An Experimental Study of Pathogenesis of Steroid-induced Avascular Necrosis of Femoral Head

摘要

Objective: To explore the pathogenesis of avascular necrosis of femoral head (ANFH) and search an effective method for clinical practice. Methods: Twenty-four Japanese rabbits were divided into 2 groups of models and controls. ANFH models were produced by intramuscular-injection of large dosage of steroid to rabbits for 8 weeks. From the 4th, 8th and 12th week after production of models, 2 rabbits of each group were sacrificed to observe the structure of femoral head through light microscope and scanning electron microscope. The contents of Nitric Oxide (NO), tissue-type plasminogen activator (t-PA) and -plasminogen activator inhibitor (PAI) in plasma of the 4 rabbits in each group were estimated at the same time. Results: Compared with control group, the rabbits of model group exhibited many differences: such as osteoporosis of femoral head, the presence of more bone lacuna and fat cell through light microscope observing; the broken and sunk bone trabecula, the loosen and broken collagen fibers on the surface of bone matrix through scanning electron microscope observing. Compared with control group, the Concentration of NO and t-PA in plasma of the model rabbits decreased obviously, but the Concentration of the PAI increased obviously. Conclusion: The steroid-induced ANFH might be related to the lower level of NO and the descent of fibrinolytic activity.