Abstract
Oral administration of a single dose of β-adrenoceptor agonist clenbuterol (15 mg/kg body weight) to mice resulted in an increased collagen distribution in sub endocardium and myocardium of left ventricle in mice. Abundant collagen accumulation is characteristic in myonecrotic regions and around blood vessels. Hydroxyproline assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of pepsin insoluble collagen confirmed this stimulated collagen proliferation. MMP-activity assay of tissue extract by gelatin in gel zymography demonstrated a significant inhibition of MMP-9 activity in β-agonist treated group. Results suggest that clenbuterol treatment is capable of inducing structural and functional remodelling of extracellular matrix by down regulating MMP-9 activity and thereby cause an impairment of collagen turnover. This may lead to changes in different hemodynamic properties of the tissue including ventricular compliance.
