关键词: 骨质疏松, 海参皂苷, 去卵巢, 骨生成

Abstract: Objective: To investigate the effect and underlying mechanism of sea cucumber saponin (SCS) on bone mineral density in bilaterally ovariectomized mice. Methods: Female C57BL/6J mice were ovariectomized to establish an osteoporotic animal model. After 4 weeks, the mice were randomly divided into four groups: sham operation (normal saline), model (normal saline), low-dose SCS (7.5 mg/kg mb) and high-dose SCS (15.0 mg/kg mb) groups. After administration for 90 days, the urinary concentrations of Ca and P, bone mineral density (BMD) and mineral apposition rate (MAR) were determined to evaluate the effect of SCS on bone minerals. Furthermore, the relative mRNA expression of biochemical parameters of bone formation (ALP, OCN, Col1a, BMP2) and key genes involved in the Wnt/β-catenin pathway were detected to elucidate the underlying molecular mechanism. Results: SCS significantly inhibited the urinary levels of Ca and P (P < 0.05), and decreased the loss of bone mineral. Dual energy X-ray scanning and fluorescence double labeling results showed that SCS significantly increased BMD and bone mineralization in ovariectomized mice (P < 0.05). Quantitative real-time polymerase chain reaction (qPCR) showed that SCS could decrease the relative mRNA expression of ALP, OCN, Col1a and BMP2 by down-regulating the relative mRNA expression of Wnt10b, LRP5, GSK-3β, β-catenin, Runx2 and OSX, the key genes involved in the Wnt/β-catenin pathway (P < 0.05). Conclusion: SCS can improve osteoporosis by inhibiting the loss of bone mineral, increasing BMD and bone mineralization, inhibiting the activation of the Wnt/β-catenin pathway and consequently limiting the compensatory increase in bone formation.

Key words: osteoporosis, sea cucumber saponin, ovariectomized, bone formation