OBJECTIVE: To probe into the effects of Yishen Bugu decoction on bone formation and nitric oxide-cyclic guanosine monophosphate（NO-cGMP） signaling pathway in osteoporotic rats. METHODS: The SD rat model of postmenopausal osteoporosis（PMOP） was established by removing both ovaries. According to the random number table method

the rats were divided into the sham operation group（sham group）

PMOP rat model group（PMOP group）

Yishen Bugu decoction L group

M group and H group（treated with Yishen Bugu decoction 2

4 and 8 mL/kg by gavage

respectively）

and positive control group（treated with estradiol valerate by gavage）. The preoperative and postoperative body mass of rats in each group were compared

and the general state of rats in each group was observed. The content of total alkaline phosphatase（TALP） and serum anti-tartrate acid phosphatase（TRAP） in serum were detected by enzyme-linked immunosorbent assay. Rat bone mineral density was detected by dual-energy X-ray. Hematoxylin and Eeosin staining was used to detect the histomorphological changes of rat femur

and spectrophotometer and radioimmunoassay were used to detect the content of NO and cGMP in rat femoral tissue. The protein expressions of Wnt3a and β-catenin in femur tissue were detected by Western blotting. RESULTS: Compared with the sham group

the body mass of the PMOP group decreased significantly（P<0.05）;compared with the PMOP group

the body mass of the Yishen Bugu decoction L

M

and H groups increased significantly（P<0.05）

with statistically significant differences. The serum TALP content and femoral BMD of the PMOP group were lower than those of the sham group

and the TRAP content was higher than that of the sham group（P<0.05）;the TALP content and femoral BMD in the Yishen Bugu decoction L

M

and H groups were higher than those in the PMOP group

the TRAP content was lower than the PMOP group（P<0.05）

with concentration-dependent manner

the differences were statistically significant. There was no significant difference in serum TALP

TRAP content and femoral BMD between Yishen Bugu decoction H group and positive control group（P>0.05）. Compared with the sham group

the trabecular bone space of rats in the PMOP group became larger and irregular

the thickness was uneven

and the trabecular bone phenotype was thinner. Compared with the PMOP group

the trabecular bone gap of the rats in the Yishen Bugu decoction L

M

and H groups and positive control group decreased to varying degrees

and the thickness of the trabecular bone was uniform and gradually regular. Compared with the sham group

the contents of NO and cGMP in the femoral tissue of the PMOP group increased significantly（P<0.05）;the contents of NO and cGMP in the femoral tissue of Yishen Bugu decoction L

M and H group were lower than those of PMOP group（P<0.05）

the differences were statistically significant. Compared with the sham group

the expressions of Wnt3a and β-catenin proteins in the femoral tissue of the PMOP group were decreased significantly（P<0.05）;the expressions of Wnt3a and β-catenin proteins in the femoral tissue of the Yishen Bugu decoction L

M and H group were higher than those of the PMOP group（P<0.05）

with dose-dependent manner

the differences were statistically significant. CONCLUSIONS: Yishen Bugu decoction can promote bone formation in PMOP rats

possibly by inhibiting the NO-cGMP signaling pathway to inhibit bone resorption.