Effect of flavonoid on PGE2-induced alterations in percentage collagen synthesis in ossicle organ cultures.

In adult guinea-pig stapes organ cultures, 3H (2,3)-proline incorporation into the collagenase-digestible protein (CDP) and non-collagen protein (NCP) fractions of the ossicles was measured and the percentage of collagen synthesis (PCS) was calculated. Prostaglandin E2 (PGE2), a potent stimulator of bone resorption, inhibited the PCS in low concentrations (5 and 25 microM), whereas it stimulated it in pharmacological concentrations (50 and 100 microM). Ipriflavon, an isoflavone derivative of therapeutical potential in otosclerosis, also reduced the PCS in 1, 10 and 50 microM concentrations. 50 microM Ipriflavon stimulated the PCS inhibited by 5 microM PGE2, but decreased the PGE2-induced PCS enhancement in vitro.