OBJECTIVE

This study was performed to investigate bone deteriorations and the involvement of skeletal Eph/ephrin signaling pathway of GIOP aged mice in response to the treatment of genistein.

METHODS

The biomarkers in serum and urine were measured, tibias were taken for the measurement on gene and protein expression and histomorphology analysis, and femurs were taken for the measurement on bone Ca and three-dimensional architecture of trabecular bone.

RESULTS

Genistein showed a greater increase in bone Ca, BMD and significantly increased FGF-23 and OCN, reduced TRACP-5b, PTH and CTX in GIOP mice. Genistein reversed DXM-induced trabecular deleterious effects and stimulated bone remodeling. The treatment of DXM group with genistein significantly elevated the ratio of OPG/RANKL. Moreover, genistein administration down-regulated the mRNA and protein expression of Eph A2 and ephrin A2 in tibia of the GIOP mice. In contrast, the mRNA and protein expression of Eph B4 and ephrin B2 were increased in mice treated by DXM with genistein as compared to the DXM single treatment.

CONCLUSIONS

DXM-induced trabecular bone micro-structure deterioration in aged mice was involved in the regulation of the Eph receptors and ephrin ligands. Genistein might represent a therapy with bone-forming as well as an anti-resorptive activity in GIOP mice. The underlying mechanism was mediated, at least partially, through regulation Eph/ephrin signaling.