Title: EGCG inhibits cardiomyocyte apoptosis in pressure overload-induced cardiac hypertrophy and protects cardiomyocytes from oxidative stress in rats
Abstract: Aim:To investigate the effects of epigallocatechin gallate(EGCG)on pressure overload and hydrogen peroxide(H_2O_2)induced cardiac myocyte apoptosis. Methods:Cardiac hypertrophy was established in rats by abdominal aortic constriction.EGCG 25,50 and 100 mg/kg were administered intragastrically(ig). Cultured newborn rat cardiomyocytes were preincubated with EGCG,and oxida- tive stress injury was induced by H_2O_2.Results:In cardiac hypertrophy induced by AC in rats,relative to the model group,EGCG 25,50 and 100 mg/kg ig for 6 weeks dose-dependently reduced systolic blood pressure(SBP)and heart weight indices,decreased malondialdehyde(MDA)content,and increased superoxide dismutase(SOD)and glutathione peroxidase(GSH-PX)activity,both in serum and in the myocardium.Also,treatment with EGCG 50 and 100 mg/kg markedly improved cardiac structure and inhibited fibrosis in HE and van Gieson(VG)stain, and reduced apoptotic myocytes in the hypertrophic myocardium detected by terminal transferase-mediated dUTP-biotin nick end-labeling(TUNEL)assay.In the Western blot analysis,EGCG significantly inhibited pressure overload-induced p53 increase and bcl-2 decrease.In H_2O_2-induced cardiomyocyte injury,when preincubated with myocytes for 6-48 h,EGCG 12.5-200 mg/L increased cell viabil- ity determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)assay.EGCG also attenuated H_2O_2-induced lactate dehydrogenase(LDH) release and MDA formation,Meanwhile,EGCG 50 and 100 mg/L significantly inhibited the cardiomyocyte apoptotic rate in flow cytometry.Conclusion:EGCG inhibits cardiac myocyte apoptosis and oxidative stress in pressure overload in- duced cardiac hypertrophy.Also,EGCG prevented cardiomyocyte apoptosis from oxidative stress in vitro.The mechanism might be related to the inhibitory effects of EGCG on p53 induction and bcl-2 decrease.
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
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Cited By Count: 1
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