THE
EFFECT OF FK506 ON STEROID-INDUCED OSTEONECROSIS IN RABBITS
Miyanishi
K, Yamamoto T, Irisa T, Yamashita A, Motomura G, Jingushi S, Noguchi
Y, Iwamoto Y
Department of Orthopaedic Surgery, Graduate School of Medical Sciences,
Kyushu University, Fukuoka Japan
We assessed the effect of FK506 (FK) on steroid-induced osteonecrosis (ON) in rabbits. Rabbits were given 0.1 mg/kg FK intramuscularly for 15 days and were injected once with either 20 mg/kg (Group A, n=20) or 2.2 mg/kg (Group B, n=15) steroid after the second injection of FK. Forty rabbits were given physiologic saline (PS) intramuscularly for 15 days and were injected once with 20 mg/kg steroid after the second injection of PS (Control, Group C). At 4 weeks after steroid injection, both femora and humeri were histopathologically examined for ON. Incidence of ON was 85%, 33% and 80% in Groups A-C, respectively. FK did not decrease the incidence of ON when same doses of steroid were given. The incidence was significantly decreased when decreased dose of steroid was given with FK. Clinically reported decreased incidence of ON in patients treated with FK may be caused by decreased dose of steroid used, not by FK itself.