OPN, BSP, and Bone Quality-Structural, Biochemical, and Biomechanical Assessment in OPN, BSP, and DKO Mice.

Osteopontin (OPN) and Bone Sialoprotein (BSP), abundantly expressed by osteoblasts and osteoclasts, appear to have important, partly overlapping functions in bone. In gene-knockout (KO, -/-) models of either protein and their double (D)KO in the same CD1/129 genetic background, we analyzed the morphology, matrix characteristics, and biomechanical properties of femur bone in 2 and 4 month old, male and female mice. OPN mice display inconsistent, perhaps localized hypermineralization, while the BSP are hypomineralized throughout ages and sexes, and the low mineralization of young DKO mice recovers with age.