Influence of osteoprotegerin (OPG) on experimentally induced ectopic bone

In this paper the effect of osteoprotegerin (OPG) on slowing down the resorption process of heterotopically induced bone tissue is described. The induced ossicle is resorbed ex inactivitate. This system is analogous to osteoporosis in immobilised skeletal bones. Bone induction was achieved in BALB/c mice after injection of a suspension of 3 x l0(6) HeLa cells into thigh muscle of animals immuno-suppressed by a single dose ofhydrocortisone. To slow down the process of induced bone resorption, OPG was administered and the effect was measured quantitatively by weighing the mass of the induced ossicle after hydrolysis of soft tissues surrounding the induced ossicles. As an effect of the application of OPG, dry bone mass of the induced ossicles exceeded 340-540% of the values of the control specimens following 9 applications of0.05 mg OPG per mouse every second day or 14 doses every day.