Abstract: AIM: To study the effects of epimedium pubescens flavonoids (EF) on the skeleton in ovariectomized rats.METHODS: Forty 4.5-month-old Sprague-Dawley female rats were randomly divided into 4 groups. Rats in sham group were sham-operated and treated by daily oral gavage with vehicle.Rats in other three groups were bilaterally ovariectomized (OVX) and treated by either daily oral gavage with vehicle, or diethylstilbestrol (DES) at 22.5 μg·kg^-1·d^-1, or EF at 300 mg·kg^-1·d^-1 for 90 days.Bone histomorphometric analysis of the proximal tibial metaphysis (PTM), fifth lumbar vertebrae (LV5) and tibial shaft (Tx) was performed in undecalcified sections.The left femurwas collected to determine bone weight, contents of calcium (Ca), phosphorus (P) and hydroxyproline.The uterine weight and the uterine luminal epithelial thickness (ULET) were determined.RESULTS: A significant increase in contents of Ca and P of femur was found in EF group.A tendency of increase was found in%Tb.Ar of PTM, but no significant change was found in bone histomorphometric parameters of LV5 and Tx in EF group.EF had no effect on uterine weight and ULET.CONCLUSION: EF can prevent OVX-induced bone mineral loss of femur, but does not prevent bone loss of PTM and LV5.

Key words: epimedium pubescens flavonoids, osteoporosis, bone histomorphometry, ovariectomized rat, cancellous bone, cortical bone