An experimental study on the effects of glucocorticoid on hip bone

[Objective]To study the effects of high dosage of methylprednisolone on acetabulum,caput ossis femoris and proximal femurs in a rabbit model by expression of BMP-2.[Method]Twenty-seven adult rabbits were divided into three groups.Besides control group(group A),experimental groups were consisted group B and group C,with 9 rabbits in each group.The animal model of osteonecrosis of the femoral head(ONFH) was established by intramuscular injection of methylprednisolone sodium succinate 80 mg/kg/d in rabbits,for 3 days in group B,for 6 days in group C.At 2,4,8 weeks after steroid administration,the bone tissue of caput ossis femoris and proximal femurs were collected and the changes of expression of BMP-2 were observed.[Result]The average percentage of dyed areas and average optical density of BMP-2 had a trend of decreasing with time and dosages increased in group B,C.No dyed areas was observed in individual samples(P0.05).[Conclusion]High dosages of methylprednisolone can lead to osteonecrosis of femoral head and proximal femurs,reduce the expression of BMP-2.The higher the dosages of methylprednisolone are administered and the longer the administering time lasts,the poorer of the bone of hip and the proximal femur will be.