Attenuation by metallothionein of early cardiac cell death via suppression of mitochondrial oxidative stress results in a prevention of diabetic cardiomyopathy

J Am Coll Cardiol. 2006 Oct 17;48(8):1688-97. doi: 10.1016/j.jacc.2006.07.022. Epub 2006 Sep 27.


Objectives: We aimed to test whether attenuation of early-phase cardiac cell death can prevent diabetic cardiomyopathy.

Background: Our previous study showed that cardiac apoptosis as a major early cellular response to diabetes is induced by hyperglycemia-derived oxidative stress that activates a mitochondrial cytochrome c-mediated caspase-3 activation pathway. Metallothionein (MT) as a potent antioxidant prevents the development of diabetic cardiomyopathy.

Methods: Diabetes was induced by a single dose of streptozotocin (STZ) (150 mg/kg) in cardiac-specific, metallothionein-overexpressing transgenic (MT-TG) mice and wild-type (WT) controls. On days 7, 14, and 21 after STZ treatment, cardiac apoptosis was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and caspase-3 activation. Cardiomyopathy was evaluated by cardiac ultrastructure and fibrosis in the diabetic mice 6 months after STZ treatment.

Results: A significant reduction in diabetes-induced increases in TUNEL-positive cells, caspase-3 activation, and cytochrome c release from mitochondria was observed in the MT-TG mice as compared to WT mice. Cardiac protein nitration (3-nitrotyrosine [3-NT]) and lipid peroxidation were significantly increased, and there was an increase in mitochondrial oxidized glutathione and a decrease in mitochondrial reduced glutathione in the WT, but not in the MT-TG, diabetic mice. Double staining for cardiomyocytes with alpha sarcomeric actin and caspase-3 or 3-NT confirmed the cardiomyocyte-specific effects. A significant prevention of diabetic cardiomyopathy and enhanced animal survival were observed in the MT-TG diabetic mice as compared to WT diabetic mice.

Conclusions: These results suggest that attenuation of early-phase cardiac cell death by MT results in a significant prevention of the development of diabetic cardiomyopathy. This process is mediated by MT suppression of mitochondrial oxidative stress.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Antioxidants / metabolism*
  • Apoptosis / drug effects
  • Cardiomyopathies / etiology
  • Cardiomyopathies / prevention & control*
  • Caspase 3 / metabolism
  • Cell Death
  • Cytochromes c / metabolism
  • Diabetes Mellitus, Experimental / complications*
  • Diabetes Mellitus, Experimental / metabolism
  • Diabetes Mellitus, Experimental / pathology
  • Diabetes Mellitus, Experimental / physiopathology
  • Enzyme Activation
  • Glutathione / antagonists & inhibitors
  • Glutathione Disulfide / metabolism
  • Lipid Peroxidation
  • Metallothionein / genetics
  • Metallothionein / metabolism*
  • Mice
  • Mice, Transgenic / genetics
  • Mitochondria, Heart / metabolism*
  • Myocardium / metabolism
  • Myocardium / pathology
  • Myocytes, Cardiac*
  • Oxidative Stress*
  • Sarcomeres / metabolism
  • Survival Analysis
  • Tyrosine / analogs & derivatives
  • Tyrosine / metabolism


  • Actins
  • Antioxidants
  • 3-nitrotyrosine
  • Tyrosine
  • Cytochromes c
  • Metallothionein
  • Caspase 3
  • Glutathione
  • Glutathione Disulfide