ABSTRACT
<p><b>OBJECTIVE</b>To study the therapeutic effects of Rhizoma Drynariae and estrogen on osteoporosis in ovariectomized (OVX) rats.</p><p><b>METHODS</b>Fifty-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.</p><p><b>RESULTS</b>Compared 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.</p><p><b>CONCLUSION</b>Rhizoma Drynariae has the similar effect with estrogen in maintaining normal trabecular structure and connection by inhibiting the increased bone turnover of postmenopausal osteoporosis.</p>