Figure 6: Immunohistochemical analysis showing induction of cathepsin K in femoral bone tissue sections of ovariectomized (OVX) mice administrated with milk thistle extract (MTE) and silibinin. OVX mice were orally administrated with 10 mg/kg/day MTE or 10 mg/kg/day silibinin daily for 8 weeks. Immunohistochemical staining was conducted using a primary antibody of mouse cathepsin K (brown staining, arrows). Representative images were visualized under light microscopy, and brown staining intensity was measured (3 separate experiments). Magnification: 40-fold. Staining intensity values (mean ± SEM, ) in bar graphs not sharing a letter indicate significant difference at .