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Collagen degradation in ischaemic rat hearts
S Takahashi1, A C Barry, S M Factor
1Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, NY 10461.
The Biochemical Journal
|January 1, 1990
Summary
Myocardial infarction rapidly degrades collagen in the extracellular matrix. Increased collagenase and neutral proteinase activity likely causes this rapid breakdown of cardiac tissue structure.
Area of Science:
- Cardiovascular Biology
- Biochemistry
- Extracellular Matrix Research
Background:
- The myocardial extracellular matrix provides structural support to cardiac cells.
- Alterations in this matrix are implicated in ventricular dysfunction post-ischemic injury.
Purpose of the Study:
- To investigate the rapid changes in collagen content within the myocardial extracellular matrix following ischemic injury.
- To identify potential enzymatic mechanisms responsible for collagen degradation during myocardial infarction.
Main Methods:
- Induction of myocardial infarction in rats by ligating the left anterior descending coronary artery for 1-3 hours.
- Quantification of total collagen content in infarct zones and control tissues.
- Assay of collagenase, neutral proteinase, and lysosomal serine proteinase activities.
Main Results:
- Significant and rapid collagen loss observed in myocardial infarct zones within 1-3 hours of ligation (collagen content reduced to 50-75% of controls).
- Decreased insoluble collagen content suggests degradation of stable collagen fibers.
- Increased activities of collagenase (3-fold), neutral proteinases (3-fold), and lysosomal serine proteinases (2-fold) were detected in infarct tissues.
Conclusions:
- Rapid degradation of myocardial extracellular matrix collagen occurs during early stages of myocardial infarction.
- Elevated collagenase and neutral proteinase activities are likely key contributors to this accelerated collagen breakdown.