Sialoglycoprotein from Gadous morhua eggs improve high bone turnover activity via down-regulating BMP-2/Smads and Wnt/β-catenin signal pathways.

ABSTRACT: The effect of sialoglycoprotein isolated from Gadous morhua eggs (Gm-SGP) on ovariectomized (OVX) induced osteoporosis, which is characterized by high bone turnover activity was investigated. Results revealed that Gm-SGP significantly increased bone mineral density, enhanced bone biomechanical properties and repaired the microstructure of the trabecular bone. Also, the treatment with Gm-SGP remarkably decreased biochemical marker contents or activities, such as serum BALP, PICP, BMP-2, TrACP, Cath-K, urine Ca and P, leading to the reduction in bone turnover. The elevation in the rate of bone formative process contributed in the increase of bone turnover. Both BMP-2/Smads and Wnt/β-catenin signaling pathways played an important role in osteogenesis. Gm-SGP suppressed the key factors expression in these two pathways such as BMP-2, Smad1, Smad4, Lrp-5b, Runx2, Osx, ALP, Col1, OCN and β-catenin. These findings might provide some theoretical basis for the application of Gm-SGP as a potential anti-osteoporotic drug or as functional food.