| Objective To observe the effects of Xuling-Jiangu formula combined with alendronate on bone mineral density (BMD), structure, bone metabolism, and EphB4/ephrinB2 signal pathway in ovariectomized rats with rapid bone loss, and to explore its mechanism. Methods Fifty female SD rats were randomly divided into 5 groups: sham operation group, model group, Xuling-Jiangu formula group, alendronate group, and combined treatment group. Postmenopausal osteoporosis model was established with bilateral ovariectomy. After 12 weeks of drug intervention, BMD of the femur was measured using dual energy X-ray absorptiometry. The microstructure of the tibia was observed with HE staining. The levels of serum C-terminal cross linked peptide (S-CTX) and type I procollagen N-terminal propeptide (PINP) were detected with ELISA. The expression levels of EphB4, ephrinB2 mRNA and protein in the lumbar spine were detected with real-time PCR and Western blotting. Results Compared to those in the sham operation group, BMD in the model group decreased significantly (P<0.001), the bone trabeculae were sparse and disordered, and the contents of S-CTX and PINP increased (P<0.01). The expression levels of EphB4, ephrinB2 mRNA and protein in bone tissue decreased significantly (P<0.001). Compared to that in the model group, BMD in the three drug groups increased, and it was the best in the combined drug group (P<0.001). The trabeculae were dense and arranged regularly, the content of S-CTX decreased in varying degrees, and the content of PINP increased in varying degrees. The expression levels of EphB4, ephrinB2 mRNA and protein increased. Conclusion Xuling-Jiangu formula combined with alendronate may improve bone microstructure and serum bone metabolism by activating EphB4/ephrinB2 signal pathway, so as to improve BMD and to play an anti-osteoporosis role in rats. |