Objective: To investigate the effect of two treating principles and formulas

named 'invigorating spleen to remove phlem and promoting blood circulation to remove meridian obstruction’(Jianpi) and 'invigorate the kidney and promoting blood circulation to remove meridian obstruction’(Bushen)

on the expression of osteoprotegerin(OPG) and receptor activator of nuclear factor-κB ligand(RANKL) mRNA in steroid-induced osteonecrosis of the femoral head(SONFH)

as well as to explore and compare their mechanism of prevention and treatment for SONFH. Method: Sixty-four chickens were randomly divided into control group

model group

Jianpi group and Bushen group. Except the control group

the animal model of SONFH was established with injection of methylprednisolone in chest muscle of chickens. At 8th and 16th weeks

both sides of femoral heads were taken off to observe the expression of OPG and RANKL mRNA with in situ hybridization staining. Result: Compared with the control group

the expression of OPG mRNA was decreased and RANKL mRNA increased significantly in model group(P<0.01). Compared with model group

both in Jianpi and Bushen group

the expression of OPG mRNA was increased and RANKL mRNA decreased significantly

meanwhile the ratio of OPG to RANKL was increased(P<0.01 or P<0.001). In Bushen group

the change did not obvious at the 8th weeks

however

the changes were significant compared with that in Jianpi group at the 16th weeks. Conclusion: Both Jianpi and Bushen formula can regulate the expression of OPG and RANKL mRNA to inhibit bone destruction

thereby exert preventive and therapeutic effect for SONFH. Jianpi take action earlier than Bushen formula.