial dysfunction are involved in the mechanisms of cardiac toxicity induced by aluminum phosphide (AlP). AlP-induced cardiotoxicity leads to cardiomyocyte death, cardiomyopathy, cardiac dysfunction, and eventually severe heart failure and death. Importantly, protecting cardiomyocytes from death resulting from AlP is vital for improving survival. It has been reported that flavonoids such as myricetin (Myr) act as modifiers of mitochondrial function and prevent mitochondrial damage resulting from many insults and subsequent cell dysfunction. In this study, the ameliorative effect of Myr, as an important antioxidant and mitochondrial protective agent, was investigated in cardiomyocytes and mitochondria isolated from rat heart against AlP-induced toxicity, oxidative stress, and mitochondrial dysfunction. Treatment of AlP (20 μg/ml) significantly increased cytotoxicity; reduced glutathione (GSH) depletion, cellular reactive oxygen species (ROS) formation, malondialdehyde (MDA) level, ATP depletion, caspase-3 activation, mitochondrial membrane potential (ΔΨm) collapse, and lysosomal dysfunction; and decreased the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in intact cardiomyocytes. Also, treatment of AlP (20 μg/ml) significantly increased mitochondrial dysfunction and swelling in isolated mitochondria. Myr (80 µM) appeared to ameliorate AlP-induced cytotoxicity in isolated cardiomyocytes; significantly lessened the AlP-stimulated intracellular ROS and MDA production and depletion of GSH; and increased the activities of SOD, CAT, and GSH-Px. Furthermore, Myr (40 and 80 µM) lowered AlP-induced lysosomal/mitochondrial dysfunction, ATP depletion, and caspase-3 activation. In the light of these findings, we concluded that Myr through antioxidant potential and inhibition of mitochondrial permeability transition (MPT) pore exerted an ameliorative role in AlP-induced toxicity in isolated cardiomyocytes and mitochondria, and it would be valuable to examine its in vivo effects.

Design, synthesis and mechanistic study of novel diarylpyrazole derivatives as anti-inflammatory agents with reduced cardiovascular side effects

Novel diarylpyrazole (5a-d, 6a-e, 12, 13, 14, 15a-c and 11a-g) derivatives were designed, synthesized and evaluated for their dual COX-2/sEH inhibitory activities via recombinant enzyme assays to explore their anti-inflammatory activities and cardiovascular safety profiles. Comprehensively, the structures of the synthesized compounds were established via spectral and elemental analyses, followed by the assessment of both their in vitro COX inhibitory and in vivo anti-inflammatory activities. The most active compounds as COX inhibitors were further evaluated for their in vitro 5-LOX and sEH inhibitory activities, alongside with their in vivo analgesic and ulcerogenic effects. Compounds 6d and 11f showed excellent inhibitory activities against both COX-2 and sEH (COX-2 IC₅₀ = 0.043 and 0.048 µM; sEH IC₅₀ = 83.58 and 83.52 μM, respectively). Moreover, the compounds demonstrated promising results as anti-inflammatory and analgesic agents with considerable ED₅₀ values and gastric safety profiles. Remarkably, the most active COX inhibitors 6d and 11f possessed improved cardiovascular safety profiles, if compared to celecoxib, as shown by the laboratory evaluation of both essential cardiac biochemical parameters (troponin-1, prostacyclin, tumor necrosis factor-α, lactate dehydrogenase, reduced glutathione and creatine kinase-M) and histopathological studies. On the other hand, docking simulations confirmed that the newly synthesized compounds displayed sufficient structural features required for binding to the target COX-2 and sEH enzymes. Also, in silico ADME studies prediction and drug-like properties of the compounds revealed favorable oral bioavailability results. Collectively, the present work could be featured as a promising future approach towards novel selective COX-2 inhibitors with declined cardiovascular risks.

Protecting the heart in cancer therapy

Recent advances in cancer prevention and management have led to an exponential increase of cancer survivors worldwide. Regrettably, cardiovascular disease has risen in the aftermath as one of the most devastating consequences of cancer therapies. In this work, we define cancer therapeutics-induced cardiotoxicity as the direct or indirect cardiovascular injury or injurious effect caused by cancer therapies. We describe four progressive stages of this condition and four corresponding levels of prevention, each having a specific goal, focus, and means of action. We subsequently unfold this didactic framework, surveying mechanisms of cardiotoxicity, risk factors, cardioprotectants, biomarkers, and diagnostic imaging modalities. Finally, we outline the most current evidence-based recommendations in this area according to multidisciplinary expert consensus guidelines.

Definition of hidden drug cardiotoxicity: paradigm change in cardiac safety testing and its clinical implications

Unexpected cardiac adverse effects are the leading causes of discontinuation of clinical trials and withdrawal of drugs from the market. Since the original observations in the mid-90s, it has been well established that cardiovascular risk factors and comorbidities (such as ageing, hyperlipidaemia, and diabetes) and their medications (e.g. nitrate tolerance, adenosine triphosphate-dependent potassium inhibitor antidiabetic drugs, statins, etc.) may interfere with cardiac ischaemic tolerance and endogenous cardioprotective signalling pathways. Indeed drugs may exert unwanted effects on the diseased and treated heart that is hidden in the healthy myocardium. Hidden cardiotoxic effects may be due to (i) drug-induced enhancement of deleterious signalling due to ischaemia/reperfusion injury and/or the presence of risk factors and/or (ii) inhibition of cardioprotective survival signalling pathways, both of which may lead to ischaemia-related cell death and/or pro-arrhythmic effects. This led to a novel concept of ‘hidden cardiotoxicity’, defined as cardiotoxity of a drug that manifests only in the diseased heart with e.g. ischaemia/reperfusion injury and/or in the presence of its major comorbidities. Little is known on the mechanism of hidden cardiotoxocity, moreover, hidden cardiotoxicity cannot be revealed by the routinely used non-clinical cardiac safety testing methods on healthy animals or tissues. Therefore, here, we emphasize the need for development of novel cardiac safety testing platform involving combined experimental models of cardiac diseases (especially myocardial ischaemia/reperfusion and ischaemic conditioning) in the presence and absence of major cardiovascular comorbidities and/or cotreatments.

Protective Effects of Dexrazoxane against Doxorubicin-Induced Cardiotoxicity: A Metabolomic Study

Cardioprotection of dexrazoxane (DZR) against doxorubicin (DOX)-induced cardiotoxicity is contentious and the indicator is controversial. A pairwise comparative metabolomics approach was used to delineate the potential metabolic processes in the present study. Ninety-six BALB/c mice were randomly divided into two supergroups: tumor and control groups. Each supergroup was divided into control, DOX, DZR, and DOX plus DZR treatment groups. DOX treatment resulted in a steady increase in 5-hydroxylysine, 2-hydroxybutyrate, 2-oxoglutarate, 3-hydroxybutyrate, and decrease in glucose, glutamate, cysteine, acetone, methionine, asparate, isoleucine, and glycylproline.DZR treatment led to increase in lactate, 3-hydroxybutyrate, glutamate, alanine, and decrease in glucose, trimethylamine N-oxide and carnosine levels. These metabolites represent potential biomarkers for early prediction of cardiotoxicity of DOX and the cardioprotective evaluation of DZR.

Alleviation of doxorubicin–induced hepatorenal toxicities with sesamin via the suppression of oxidative stress

Hepatorenal toxicities are an important side effect of anthracycline antibiotics. The objective of this study was to determine whether sesamin (Ses) protects against acute doxorubicin (DOX)-induced hepatorenal toxicities. Rats received daily treatment with either 0.5% carboxymethylcellulose (10 mL/kg) or Ses (10, 20 and 40 mg/kg) orally for 10 days, followed by an intravenous injection at day 8 of either saline (10 mL/kg) or DOX (20 mg/kg). Hepatorenal toxicity was assessed by measuring the levels of serum creatinine (Cre), blood urea nitrogen (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP). The protein expression of 4-hydroxynonenal (4-HNE) in hepatorenal tissues was evaluated using immunohistochemistry. The malondialdehyde (MDA) content and antioxidant activity in the kidney and liver tissues were also measured. The results suggest that pretreatment with Ses ameliorated DOX-induced liver and kidney injury by lowering the serum ALT, AST, ALP, Cre and BUN levels ( p < 0.05 or p < 0.01), and the histological damage to the liver and kidney tissues induced by DOX compared to control were also significantly attenuated by Ses. Furthermore, Ses significantly decreased the DOX-induced increase of MDA and 4-HNE and increased the activity of CAT, SOD and GPX compared to the DOX-treated rats ( p < 0.05 or p < 0.01), whereas the change of DOX + Ses (10 mg/kg) group is not significant compared to the DOX-treated group ( p > 0.05). These findings indicate that Ses elicits a typical protective effect against DOX-induced acute hepatorenal toxicity via the suppression of oxidative stress.

Dihydromyricetin prevents cardiotoxicity and enhances anticancer activity induced by adriamycin

Adriamycin, a widely used anthracycline antibiotic in multiple chemotherapy regimens, has been challenged by the cardiotoxicity leading to fatal congestive heart failure in the worst condition. The present study demonstrated that Dihydromyricetin, a natural product extracted from ampelopsis grossedentat, exerted cardioprotective effect against the injury in Adriamycin-administrated ICR mice. Dihydromyricetin decreased ALT, LDH and CKMB levels in mice serum, causing a significant reduction in the toxic death triggered by Adriamycin. The protective effects were also indicated by the alleviation of abnormal electrocardiographic changes, the abrogation of proliferation arrest and apoptotic cell death in primary myocardial cells. Further study revealed that Dihydromyricetin-rescued loss of anti-apoptosis protein ARC provoked by Adriamycin was involved in the cardioprotection. Intriguingly, the anticancer activity of Adriamycin was not compromised upon the combination with Dihydromyricetin, as demonstrated by the enhanced anticancer effect achieved by Adriamycin plus Dihydromyricetin in human leukemia U937 cells and xenograft models, in a p53-dependent manner. These results collectively promised the potential value of Dihydromyricetin as a rational cardioprotective agent of Adriamycin, by protecting myocardial cells from apoptosis, while potentiating anticancer activities of Adriamycin, thus further increasing the therapeutic window of the latter one.

Cardiotoxicity and cardioprotection in childhood cancer

Children diagnosed with cancer are now living longer as a result of advances in treatment. However, some commonly used anticancer drugs, although effective in curing cancer, can also cause adverse late effects. The cardiotoxic effects of anthracycline chemotherapy, such as doxorubicin, and radiation can cause persistent and progressive cardiovascular damage, emphasizing a need for effective prevention and treatment to reduce or avoid cardiotoxicity. Examples of risk factors for cardiotoxicity in children include higher anthracycline cumulative dose, higher dose of radiation, younger age at diagnosis, female sex, trisomy 21 and black race. However, not all who are exposed to toxic treatments experience cardiotoxicity, suggesting the possibility of a genetic predisposition. Cardioprotective strategies under investigation include the use of dexrazoxane, which provides short- and long-term cardioprotection in children treated with doxorubicin without interfering with oncological efficacy, the use of less toxic anthracycline derivatives and nutritional supplements. Evidence-based monitoring and screening are needed to identify early signs of cardiotoxicity that have been validated as surrogates of subsequent clinically significant cardiovascular disease before the occurrence of cardiac damage, in patients who may be at higher risk.

In vivo and in vitro assessment of the role of glutathione antioxidant system in anthracycline-induced cardiotoxicity

The clinical usefulness of anthracycline antineoplastic drugs is limited by their cardiotoxicity. Its mechanisms have not been fully understood, although the induction of oxidative stress is widely believed to play the principal role. Glutathione is the dominant cellular antioxidant, while glutathione peroxidase (GPx) together with glutathione reductase (GR) constitutes the major enzymatic system protecting the cardiac cells from oxidative damage. Therefore, this study aimed to assess their roles in anthracycline cardiotoxicity. Ten-week intravenous administration of daunorubicin (DAU, 3 mg/kg weekly) to rabbits induced heart failure, which was evident from decreased left ventricular ejection fraction and release of cardiac troponins to circulation. However, no significant changes in either total or oxidized glutathione contents or GR activity were detected in left ventricular tissue of DAU-treated rabbits when compared with control animals. GPx activity in the cardiac tissue significantly increased. In H9c2 rat cardiac cells, 24-h DAU exposure (0.1-10 μM) induced significant dose-dependent toxicity. Cellular content of reduced glutathione was insignificantly decreased, oxidized glutathione and GR activity were unaffected, and GPx activity was significantly increased. Neither buthionine sulfoximine (BSO, glutathione biosynthesis inhibitor) nor 2-oxo-4-thiazolidine-carboxylic acid (OTC, glutathione biosynthetic precursor) had significant effects on DAU cytotoxicity. This contrasted with model oxidative injury induced by hydrogen peroxide, which cytotoxicity was increased by BSO and decreased by OTC. In conclusion, our results suggest that the dysfunction of glutathione antioxidant system does not play a causative role in anthracycline cardiotoxicity.

Alleviation of doxorubicin-induced toxicities by anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract in rats and mice

The objective of this study was to investigate the effects of anthocyanin-rich bilberry extract (BE) with highly antioxidative potential against doxorubicin (Dox)-induced toxicity in rat and mouse models. Sprague-Dawley rats treated with Dox (15 mg/kg intraperitoneally) showed marked body weight loss, increased abdominal ascites and serum glutamate oxaloacetate transaminase (GOT) level, serum and cardiac lipid peroxidation, myocardial histopathological damage, and depletion of cardiac glutathione (GSH). Dietary supplementation with 1% BE significantly reduced serum lipid peroxidation and increased cardiac creatine phosphokinase activity and total GSH level compared with the levels in the Dox control rats (P < 0.05). Serum GOT and cardiac lipid peroxide levels did not change significantly after BE treatment. Morphologic examination revealed that Dox-induced myocardial damage was also significantly suppressed in rats fed with the 1% BE diet. Oral administration of 500 mg/kg of BE for 10 days to mice treated with Dox (10 mg/kg) partially restored the Dox-induced changes by increasing red blood cell and bone marrow cell counts, and hemoglobin level. Although the protective effects of BE were insufficient to completely counteract the toxic effects of Dox, these results suggest that BE supplementation provides moderate protection against Dox-induced cardiac and hematopoietic damage.

Proteomic screening of antioxidant effects exhibited by radix Salvia miltiorrhiza aqueous extract in cultured rat aortic smooth muscle cells under homocysteine treatment

AIM OF THE STUDY

Still little is known about the cellular mechanisms that contribute to the attenuated proliferation of aortic smooth muscle cells under the influence of the oxidative stress factors such as homocysteine (Hcy). Thus, we aimed to evaluate whether Salvia miltiorrhiza Bunge (Labiatae), a Chinese medicinal herb widely used in folk medicine for therapy of variety of human cardiovascular disorders would modulate this Hcy promoted growth effect in model animal aortic cells system.

MATERIALS AND METHODS

The Salvia miltiorrhiza roots aqueous extract (SMAE) containing 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenyl lactic acid and salvianolic acid B, as confirmed by narrow-bore HPLC analyses with binary gradient elution was used in variable concentrations for the treatment of the rat aortic smooth muscle A10 cells under Hcy stimulation. Two-dimensional electrophoresis (2-DE) coupled with MALDI-TOF mass spectrometry was applied for the elucidation of protein changes characterizing the response of the rat A10 cells into the Hcy-induced oxidative stress.

RESULTS

This study showed that a low dose (0.015 mg/mL) of the SMAE significantly inhibited growth (>60%, p<0.05) of the Hcy stimulated rat A10 cells. In addition, concentration of intracellular reactive oxygen species (ROS) obviously decreased in the rat A10 cells after its incubation with SMAE in terms of catalase increasing activity. Next, marked down-regulation of protein kinase C beta-1 (PKC beta-1) and phosphorylated mitogen-activated protein kinase (p-MAPK) expression suggest that observed inhibitory effect of the polyphenol-rich SMAE on the Hcy-induced growth of rat A10 cells was realized via the PKC/p44/42 MAPK-dependent pathway. The intensity changes of 10 protein spots in response of the rat A10 cells to the Hcy-induced oxidative damage as alpha-4-tropomyosin, vimentin, F1F0-ATP synthase (beta subunit), glucose regulated protein 75 (GRP75), actin (fragment), prohibitin, capping protein, plakoglobin, endoplasmic reticulum protein (ERp29), and peptidylprolyl isomerase A (PPIase A), were detected with statistical significance (p<0.05). Meanwhile, it was showed that used here SMAE resist carbonylation of specific cytoskeleton and chaperone proteins as vimentin, alpha-4-tropomyosin and GRP75, respectively, leading to phenotype transformations in the rat A10 cells.

CONCLUSION

These data suggest that applied here SMAE exerts its protective effect through circulating ROS suppression and subsequent modulation of protein carbonylation in rat aortic smooth muscle A10 cells. Redox-proteomics protocol highlighted in this study may be applicable in facilitating the assessing potential novel molecular therapeutic targets to reduce cardiovascular risk related with elevated Hcy levels in various human populations and elucidating new mechanisms through which protein functions can be regulated by the redox status with the use of naturally occurring antioxidants.

Thiol Oxidation Induced by Oxidative Action of Adriamycin

To clarify the mechanism of the cardiotoxic action of adriamycin (ADM), the participation of free radicals from ADM in cardiotoxicity was investigated through the protective action of glutathione (GSH) or by using electron spin resonance (ESR). Oxidation of ADM by horseradish peroxidase and H2O2 (HRP-H2O2) was blocked by GSH concentration dependently. Inactivation of creatine kinase (CK) induced during interaction of ADM with HRP-H2O2 was also protected by GSH. Other anthracycline antitumor drugs that have a p-hydroquinone structure in the B ring also inactivated CK, and GSH inhibited the inactivation of CK. These results suggest that ADM was activated through oxidation of the p-hydroquinone in the B ring by HRP-H2O2. Although ESR signals of the oxidative ADM B ring semiquinone were not detected, glutathionyl radicals were formed during the interaction of ADM with HRP-H2O2 in the presence of GSH. ADM may be oxidized to the ADM B ring semiquinone and then reacts with the SH group. However, ESR signals of ADM C ring semiquinone, which was reductively formed by xanthine oxidase (XO) and hypoxanthine (HX) under anaerobic conditions, were not diminished by GSH, but they completely disappeared with ferric ion. These results indicate that oxidative ADM B ring semiquinones oxidized the SH group in CK, but reductive ADM C ring semiquinone radicals may participate in the oxidation of lipids or DNA and not of the SH group.

Anticancer prodrugs of butyric acid and formaldehyde protect against doxorubicin-induced cardiotoxicity

Formaldehyde has been previously shown to play a dominant role in promoting synergy between doxorubicin (Dox) and formaldehyde-releasing butyric acid (BA) prodrugs in killing cancer cells. In this work, we report that these prodrugs also protect neonatal rat cardiomyocytes and adult mice against toxicity elicited by Dox. In cardiomyocytes treated with Dox, the formaldehyde releasing prodrugs butyroyloxymethyl diethylphosphate (AN-7) and butyroyloxymethyl butyrate (AN-1), but not the corresponding acetaldehyde-releasing butyroyloxydiethyl phosphate (AN-88) or butyroyloxyethyl butyrate (AN-11), reduced lactate dehydrogenase leakage, prevented loss of mitochondrial membrane potential (DeltaPsim) and attenuated upregulation of the proapoptotic gene Bax. In Dox-treated mice, AN-7 but not AN-88 attenuated weight-loss and mortality, and increase in serum lactate dehydrogenase. These findings show that BA prodrugs that release formaldehyde and augment Dox anticancer activity also protect against Dox cardiotoxicity. Based on these observations, clinical applications of these prodrugs for patients treated with Dox warrant further investigation.

Adriamycin-induced myocardial toxicity: New solutions for an old problem?

Adriamycin is a potent and broad-spectrum antineoplastic agent that plays a major role in cancer chemotherapy. Unfortunately, its use has been hampered by conventional toxicities and cardiotoxicity manifested by congestive cardiomyopathy. Adriamycin is particularly toxic to heart tissue and constitutes a major cause of morbidity and mortality due to its complex pathogenesis. In this review, the different forms of cardiotoxicity produced by adriamycin as well as the biochemical changes induced by this drug are summarized. Secondly, the current hypotheses proposed to explain adriamycin-induced myocardial damage (the iron and free-radical hypothesis, the metabolic hypothesis, the "unifying hypothesis" and apoptosis) and the attempts to reduce adriamycin-induced myocardial toxicity are discussed (e.g. dose limitation, close cardiac monitoring, alteration of dosage schedules, development of new anthracycline analogs, and the administration of protective agents and liposomal encapsulation). Finally, we summarized our own experimental and clinical experience in ameliorating and or preventing adriamycin-induced cardiotoxicity and the latest attempts to prevent and/or monitor cardiac function. According to this, a combination of usual doses of calcium antagonist drugs plus vitamins A and E seems advisable.

Plantainoside D protects adriamycin-induced apoptosis in H9c2 cardiac muscle cells via the inhibition of ROS generation and NF-κB activation

Plantainoside D (PD), was isolated from the leaves of Picrorhiza scrophulariiflora (Scrophulariaceae). The anti-oxidative activity of PD was evaluated based on scavenging effects on hydroxyl radicals and superoxide anion radicals. Adriamycin (ADR) is a potent anti-tumor drug known to cause severe cardiotoxicity. Although ADR generates free radicals, the role of free radicals in the development of cardiac toxicity has not been understood. This study was undertaken to investigate the protective effect of PD against ADR-induced apoptosis. In vitro, ADR caused dose-dependent toxicity in H9c2 cardiac muscle cells. Pre-treatment of the cardiac muscle cells with PD significantly reduced ADR-induced apoptosis of cardiac muscle cells. PD inhibited the ROS produced by ADR in the cardiac muscle cells. As well, PD increased GSH(glutathione), compared with ADR. In response to ADR, NF-kappaB was activated in H9c2 cells. However the treatment of PD reduced the activation of NF-kappaB. We also observed that the NF-kappaB inhibitor, PDTC, inhibited the cytotoxic effect on ADR-induced apoptosis in cardiac muscle cells. In parallel, IkappaBalpha-dominant negative plasmid-overexpression abrogated ADR-induced apoptosis in H9c2 cardiac muscle cells. In conclusion, these results suggest that Plantaionoside D can inhibit ADR-induced apoptosis in H9C2 cardiac muscle cells via inhibition of ROS generation and NF-kappaB activation. The pure compound PD can be a potential candidate agent which protects cardiotoxicity in ADR-exposed patients.

Protecting against anthracycline-induced myocardial damage: a review of the most promising strategies

Over the last 40 years, great progress has been made in treating childhood and adult cancers. However, this progress has come at an unforeseen cost, in the form of emerging long-term effects of anthracycline treatment. A major complication of anthracycline therapy is its adverse cardiovascular effects. If these cardiac complications could be reduced or prevented, higher doses of anthracyclines could potentially be used, thereby further increasing cancer cure rates. Moreover, as the incidence of cardiac toxicity resulting in congestive heart failure or even heart transplantation dropped, the quality and extent of life for cancer survivors would improve. We review the proposed mechanisms of action of anthracyclines and the consequences associated with anthracycline treatment in children and adults. We summarise the most promising current strategies to limit or prevent anthracycline-induced cardiotoxicity, as well as possible strategies to prevent existing cardiomyopathy from worsening.

Inhibitory effects of rosmarinic acid on adriamycin-induced apoptosis in H9c2 cardiac muscle cells by inhibiting reactive oxygen species and the activations of c-Jun N-terminal kinase and extracellular signal-regulated kinase

Rosmarinic acid (RA) is a naturally occurring polyphenolic and is found in several herbs in the Lamiaceae family, such as, Perilla frutescens. ADR is a potent anti-tumor drug, but is unfortunately potently cardiotoxic. This study was undertaken to investigate the inhibitory effect of RA on ADR-induced apoptosis in H9c2 cardiac muscle cells at a mechanistic level. In vitro, ADR significantly decreased the viabilities of H9c2 cells, and this was accompanied by apoptotic features, such as a change in nuclear morphology and caspase protease activation. RA was found to markedly inhibit these apoptotic characteristics by reducing intracellular ROS generation and by recovering the mitochondria membrane potential (delta psi). In addition, RA reversed the downregulations of GSH, SOD and Bcl-2 by ADR. In the present study, ADR was found to activate c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK), transcriptional factor-activator-protein (AP)-1. We found that c-fos, Jun-B, Jun-D and p-c-Jun were super shifted by ADR, indicating that these proteins have an important role in the ADR-induced AP-1 activation. The inhibitions of JNK and ERK using appropriate inhibitors or dominant negative cell lines reduced ADR-induced apoptosis in H9c2 cardiac muscle cells. Taken together, these results suggest that RA can inhibit ADR-induced apoptosis in H9C2 cardiac muscle cells by inhibiting ROS generation and JNK and ERK activation. Thus, we propose that RA should be viewed as a potential chemotherapeutic that inhibits cardiotoxicity in ADR-exposed patients.

Modulation by Melatonin of the Cardiotoxic and Antitumor Activities of Adriamycin

In this study, we investigated the effects of melatonin on adriamycin-induced cardiotoxicity both in vivo in rats and in vitro, and on the antitumor activities of adriamycin on MDA-231 and NCI breast cancer cells. Rats that received a single intraperitoneal injection of 25 mg/kg adriamycin showed a mortality rate of 86%, which was reduced to 20% by melatonin treatment (10 mg/kg, SC for 6 days). Melatonin attenuated adriamycin-induced body-weight loss, hemodynamic dysfunction, and the morphologic and biochemical alterations caused by adriamycin. Melatonin also reduced adriamycin-induced nuclear DNA fragmentation, as assessed by the comet assay. In addition, the antitumor activity of adriamycin could be maintained using lower doses of this drug in combination with melatonin. Melatonin treatment in the concentration range of 0.1-2.5 mM inhibited the growth of human breast cancer cells. In terms of oncolytic activity, the combination of adriamycin and melatonin improved the antitumor activity of adriamycin, as indicated by an increase in the number of long-term survivors as well as decreases in body-weight losses resulting from adriamycin treatment. These results indicate that melatonin not only protects against adriamycin-induced cardiotoxicity but also enhances its antitumor activity. This combination of melatonin and adriamycin represents a potentially useful regimen for the treatment of human neoplasms because it allows the use of lower doses of adriamycin, thereby avoiding the toxic side effects associated with this drug.

Endurance training attenuates doxorubicin-induced cardiac oxidative damage in mice

BACKGROUND

There is a lack of studies reporting the influence of DOX treatment on chronically exercised animals. This study intended to determine the effect of endurance swimming training on cardiac muscle tolerance to in vivo DOX-induced damage, analyzing the levels of oxidative stress markers, the response of antioxidant system and the expression of 60 and 70 kDa heat shock proteins (HSP).

METHODS

Forty-four Charles River CD1 male mice were randomly assigned to either non-trained placebo (NT+P) and non-trained DOX (NT+DOX) or trained placebo (T+P) and trained DOX (T+DOX). Twenty-four hours after completion of a 14-week training, cardiac ventricles were extracted for biochemical assays of oxidative stress and damage markers, antioxidant enzymes and HSPs.

RESULTS

DOX treatment per se (single 20 mg kg(-1) dose), administrated 24 h after the last exercise bout, elevated (p<0.05) plasma cardiac troponin I (cTnI), HSP60, % oxidized glutathione, thiobarbituric acid reactive substances and carbonyl groups and reduced -SH groups. However, training induced a significant increase (p<0.05) on total and reduced glutathione (GSH), HSP60 expression, and decreased the rise of plasma cTnI as well as cardiac carbonyl groups contents in DOX hearts, when compared to NT+DOX mice. Although catalase activity of T+DOX was significantly higher than T+P, no changes were observed in the activities of superoxide dismutase, glutathione peroxidase and glutathione reductase. Neither DOX nor training induced significant variations in HSP70.

CONCLUSION

Training improved myocardial tolerance to DOX-induced damage. It is likely that the improvement in responses to DOX was related to training-induced increases in GSH and HSP60.

Moderate endurance training prevents doxorubicin-induced in vivo mitochondriopathy and reduces the development of cardiac apoptosis

The objective of this work was to test the hypothesis that endurance training may be protective against in vivo doxorubicin (DOX)-induced cardiomyopathy through mitochondria-mediated mechanisms. Forty adult (6-8 wk old) male Wistar rats were randomly divided into four groups (n = 10/group): nontrained, nontrained + DOX treatment (20 mg/kg), trained (14 wk of endurance treadmill running, 60-90 min/day), and trained + DOX treatment. Mitochondrial respiration, calcium tolerance, oxidative damage, heat shock proteins (HSPs), antioxidant enzyme activity, and apoptosis markers were evaluated. DOX induces mitochondrial respiratory dysfunction, oxidative damage, and histopathological lesions and triggers apoptosis (P < 0.05, n = 10). However, training limited the decrease in state 3 respiration, respiratory control ratio (RCR), uncoupled respiration, aconitase activity, and protein sulfhydryl content caused by DOX treatment and prevented the increased sensitivity to calcium in nontrained + DOX-treated rats (P < 0.05, n = 10). Moreover, training inhibited the DOX-induced increase in mitochondrial protein carbonyl groups, malondialdehyde, Bax, Bax-to-Bcl-2 ratio, and tissue caspase-3 activity (P < 0.05, n = 10). Training also increased by approximately 2-fold the expression of mitochondrial HSP-60 and tissue HSP-70 (P < 0.05, n = 10) and by approximately 1.5-fold the activity of mitochondrial and cytosolic forms of SOD (P < 0.05, n = 10). We conclude that endurance training protects heart mitochondrial respiratory function from the toxic effects of DOX, probably by improving mitochondrial and cell defense systems and reducing cell oxidative stress. In addition, endurance training limited the DOX-triggered apoptosis.

Saeng-Ji-Hwang has a protective effect on adriamycin-induced cytotoxicity in cardiac muscle cells

This study examined the effect of Saeng-Ji-Hwang (SJH: Radix Rehmanniae) on cardiac muscle cells. Adriamycin-exposed H9C2 cardiac muscle cells were treated with a water extract of SJH. The adriamycin induced cell death and caspase-3 activation were significantly inhibited by SJH (2 mg/ml), which can be explained by the increase in Bcl-2 expression and the inhibition of Bax expression. Adriamycin reduced the Mn-SOD protein expression level in H9C2 cardiac muscle cells but a SJH treatment partially but significantly reversed this effect. Manganese (Mn)-TBAP or Mn-TMyM--mitochondria-specific SOD mimetic agent--reduced the adriamycin-induced cytotoxicity. It was also shown that SJH inhibits the release of H2O2 and prevents lipid peroxidation in the presence of adriamycin. This study examined the intracellular GSH level, which showed that adriamycin significantly decreased the intracellular GSH level but SJH increased it. BSO, a selective inhibitor of glutamyl cysteinyl ligase, which is a rate-limiting enzyme in GSH synthesis, did not affect the viability of the cardiac muscle cells. However, a combination of BSO with SJH in the presence of adriamycin reversed the SJH-induced protection. Overall, the results suggest that SJH-associated Mn-SOD and GSH are important factors in the mechanism of the SJH-induced protective mechanism in H9C2 cardiac muscle cells.

Poly(ADP-ribose) polymerase regulates myocardial calcium handling in doxorubicin-induced heart failure

Reactive oxygen and nitrogen species are overproduced in the cardiovascular system in response to the exposure to doxorubicin, a cardiotoxic anticancer compound. Oxidant-induced cell injury involves the activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP) and pharmacological inhibition of PARP has recently been shown to improve myocardial contractility in doxorubicin-induced heart failure models. The current investigation, by utilizing an isolated perfused heart system capable of beat-to-beat intracellular calcium recording, addressed the following questions: (1) is intracellular calcium handling altered in hearts of rats after 6-week doxorubicin treatment, under baseline conditions, and in response to oxidative stress induced by hydrogen peroxide exposure in vitro; and (2) does pharmacological inhibition of PARP with the phenanthridinone-based PARP inhibitor PJ34 affect the changes in myocardial mechanical performance and calcium handling in doxorubicin-treated hearts under normal conditions and in response to oxidative stress. The results showed a marked elevation in intracellular calcium in the doxorubicin-treated hearts which was normalized by pharmacological inhibition of PARP. PARP inhibition also prevented the myocardial contractile disturbances and calcium overload that developed in response to hydrogen peroxide in the doxorubicin-treated hearts. We conclude that PARP activation contributes to the development of the disturbances in cellular calcium handling that develop in the myocardium in response to prolonged doxorubicin exposure.

Protection against doxorubicin cardiomyopathy in rats: role of phosphodiesterase inhibitors type 4

Selective cardiotoxicity of doxorubicin (DOX) remains a significant and dose-limiting clinical problem. The mechanisms implicated are not yet fully defined but may involve the production of reactive oxygen species or expression of cytokines. Although patients with advanced congestive heart failure express elevated circulating levels of tumour necrosis factor-alpha (TNFalpha), little is known about the prognostic importance and regulation of TNF in the heart in cardiac disease states. Here we tested whether the expression of TNFalpha, along with oxidative stress, is associated with the development of DOX-induced cardiomyopathy (DOX-CM) and whether concurrent treatment with taurine (Taur), an antioxidant, or rolipram (Rolp), a TNFalpha inhibitor, offer a certain protection against DOX cardiotoxic properties. DOX (cumulative dose, 12 mg kg(-1)) was administered to rats in six equal (intraperitoneal) injections over a period of 6 weeks. Cardiomyopathy was evident by myocardial cell damage, which was characterized by a dense indented nucleus with peripheral heterochromatin condensation and distorted mitochondria, as well as significant increase in serum levels of creatine kinase and lactate dehydrogenase. DOX also induced an increment (P<0.001) in serum TNF and plasma nitric oxide levels. The extent of left ventricular (LV) superoxide anion, lipid peroxide measured as malondialdehyde, catalase and calcium content were markedly elevated, whereas superoxide dismutase, total and non-protein-bound thiol were dramatically decreased in DOX-treated rats. Exaggeration of DOX-CM was achieved by intraperitoneal injection of lipopolysaccharide (LPS) (1 mg kg(-1)) 18 h before sampling and evaluated by highly significant increase in heart enzymes (P<0.001), oxidative stress biomarkers and TNFalpha production. Pre- and co-treatment of DOX or DOX-LPS rats with Taur (1% daily supplemented in drinking water, 10 days before and concurrent with DOX) or Rolp (3 mg kg(-1), intraperitoneally, one dose before DOX administration then every 2 weeks throughout the experimental period) ameliorated the deleterious effect of both DOX and LPS on the aforementioned parameters. Meanwhile, it is noteworthy that Rolp exhibited a more preferable effect on serum TNFalpha level. Taur and rolipram also restored the myocardial apoptosis induced by DOX. In conclusion, a cumulative dose of DOX affected free radical and TNFalpha production in the heart of an experimental cardiomyopathy animal model. The current results suggest that down-regulation of these radicals and cytokines could be maintained by using the free radical scavenger Taur or, more favourably, the TNFalpha inhibitor Rolp.

La cardiotoxicité des anthracyclines : mécanismes et cibles pharmacologiques de prévention

Anthracyclines are a class of highly potent antitumour agents utilised against haematological and solid tumours. However, their use has been limited by their cardiotoxic adverse effects, which may lead to congestive heart failure. Such cardiac toxicity is directly related to the cumulative (total) dose of anthracyclines received. At the cellular level, many of the molecular mechanisms of anthracycline-induced cardiotoxicity remain obscure. The present review summarises the current knowledge on the production of anthracycline-induced reactive oxygen species, metabolite generation or cell death, and focuses on the molecules used to prevent anthracycline-induced cardiotoxicity.

Acute and severe hypobaric hypoxia-induced muscle oxidative stress in mice: the role of glutathione against oxidative damage

This study intended to analyze: (1) the effects of acute and severe hypoxia exposure on skeletal muscle oxidative stress and oxidative damage markers; (2) the protective role of the antioxidant glutathione against oxidative damage; and (3) the expression of heat shock protein 70 kDa (HSP70) induced by this hypoxic insult. Forty mice were divided into four groups: control + placebo (C+P), hypoxia + placebo (H+P), control + l-buthionine-[ S, R]-sulfoximine (BSO, a GSH-depleting compound) (C+BSO) and hypoxia + BSO (H+BSO). Hypoxia groups were continuously exposed for 24 h to a hypobaric hypoxic environment equivalent to an altitude of 7000 m and sacrificed immediately after. Control groups were maintained at sea level during the experimental protocol. Analyzed biochemical parameters were: reduced (GSH) and oxidized (GSSG) glutathione, thiobarbituric acid reactive substances (TBARS), sulfhydryl protein groups (SH), N-acetyl-beta- d-glucosaminidase (NAG) and HSP70 protein. Hypoxia (H+P) per se, compared to C+P, induced a significant increase in %GSSG (5.68 vs. 1.14%), TBARS (436.7 vs. 227.9 nM), NAG (4.49 vs. 3.35 U/mg) and HSP70 (178.7 vs. 100%). Compared with H+P, H+BSO showed a significant decrease in total glutathione (19.30 vs. 6.13 nmol/mg) and an additional increase in %GSSG (5.68 vs. 11.33%) and in HSP70 expression (178.7 vs. 202.2%). However, no further oxidative damage was observed in H+BSO. These data suggest that acute hypoxia per se might enhance oxidative stress; however, the glutathione system seems to have a modest role in skeletal muscle protection against hypoxia-induced oxidative stress. Moreover, hypoxia and BSO treatment is a sufficient stimulus to promote HSP70 overexpression.

Melatonin stimulates the activity of protective antioxidative enzymes in myocardial cells of rats in the course of doxorubicin intoxication

The study aimed at determining the effect of melatonin on the activity of protective antioxidative enzymes in the heart and of lipid peroxidation products in the course of intoxication with doxorubicin (DOX). The rats were categorized into four groups, receiving: 0.9% NaCl i.p. (NaCl control); melatonin [20 mg/kg body weight (b.w.)] s.c. (control Mel); DOX (2.5 mg/kg b.w.) i.p.; melatonin plus DOX in doses as above. All the substances were administered once in a week for four consecutive weeks. Homogenates of heart tissue were examined for activities of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), levels of reduced glutathione (GSH) and of lipid peroxidation indices (MDA + 4-HDA). Administration of melatonin alone did not induce alterations in levels of MDA + 4-HDA, GSH, or in activity of GPx, SOD or CAT, as compared to the group receiving 0.9% NaCl. GSH levels decreased following DOX but remained at normal levels following DOX and melatonin. The level of MDA + 4-HDA increased following DOX, as compared with the control, a change prevented by the combination of DOX + melatonin. Activities of GPx, SOD and CAT were higher in groups receiving DOX and/or DOX plus melatonin than in control groups. Activity of CAT and the level of GSH in the group receiving DOX plus melatonin were significantly higher than in the group intoxicated with DOX alone. The obtained results demonstrate that, when given in parallel with DOX, melatonin protects cardiomyocytes from damaging effects of the cytostatic drug (reflected by the levels of MDA + 4-HDA). The protective effect resulted, in part from the augmented levels of GSH and from stimulation of CAT activity by melatonin in cardiomyocytes subjected to the action of DOX.

Chemopreventive effect of garlic powder diet in diethylnitrosamine-induced rat hepatocarcinogenesis

This study was conducted to examine the effects of dietary garlic powder at the different levels on preneoplastic foci formation and glutathione (GSH)-dependent detoxifying enzyme activities in rat hepatocarcinogenesis. Male Sprague-Dawley rats were fed with garlic powder supplemented diets (0, 0.5, 2.0 or 5.0%) for 11 weeks, and induced hepatocarcinogenesis by diethylnitrosamine (DEN) and two-thirds partial hepatectomy in medium-term bioassay system. The 2.0 and 5.0% garlic powder diets suppressed the formation of placental GSH S-transferase positive (GST-P(+)) foci in number (49.7 and 63.1% of DEN-treated control group, respectively) and area (44.2 and 63.9% of DEN-treated control group, respectively). Total GSH content in 2.0% garlic powder diet group was 1.2 fold higher than that in DEN-treated control group. GSH S-transferase activity of 2.0% garlic powder diet group was lower than that in DEN-treated control group, and GSH peroxidase (GPx) activity was significantly increased by garlic powder diets (83 and 164% of DEN-treated control group, respectively). GSH reductase activity, however, did not show a noticeable difference among groups. Therefore, the suppression of GST-P(+) foci formation by garlic powder diets could be partly affected by the increase of total GSH content and GPx activity.

Alpha-lipoic acid ameliorates myocardial toxicity induced by doxorubicin

The effect of alpha-lipoic acid (LA) on the cardiotoxicity induced by doxorubicin (DOX) was investigated. A single dose of DOX (15 mg kg(-1), i.p) induced cardiotoxicity manifested biochemically by a significant elevation of serum creatine phosphokinase (CK; EC: 2.7.3.2) and lactate dehydrogenase (LDH; EC: 1.1.1.27) 48 h later. Moreover, cardiotoxicity was further confirmed by the significant increase in lipid peroxides measured as malondialdehyde (MDA), and significant decrease in protein thiols (Protein-SH) content in heart tissues. Administration of LA (100 mg kg(-1)) orally for 5 days before and 2 days after DOX injection produced a significant protection against cardiotoxicity induced by DOX. The amelioration of cardiotoxicity was evident by significant reductions in serum CK and LDH. Moreover, LA prevented the rise of MDA as well as the significant reduction of Protein-SH. These results may suggest that LA has a protective effect against cardiotoxicity induced by DOX and it may, therefore, improve the therapeutic index of DOX.

Attenuation of the acute adriamycin-induced cardiac and hepatic oxidative toxicity by N-(2-mercaptopropionyl) glycine in rats

The protective effect of the synthetic aminothiol, N-(2-mercaptopropionyl) glycine (MPG) on adriamycin (ADR) induced acute cardiac and hepatic oxidative toxicity was evaluated in rats. ADR toxicity, induced by a single intraperitoneal injection (15 mg/kg), was indicated by an elevation in the level of serum glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), creatine kinase isoenzyme (CK-MB), and lactic dehydrogenase (LDH). ADR produced significant elevation in thiobarbituric acid reactive substances (TBARS), indicating lipid peroxidation, and significantly inhibited the activity of superoxide dismutase (SOD) in heart and liver tissues. In contrast, a single injection of ADR did not affect the cardiac or hepatic glutathione (GSH) content and cardiac catalase (CAT) activity but elevated hepatic CAT. Pretreatment with MPG, (2.5 mg/kg) intragastrically, significantly reduced TBARS concentration in both heart and liver and ameliorated the inhibition of cardiac and hepatic SOD activity. In addition, MPG significantly decreased the serum level of GOT, GPT, CK-MB, and LDH of ADR treated rats. These results suggest that MPG exhibited antioxidative potentials that may protect heart and liver against ADR-induced acute oxidative toxicity. This protective effect might be mediated, at least in part, by the high redox potential of sulfhydryl groups that limit the activity of free radicals generated by ADR.

Potential protective role of angiotensin-converting enzyme inhibitors captopril and enalapril against adriamycin-induced acute cardiac and hepatic toxicity in rats

Captopril and enalapril-angiotensin-converting enzyme (ACE) inhibitors-were evaluated for their antioxidative protective action against adriamycin-induced cardiac and hepatic toxicity. Rats were treated with either captopril (10 mg kg(-1)) or enalapril (2 mg kg(-1)) intragastrically (i.g.) daily for 7 days before single intraperitoneal (i.p.) injection with adriamycin (15 mg kg(-1)). The animals were killed 30 h after adriamycin administration. Adriamycin produced significant elevation in thiobarbituric acid reactive substances (TBARS), which is an indicator of lipid peroxidation, and significantly inhibited the activity of superoxide dismutase (SOD) in heart and liver tissues, with a significant rise in the serum levels of glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT), creatine kinase isoenzyme (CK-MB) and lactic dehydrogenase (LDH), indicating acute cardiac toxicity. A single injection of adriamycin did not affect the cardiac or hepatic glutathione (GSH) content or cardiac catalase (CAT) activity, but hepatic CAT activity was elevated. Pretreatment with ACE inhibitors significantly reduced the TBARS concentration in both heart and liver and ameliorated the inhibition of cardiac and hepatic SOD activity. In addition, the ACE inhibitors significantly improved the serum levels of GOT, GPT, CK-MB and LDH in adriamycin-treated rats. Thus, these results suggest that captopril and enalapril possess antioxidative potential that may protect the heart against adriamycin-induced acute oxidative toxicity. This protective effect might be mediated, at least in part, by the limitation of culprit free radicals and the amelioration of oxidative stress.