oxytocin and Cardiomyopathies

Doxorubicin-induced (DXR) cardiomyopathy is a serious health issue in oncology patients. Effective treatment of this clinical situation still remains to be discovered. In this experimental animal study, we aimed to define therapeutic effects of liraglutide, oxytocin and granulocyte colony-stimulating factor in DXR-induced cardiomyopathy model. 40 male Sprague-Dawley rats were included to study. 32 rats were given doxorubicin (DXR) for cardiomyopathy model. DXR was administered intraperitonally (i.p.) at every other day of 2.5 mg/kg/day at six times. Eight rats were taken as normal group and no treatment was performed. 32 rats given doxorubicin were divided into 4 groups. Group 1 rats were assigned to a placebo group and was given with a 0.9% NaCl saline solution at a dose of 1 ml/kg/day i.p. (DXR + saline), Group 2 rats were given with 1.8 mg/kg/day of Liraglutide i.p. (DXR + LIR), Group 3 rats were given with 160 μg/kg/day oxytocin i.p. (DXR + OX), Group 4 rats were given with 100 μg/kg/day filgrastim i.p. (DXR + G-CSF). All medications were given for 15 days. On day 16, under anesthesia, ECG was recorded from derivation I. After that, blood samples were taken by tail vein puncture for biochemical analysis. Finally, the animals were euthanized and the heart removed and prepared for immunohistochemical examination. All three treatments were shown to ameliorate the toxic effect of doxorubicin in cardiac tissue with the best results in DXR + OX group. DXR + OX group had the most preserved tissue integrity examined by light microscopy, least immune expression level of CASPASE-3 (5.3 ± 0.9) (p < 0.001) the highest ECG QRS wave voltage amplitude (0.21 ± 0.008 mV) (p < 0.00001) least plasma MDA (115.3 ± 19.8 nm) (p < 0.001), TNF-alpha (26.6 ± 3.05 pg/ml) (p < 0.001), pentraxin-3 (2.7 ± 0.9 ng/ml) (p < 0.001), Troponin T (1.4 ± 0.08 pg/ml) (p < 0.001), pro-BNP (11.1 ± 3.6 pg/ml) (p < 0.001) levels among all three treatment groups. Consistent with previous literature, we found that OX treatment decreased oxidative, apoptotic and inflammatory activity in DXR-induced cardiomyopathy rat model as well as provided better tissue integrity and better results in clinically relevant measures of ECG assessment, plasma Troponin T and pro-BNP levels. LIR and G-CSF treatment caused similar results with less powerful effects. Our findings suggest that with the best results in OX treatment group, all three agents including LIR and G-CSF attenuates DXR-induced cardiomyopathy in

Topics: Animals; Apoptosis; C-Reactive Protein; Cardiomyopathies; Cardiotoxicity; Caspase 3; Disease Models, Animal; Doxorubicin; Granulocyte Colony-Stimulating Factor; Heart Rate; Humans; Inflammation Mediators; Lipid Peroxidation; Liraglutide; Malondialdehyde; Myocytes, Cardiac; Natriuretic Peptide, Brain; Oxidative Stress; Oxytocin; Rats, Sprague-Dawley; Serum Amyloid P-Component; Signal Transduction; Troponin T; Tumor Necrosis Factor-alpha

Oxytocin (OT) is involved in the regulation of energy metabolism and in the activation of cardioprotective mechanisms. We evaluated whether chronic treatment with OT could prevent the metabolic and cardiac abnormalities associated with diabetes and obesity using the db/db mice model. Four-week-old male db/db mice and their lean nondiabetic littermates (db/+) serving as controls were treated with OT (125 ng/kg · h) or saline vehicle for a period of 12 weeks. Compared with db/+ mice, the saline-treated db/db mice developed obesity, hyperglycemia, and hyperinsulinemia. These mice also exhibited a deficient cardiac OT/natriuretic system and developed systolic and diastolic dysfunction resulting from cardiomyocyte hypertrophy, fibrosis, and apoptosis. These abnormalities were associated with increased reactive oxygen species (ROS) production, inflammation, and suppressed 5'-adenosine monophosphate kinase signaling pathway. The db/db mice displayed reduced serum levels of adiponectin and adipsin and elevated resistin. OT treatment increased circulating OT levels, significantly reduced serum resistin, body fat accumulation (19%; P<.001), fasting blood glucose levels by (23%; P<.001), and improved glucose tolerance and insulin sensitivity. OT also normalized cardiac OT receptors, atrial natriuretic peptide, and brain natriuretic peptide, expressions and prevented systolic and diastolic dysfunction as well as cardiomyocyte hypertrophy, fibrosis, and apoptosis. Furthermore, OT reduced cardiac oxidative stress and inflammation and normalized the 5'-adenosine monophosphate-activated protein kinase signaling pathway. The complete normalization of cardiac structure and function by OT treatment in db/db mice contrasted with only partial improvement of hyperglycemia and hyperinsulinemia. These results indicate that chronic treatment with OT partially improves glucose and fat metabolism and reverses abnormal cardiac structural remodeling, preventing cardiac dysfunction in db/db mice.

Topics: Adiponectin; Animals; Blood Glucose; Cardiomyopathies; Diabetes Mellitus, Type 2; Energy Metabolism; Hyperinsulinism; Insulin Resistance; Male; Mice; Obesity; Oxytocin; Resistin

Regular physical activity is beneficial in preventing the risk of cardiovascular complications of diabetes. Recent studies showed a cardioprotective role of oxytocin (OT) to induce natriuretic peptides (NPs) and nitric oxide (NO) release. It is not known if the diabetic state is associated with a reduced OT-NPs-NO system and if exercise training improves this system. To address this, we investigated the effects of treadmill running using the db/db mouse model of type 2 diabetes. Eight-week-old db/db mice were subjected to running 5 days per week for a period of 8 weeks. The lean db/+ littermates were used as controls. Sedentary db/db mice were obese and hyperglycaemic, and exercise training was not effective in reducing body weight and the hyperglycaemic state. Compared to control mice, db/db mice had lower heart weight and heart-to-body weight ratios. In these mice, this was associated with augmented cardiac apoptosis, cardiomyocyte enlargement and collagen deposits. In addition, db/db mice displayed significant downregulation in gene expression of OT (76%), OT receptors (65%), atrial NP (ANP; 43%), brain NP (BNP; 87%) and endothelial nitric oxide synthase (eNOS) (54%) in the heart (P < 0.05). Exercise training had no effect on expression of these genes which were stimulated in control mice. In response to exercise training, the significant increment of anti-apoptotic Bcl-2 gene expression was observed only in control mice (P < 0.05). In conclusion, downregulation of the OT-NPs-NO system occurs in the heart of the young db/db mouse. Exercise training was not effective in reversing the defect, suggesting impairment of this cardiac protective system in diabetes.

Topics: Animals; Base Sequence; Cardiomyopathies; Diabetes Complications; Diabetes Mellitus, Type 2; Disease Models, Animal; DNA Primers; Down-Regulation; Genes, bcl-2; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Natriuretic Peptides; Nitric Oxide Synthase Type III; Oxytocin; Physical Conditioning, Animal; Physical Exertion; Receptors, Oxytocin; Risk Factors