ABSTRACT
Doxorubicin (DOX) is the mainstay chemotherapeutic agent against a variety of human neoplasmas. However, its clinical utility is limited by its marked cardiotoxicity. Chrysin, is a natural flavone which possesses antioxidant, anti-inflammatory and anti-cancer properties. The current study aimed to investigate the potential protective effect of chrysin against DOX-induced chronic cardiotoxicity and the underlying molecular mechanisms. Male Sprague-Dawley rats were treated with either DOX (5 mg/kg, once a week) and/or chrysin (50 mg/kg, four times a week) for four weeks. Chrysin prevented DOX-induced cardiomyopathy which was evident by conduction abnormalities, elevated serum CKMB and LDH and histopathological changes. Chrysin also ameliorated DOX-induced oxidative stress by decreasing lipid peroxidation and upregulating the antioxidant enzymes. Moreover, chrysin attenuated DOX-induced apoptosis via decreasing expression of p53, Bax, Puma, Noxa, cytochrome c and caspase-3 while increasing expression of Bcl-2. DOX induced activation of MAPK; p38 and JNK and increased expression of NF-κB. Meanwhile, DOX suppressed AKT pathway via decreasing expression of its upstream activator VEGF and increasing expression of PTEN. Conversely, chrysin effectively neutralised all these effects. Collectively, these findings indicate that chrysin effectively protected against DOX-induced cardiomyopathy via suppressing oxidative stress, p53-dependent apoptotic pathway, MAPK and NF-κB pathways while augmenting the VEGF/AKT pathway.
Subject(s)
Antioxidants/pharmacology , Cardiomyopathies/prevention & control , Cardiotonic Agents/pharmacology , Flavonoids/pharmacology , Gene Expression Regulation/drug effects , Myocytes, Cardiac/drug effects , Animals , Apoptosis/drug effects , Apoptosis Regulatory Proteins/genetics , Apoptosis Regulatory Proteins/metabolism , Cardiomyopathies/chemically induced , Cardiomyopathies/genetics , Cardiomyopathies/pathology , Cardiotoxicity/prevention & control , Caspase 3/genetics , Caspase 3/metabolism , Cytochromes c/genetics , Cytochromes c/metabolism , Doxorubicin/toxicity , Drug Administration Schedule , Male , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/pathology , NF-kappa B/genetics , NF-kappa B/metabolism , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-bcl-2/genetics , Proto-Oncogene Proteins c-bcl-2/metabolism , Rats , Rats, Sprague-Dawley , Signal Transduction , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolism , bcl-2-Associated X Protein/genetics , bcl-2-Associated X Protein/metabolism , p38 Mitogen-Activated Protein Kinases/genetics , p38 Mitogen-Activated Protein Kinases/metabolismABSTRACT
BACKGROUND: Retinopathy of prematurity (ROP) is one of the targets for early detection and treatment to prevent childhood blindness in world health organization programs. The purpose of study was to evaluate the efficacy of intravitreal injection of 2-Methoxyestradiol (2-ME) nanoemulsion in regressing neovascularization of a ROP rat model. METHODS: A prospective comparative case - control animal study conducted on 56 eyes of 28 healthy new born Sprague Dawley male albino rat. ROP was induced in 21 rats then two concentrations of 2-ME nanoparticles were injected in right eyes of 14 rats (low dose; study group I, high dose; study group II). A blank nanoemulsion was injected in the right eyes of seven rats (control positive group I). No injections performed in contralateral left eyes (control positive group II). Seven rats (14 eyes) were kept in room air (control negative group). On postnatal day 17, eyeballs were enucleated. Histological structure of the retina was examined using Hematoxylin and eosin staining. Vascular endothelial growth factor (VEGF) and glial fibrillary acidic protein (GFAP) expressions were detected by immunohistochemical studies. RESULTS: Intravitreal injection of 2-ME (in the two concentrations) caused marked regression of the new vascular tufts on the vitreal side with normal organization and thickness of the retina especially in study group II, which also show negative VEGF immunoreaction. Positive GFAP expression was detected in the control positive groups and study group (I). CONCLUSION: Intravitreal injection of 2-Methoxyestradiol nanoemulsion is a promising effective method in reduction of neovascularization of a ROP rat model.
Subject(s)
Estradiol/analogs & derivatives , Retinal Neovascularization/drug therapy , Retinal Vessels/pathology , Retinopathy of Prematurity/drug therapy , 2-Methoxyestradiol , Animals , Animals, Newborn , Disease Models, Animal , Disease Progression , Estradiol/administration & dosage , Immunohistochemistry , Intravitreal Injections , Male , Photomicrography , Prospective Studies , Rats , Rats, Sprague-Dawley , Retinal Neovascularization/diagnosis , Retinal Neovascularization/etiology , Retinopathy of Prematurity/complications , Retinopathy of Prematurity/pathology , Tubulin Modulators/administration & dosage , Vascular Endothelial Growth Factor A/antagonists & inhibitorsABSTRACT
Doxorubicin (DOX) is a widely used chemotherapeutic agent however its clinical use is limited by cumulative cardiotoxicity. Epigallocatechin-3-gallate (EGCG), a main catechin in green tea, possesses a potent antioxidant, anti-apoptotic and anticancer properties. The current study aimed to investigate the potential protective effect of EGCG against DOX-induced cardiotoxicity. Firstly the potential cardioprotective dose of EGCG was screened at different doses (10, 20 and 40 mg/kg/day) against a single dose of DOX (15 mg/kg; i.p.). EGCG protected against DOX-induced ECG changes, leakage of cardiac enzymes (creatine kinase isoenzyme-MB, and lactate dehydrogenase) and histopathological changes. The dose of 40 mg/kg EGCG was selected for further assessment to address the EGCG cardioprotective mechanisms. EGCG was given orally 3 times/week for 4 consecutive weeks and DOX (2.5 mg/kg; i.p.) 3 times/week on the last 2 weeks. EGCG significantly ameliorated oxidative stress injury evoked by DOX as evidenced by inhibition of reduced glutathione depletion and lipid peroxidation as well as elevation of antioxidant enzyme activities. DOX caused down-regulation of ErbB2 expression while EGCG pretreatment significantly increased ErbB2 expression indicating its effect on pro-survival pathway. Furthermore, DOX provoked apoptotic responses evidenced by increasing the expression of nuclear factor kappa-B, tumor suppressor protein p53, calpain 2, caspases 3 and 12. Additionally basal level of Hsp70 was reduced in DOX-intoxicated group. EGCG pretreatment significantly ameliorated these apoptotic signals indicating its anti-inflammatory and anti-apoptotic actions. In conclusion, EGCG possesses cardioprotective action against DOX-induced cardiotoxicity by suppressing oxidative stress, inflammation and apoptotic signals as well as activation of pro-survival pathways.