[Efficacy and mechanism of low glycoside from Epimedii Folium flavonoids on retinoic acid-induced osteoporosis in rats].

In this study, the secondary osteoporosis model was induced by oral administration of retinoic acid for two weeks in SD male rats. The efficacy and mechanism of LG on secondary osteoporosis in rats were explored through the bone morphogenetic protein 2(BMP-2)/Runt-related transcription factor 2(Runx2)/Osterix signaling pathway. With Xianling Gubao Capsules(XLGB) as the positive control, three dose groups of low glycoside from Epimedii Folium flavonoids(LG), i.e., low-dose group(LG-L), medium-dose group(LG-M), and high-dose group(LG-H), were set up. After modeling, the rats in each group were treated correspondingly by gavage for eight weeks. The action target of LG in the treatment of secondary osteoporosis in rats was analyzed by measuring the body weight and the organ indexes of rats including heart index and testis index. The efficacy of LG was characterized by the pathological changes of the femur, the microstructural parameters of the trabecular bone, and the biomechanical properties of femoral tissues in rats. The mechanism of LG was explored by measuring the relevant biochemical indexes and the changes in BMP-2, Runx2, and Osterix content in rats with secondary osteoporosis. The results showed that the action target of LG in the treatment of secondary osteoporosis in rats was the testis. LG can improve the bone loss of the femur, increase the number and thickness of the trabecular bone, reduce the porosity and separation of the trabecular bone, potentiate the resistance of bone to deformation and destruction, up-regulate the serum content of Ca, P, aminoterminal propeptide of type Ⅰ procollagen(PINP), and osteocalcin(OC), promote bone matrix calcification and the expression of BMP-2, Runx2, and Osterix proteins, and accelerate bone formation, thereby reducing the risk of fractures, and ultimately exerting anti-secondary osteoporosis efficacy.