Objective: To investigate the effects of Bushen Tongluo decoction (BTD) on mRNA expression of receptor activator of NF-κΒ lingand (RANKL)/osteoprotegerin system (OPG) in the osteoporosis rats by bilateral ovariotomy and explore the molecular mechanism of treating osteoporosis with BTD. Method: Rat model of the osteoporosis was established by bilateral ovariotomy. The rats were divided into six groups randomly:the sham operated group

model group

Xianling Gubao group(5.0 g·kg-1)

Bushen decoction group(5.4 g·kg-1)

Tongluo decoction group(0.9 g·kg-1)

BTD group(6.3 g·kg-1). After ten weeks treatment. The mRNA expression of OPG and RANKL in L3 bone tissues was analyzed by RT-PCR. Result: BTD group

Bushen decoction group and Tongluo decoction group could reduce RANKL mRNA expression

decrease the ratio of RANKL/OPG compared with model group

and there was significant difference(P<0.01).The effect of BTD was superior to Bushen decoction and Tongluo decoction(P<0.05). Conclusion: The effect and related mechanism of BTD in the treatment of primary osteoporosis may be related to regulation of RANKL mRNA and improve RANKL/OPG ratio

thereby inhibiting osteoclast activity and reducing bone resorption.