| Objective To explore the mechanism of action of the warming and tonifying kidney-yang prescription Jingang Pills in intervening postmenopausal osteoporosis from the perspective of Th17/Treg cell immune balance. Methods Forty female SD rats were divided into the sham operation group, the model group, the estradiol valerate group (0.1 mg·kg?1·d?1), the equivalent-dose Jingang Pills group (3.6 g·kg?1·d?1), and the high-dose Jingang Pills group (7.2 g·kg?1·d?1) according to the random number table method, with 8 rats in each group. The bilateral ovariectomy was used to establish the model. After 3 months of drug intervention, the bilateral femurs, spleens and blood of the rats were collected. Micro-CT was used to detect the bone microstructure. Tartrate-resistant acid phosphatase staining (TRAP) was used to observe the number of osteoclasts. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of interleukin-17 (IL-17) and interleukin-10 (IL-10) in the serum. Flow cytometry was used to detect the proportion of Th17/Treg cells in the blood and spleen of rats. Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB) were respectively used to detect the mRNA and protein expressions of ROR-γt and Foxp3 in bone tissues. Results Compared to the model group, Jingang Pills can significantly increase the bone mineral density (BMD), bone volume fraction (BV/TV), and trabecular number (Tb.N) of bone tissues in ovariectomized rats (P＜0.01), decrease the trabecular separation (Tb.SP) (P＜0.01), and improve the trabecular structure. Meanwhile, Jingang Pills canreduce the number of osteoclasts in the bone tissues of ovariectomized rats. Additionally, Jingang Pills can significantly decrease the level of IL-17and increase the level of IL-10 in serum of ovariectomized rats (P＜0.01). Furthermore, Jingang Pills can significantly lower the ratio of CD4+IL-17A (Th17) in the blood and spleen of ovariectomized rats, and increase the ratio of CD4+CD25+Foxp3 (Treg) (P＜0.01). Moreover, Jingang Pills can significantly reduce the mRNA and protein expression levels of ROR-γt in the femur, and increase the mRNA and protein expression levels of Foxp3 (P＜0.01). Conclusion Jingang Pills can effectively reduce bone loss in ovariectomized rats by inhibiting the activity of osteoclasts, and its mechanism of action is closely related to the regulation of Th17/Treg cell balance. |