Abstract: BACKGROUND: Zishen Jiangu Recipe is an in-hospital consensus prescription for the treatment of osteoporosis in Shenzhen Integrative Medicine Hospital. It has achieved good clinical results in the early stage, but its mechanism underlying treatment of osteoporosis is still unclear.  
OBJECTIVE: To investigate the therapeutic effect of Zishen Jiangu Recipe on osteoporosis by in vivo experiments in an ovariectomized rat model.
METHODS:  Eighty female Sprague-Dawley rats were randomly divided into a surgery group (n=68) and a sham surgery group (n=12). Rat osteoporosis models were established by ovariectomy inthe surgery group. Three months after the surgery, six rats were randomly selected from each group to test the bone mineral density. After successful modeling, the remaining 62 rats in the surgery group were randomly divided into a model group, a low-dose Zishen Jiangu Recipe group, a medium-dose Zishen Jiangu Recipe group, a high-dose Zishen Jiangu Recipe group, and an alendronate sodium group. Rats in low, medium-, and high-dose Zishen Jiangu Recipe groups were given Zishen Jiangu Recipe at doses of 9.375, 18.75, and 37.5 g/kg per day, respectively. Rats in the alendronate group were given 1.02 g/kg alendronate per day, and rats in the sham surgery and model groups were given an equal volume of normal saline by gavage. After 3 months of intervention, rats in each group were killed after anesthesia, and the tibia was separated for Micro-CT bone scan, hematoxylin-eosin histopathological staining and bone mineral density detection. The femur was taken and subjected to a three-point bending test. And the levels of serum alkaline phosphatase, osteocalcin, and tartrate resistance acid phosphatase 5b were determined by enzyme-linked immunosorbent assay. This experiment was approved by the Animal Ethics Committee of Guangzhou University of Chinese Medicine.  
RESULTS AND CONCLUSION: Three months after ovariectomy, the bone mineral density of the rats in the surgery group was significantly reduced, which confirmed that the osteoporosis model was successfully established. After 3 months of intervention, compared with the model group, the levels of serum alkaline phosphatase, osteocalcin, and tartrate resistance acid phosphatase 5b were significantly reduced in the medium- and high-dose Zishen Jiangu Recipe groups and the alendronate group, indicating that Zishen Jiangu Recipe could reduce the high turnover state of the bone in ovariectomized rats. After the intervention, the bone mineral density, the number and thickness of bone trabeculae were increased, the distance between the bone trabeculae was reduced, and the bone strength was significantly increased in the medium- and high-dose Zishen Jiangu Recipe groups. These findings indicate that Zishen Jiangu Recipe can improve bone microstructure, increase bone mineral density, and reduce the risk of fractures.

Key words: osteoporosis, Zishen Jiangu Recipe, bone mineral density, bone microstructure, biomechanics, bone metabolism