OBJECTIVETo study the therapeutic effects of Rhizoma Drynariae and estrogen on osteoporosis in ovariectomized (OVX) rats.

METHODSFifty-five female rats were randomly divided into 5 groups, the normal control (normal),the sham operated (sham), the model, the estrogen, and the Rhizoma drynariae (RD) groups; ovariectomized rats were used as postmenopausal osteoporosis model. The changes of morphology and dynamic parameters in different groups were determined by bone histomorphometry.

RESULTSCompared with the model group, the trabecular volume (TBV/TTV) , trabecular thickness (MTPT) and density (MTPD) in the other four groups were significantly increased, while the trabecular template spacing (MTPS) and the ratio of trabecular surface to trabecular volume (TBS/TBV) significantly decreased (P <0. 05); and the osteoid surface (TOS), single label surface [Sfract (s) ] ,double label surface [Sfract (d) ] and bone formation rate (Svf) also decreased,while osteoid maturation period (OMP) increased in the latter four groups. No significant difference of cortical width (MCW) was found between these 5 groups. Compared with the normal and sham groups, TOS, Sfract ( s) , Sfract ( d) , Svf in the estrogen and RD groups increased significantly, while OMP decreased; no significant difference was found in other parameters.

CONCLUSIONRhizoma Drynariae has the similar effect with estrogen in maintaining normal trabecular structure and connection by inhibiting the increased bone turnover of postmenopausal osteoporosis.