BACKGROUND:The rabbits were widely used as experimental animal models in the research on etiology and pathological mechanism of steroid-induced osteonecrosis of the femoral head. It is stil a valuable and realistic research topic to improve and to innovate the modeling technology nowadays. OBJECTIVE:To improve the modeling technology on osteonecrosis of the femoral head in rabbits induced by glucocorticoid combined with lipopolysaccharide, with the focus on its reduced mortality and the guaranteed successful rate of modeling. METHODS:A total of 28 New Zealand white rabbits were randomly divided into the control group (n=10) and improvement group (n=18). Models of steroid-induced osteonecrosis of the femoral head were established according to different methods. In the improvement group, rabbits were injected with sodium penicilin (5.0 mg/kg) and amikacin sulfate (1.63×104 U/kg) in the left gluteus muscle. Twenty-four hours later, al rabbits were injected with prednisolone acetate (20 mg/kg) in the right gluteus muscle. Forty-eighthours later, 5.0 μg/kg of lipopolysaccharide was intravenously injectedvia the ear. From then on, two injections of prednisolone acetate (20 mg/kg) were respectively performed alternately in the left and right gluteal muscle at an interval of each 24 hours. Sodium penicilin (5.0 mg/kg) and amikacin sulfate (1.63×104 U/kg) were intraperitonealy injected for 2 consecutiveweeks. In the control group, 10 μg/kg lipopolysaccharide was injectedvia the ear vein of rabbit. From then on, prednisolone acetate (20 mg/kg) was intramuscularly injected at an interval of each 24 hours, totaly three times. Benzylpenicilin sodium 20×104 U/rabbit was intramuscularly injected once a week. RESULTS AND CONCLUSION:Rabbit models of steroid-induced osteonecrosis of the femoral head were successfuly established in both groups. Compared with the control group, the mortality was significantly reduced after model establishment in the improvement group, and the bone lacuna and osteonecrosis of the femoral head were apparent. These findings indicated that the improved technology of model establishment of steroid-induced osteonecrosis of the femoral head could be used to aleviate the damage degree on the gluteal muscles, to guarantee the successful rate of modeling, and to noticeably reduce the mortality of rabbits.

1), attributable risk (AR)=13.33%; ⑤Even though the serum specimens were taken from PB patients, the Ab of majouity of patients converted to positive when relapse occurred. In the majority of patients relapsed the levels of IgM-AbL tended to be increasing or pesistently positive. Usually relapse occurred 1-2 years after IgM-AbL was converted to positive. Relapse occurred 11-30 years after the patients were cured. In very rare case downgrading(from tuberculous to borderline leprosy) occurred. ⑥The levels of IgM-AbL gradually decreased in all relapsed patients after effective treatment except one case whose IgM-AbL was persistently positive. Conclusions The above results indicate that the ND-ELISA might be useful in screening early M.leprae infection and in predicting and monitoring the relapse of leprosy, especially in multibacillary patients.