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Exercise attenuates diabetes-induced ultrastructural changes in rat cardiac tissue
Yvonne M Searls1, Irina V Smirnova, Barbara R Fegley
1Departments of Anatomy & Cell Biology, University of Kansas Medical Center, Kansas City, KS, USA.
Medicine and Science in Sports and Exercise
|October 30, 2004
Summary
Endurance exercise partially reverses cardiac ultrastructural damage in diabetic cardiomyopathy. Exercise improved mitochondria and extracellular matrix in diabetic rats, but not nuclear or myofibrillar changes.
Area of Science:
- Cardiology
- Diabetology
- Exercise Physiology
Background:
- Cardiovascular disease is a major complication of Type I diabetes.
- Diabetic cardiomyopathy involves significant ultrastructural changes in the heart.
- Exercise is a recognized nonpharmacological intervention for cardiovascular health.
Purpose of the Study:
- To investigate the impact of endurance exercise on cardiac ultrastructure in a rat model of Type I diabetes.
- To determine if exercise can mitigate or reverse diabetes-induced myocardial changes.
Main Methods:
- Type I diabetes was induced in 7-week-old rats using streptozotocin.
- Animals were divided into sedentary non-diabetic, sedentary diabetic, and exercised diabetic groups.
- Exercised diabetic rats underwent daily treadmill running for 9 weeks.
- Heart ultrastructure was analyzed via transmission electron microscopy.
Main Results:
- Diabetes induced left ventricular changes including myofibrillar disarray, mitochondrial damage, increased lipid accumulation, and collagen fiber alterations.
- Diabetic cardiomyocytes showed nuclear abnormalities like heterochromatin changes and membrane invaginations.
- Exercise significantly attenuated diabetes-induced collagen fibril, cytoplasmic area, and mitochondrial damage.
Conclusions:
- Endurance exercise partially restores specific ultrastructural features of diabetic cardiomyopathy.
- Exercise favorably impacts mitochondria and extracellular matrix components in diabetic hearts.
- Exercise did not significantly alter myofibril density, lipid accumulation, or nuclear morphology in this model.