LOVASTATIN PREVENTS STEROID-INDUCED ADIPOGENESIS AND OSTEONECROSIS

Osteonecrosis of the femoral head was induced experimentally in chicke ns after the administration of a high dose of corticosteroids. Lovasta tin was used to prevent the effects of the steroid on adipogenesis in cultured cells, and adipogenesis and osteonecrosis in chickens. The in vitro study, with marrow cells in culture, showed that Lovastatin inh ibited steroid induced fat specific gene expression and counteracted t he inhibitory effects of steroids on osteoblastic gene expression, For the in vivo study, 83 adult chickens were used: 48 received methylpre dnisolone 3 mg/kg weekly via intramuscular injection (Group A). Fiftee n received the steroid (as in Group A) plus Lovastatin 20 mg per anima l per day orally (Group B), Ten chickens received Lovastatin only (Gro up C), Another 10 received no medication and served as the control gro up (Group D). Evidence of osteonecrosis was observed in specimens from Group A, including subchondral bone death and resorption, fat cell pr oliferation, and new hone formation. Conversely, sections from Group B showed less adipogenesis and no bone death. It is concluded that the bipedal chicken is a useful animal model for studies of osteonecrosis and that lipid clearing agents, such as Lovastatin, may be helpful in preventing the development of steroid induced osteonecrosis.