Analyses of serum biochemistry, morphology and histopathology of the control, Dmp1 KO, and the KO with Hi-Pi diet for two months. (A-C) Serum biochemistry profiles of the 3-month-old control (left columns), KO (middle columns), and KO with Hi-P treatment (right columns) groups revealed an effective rescue of the level of Pi (A), but not the levels of Ca (B) or FGF23 (C); Data are presented as “MEAN±SEM”; n=5; *P<0.05; compared to the control. (D-E) The representative radiographs (D) and μ-CT (E) images of the 3-month-old mouse knees displayed a full rescue of the overall structure in the KO+Hi-Pi group (right panels). (F) Representative safranin-O stained images displayed staining loss in the KO articular cartilage but re-involved in the KO+Hi-Pi specimen (right). (G) The H&E stain images revealed subchondral bone sclerosis (asterisks), osteophyte (arrowhead) and an cyst (arrow) in the KO knee joint, plus a apparent restoration of the histological structures in the 1-year-old KO+Hi-Pi group (right panel).