Fig 2: Expression levels of OPG and RANKL in the supernatants of osteoblasts and the serum of rats were measured by the enzyme-linked immunosorbent assay. (A) The serum concentration of OPG in vivo. (B) The serum concentration of RANKL in vivo. (C) The supernatant concentration of OPG in vitro. (D) The supernatant concentration of RANKL in vitro. Values are presented as the mean ± standard deviation. *P<0.05, **P<0.01. OPG, osteoprotegerin; RANKL, receptor activator of nuclear factor-?B ligand; OVX, ovariectomized rats; GaN, gallium nitrate; NS, not significant.

Fig 3: Protein expression levels of OPG and RANKL in bone tissue were measured by western blotting. Data were normalized against ß-actin. (A) The OPG protein relative ratio in vivo. (B) The RANKL protein relative ratio in vivo. (C) The OPG protein relative ratio in vitro. (D) The RANKL protein relative ratio in vitro. Values are presented as the mean ± standard deviation. *P<0.05, **P<0.01. OPG, osteoprotegerin; RANKL, receptor activator of nuclear factor-?B ligand; OVX, ovariectomized rats; GaN, gallium nitrate; NS, not significant.

Fig 4: OPG immunohistochemical staining of proximal tibiae sections in OVX rats treated with or without 120 µg/kg/day of GaN (magnification, ×400). (A) Sham group, (B) OVX group, (C) OVX+GaN group and (D) the IOD mean density of OPG expression. Values are presented as the mean ± standard deviation. *P<0.05, **P<0.01. OPG, osteoprotegerin; OVX, ovariectomized rats; GaN, gallium nitrate; IOD, integrated optical density; NS, not significant.