EFFECTS OF ANGIOTENSIN Ⅱ AND ALDOSTERONE ON COLLAGEN METABOLISM OF CULTURED CARDIAC FIBROBLASTS / 解放军医学杂志

ABSTRACT

To explore the influence of angiotensinⅡ(AngⅡ) and aldosterone (Ald) on synthesis of collagen and activity of precollagenase secreted by cardiac fibroblasts.Sirus Red method was employed to evaluate collagen synthesis of cultured cardiac fibroblasts; typeⅠ collagen was measured by competitive ELISA; collagenase activity was tested by fluorescence spectrophotometry.At the doses of 10-9～10-7mol/L, AngⅡ could enhance gross and typeⅠ collagen production in a dose-dependent manner. Collagenase activity decreased with increasing concentration of AngⅡ. These effects of AngⅡcould be completely abolished by its receptor antagonist, saralasin. Ald might enhance gross and typeⅠ collagen production only at a higher concentration (10-7～10-8mol/L), whereas lower concentration (10-9mol/L) had no effect on it. These effects of Ald could be abolished by spironolactone,a specific Ald receptor antagonist. In addition, Ald could significantly decrease the activity of collagenase secreted from cultured cardiac fiboblasts at concentrations of 10-9～10-7mol/L within 24h，which could not be antagonized by 10-6mol/L spironolactone. The results suggested that AngⅡand Ald enhance cardiac fibroblasts collagen synthesis and inhibit collagenase activity ,resulting in net collagen accumulation resulted and acceleration of cardiac fibrosis.