The animals were housed in an air-conditioned room (21–24 °C) under 12 h of light (7:00–19:00) and were allowed free access to food pellets and water throughout the study. Animal experiments Female mice were anesthetized with sodium pentobarbital (40 mg/kg, i.p.) for see more the bilateral removal of the ovaries. The mice in the sham-operated group were anesthetized, laparotomized, and sutured without removal of the ovaries. After 3 days of recovery from surgery, the OVX mice were randomly divided into four groups and orally treated with

vehicle (H2O), kinsenoside (100 and 300 mg/kg daily), or alendronate (2.5 mg/kg every other day; Sigma-Aldrich, St. Louis, MO, USA) for 4 weeks. The sham-operated group was orally treated with H2O only. Plasma ALP levels were measured using clinical kits (Roche Diagnostics, Mannheim, Germany) and a spectrophotometric system (Cobas Mira; Roche, Rotkreuz, Switzerland). Plasma CTx levels were determined using a mouse-specific enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s protocols (Nordic Bioscience Diagnostics, Herlev Hovedgade, Denmark). Microtomography analysis was performed as reported previously [20]. The trabecular bone microarchitecture of the distal right femoral metaphysis was measured using a microtomography scanner (SkyScan

1076, Kontizh, Belgium), with Ku 0059436 an isotropic resolution of 18 μm in all three spatial dimensions. Acetophenone Bone volume and tissue volume were measured directly from the original three-dimensional images, and trabecular bone volume (bone volume/tissue volume, percent) was calculated by dividing the bone volume by the total volume of interest. Other parameters of trabecular structure were studied, including thickness, separation, and the number of trabeculae, as calculated directly from three-dimensional images. The left femur was removed, fixed with 4 % neutral-buffered paraformaldehyde in phosphate-buffered saline

(PBS; pH 7.4) for 48 h, and decalcified in 10 % ethylenediamine tetraacetic acid solution (pH 7.4) at 4 °C for 4 weeks. After decalcification, each bone sample was cut along the coronal plane, embedded in paraffin, and cut longitudinally into sections for histological staining. For measurement of the osteoclast number, sections were stained for tartrate-resistant acid phosphatase (TRAP) with TRAP kit (Sigma-Aldrich, St. Louis, MO, USA) as previously described [21]. To explore the mechanisms associated with kinsenoside on OVX-induced osteoporosis in mice, total RNA of the right tibiae was extracted for analysis of RT-PCR. The expression levels of ALP, matrix metalloproteinase-9 (MMP-9), and TRAP were normalized to that of GAPDH mRNA in the same tissue. The PCR products were separated on a 2 % agarose gel and recorded on Polaroid film; the band was quantified with a densitometer.