OBJECTIVETo explore the role of metabolism of fatty substance and osteoclast activity during the process of steroid-induced necrosis of femoral head through mice model inducing and model index measurement.

METHODSForty SD male mice were divided into 2 groups randomly, the control group and the experiment group. After the gluteal injection of colibacillus endotoxin,the experiment group was given gluteal injection of prednisolone acetate 35.5 mg/kg per week, and 2 ml of normal saline to the control group. The mice were killed 12 weeks later and tested the content of Trap-5b, TC and TG of the blood serum. Vitodynamics, bone density were measured and sections of HE staining, Ca2+ and TRACP staining was made then statistic analysis was performanced.

RESULTSThe content of TC, TG and Trap-5b increased apparently (P < 0.01). Large amount of osteoclasts were found in local medullary cavity. There was severe bone loss and decrease of vitodynamics in subchondral bone (P < 0.01) in experiment group.

CONCLUSIONMetabolic disorder of fatty substance is the key pathogenesis of steroid-induced avascular necrosis of femoral head. Decrease of vitodynamics in subchondral bone due to hyperactivity and increase of osteoclast lead to collapse of femoral head directly.