The preventive effect of Salvia miltiorrhiza extracts (SMEs) on the progress of bone loss induced by ovariectomy (OVX) was studied in rats. We measured body weight and bone histomorphometry in sham, OVX or SMEs-administered OVX rats. From light microscopic analyses, a porous or erosive appearances were observed on the surface of trabecular bone of tibia in OVX rats, whereas those of the same bone in sham rats and in SMEs-administered rats were composed of fine particles. The trabecular bone area and trabecular thickness in OVX rats decreased by 50% from those in sham rats, these decreases were completely inhibited by administration of SMEs for 7 weeks. In this study, the mechanical strength in femur neck was significantly enhanced by the treatment of SMEs for 7 weeks. In OVX rats, free T3 was normal in all cases, whereas free T4 was significantly increased. Although there was no difference between OVX and SMEs-administered rats in T3 level, we have found significant difference between them in T4 level. These results strongly suggest that SMEs are effective in preventing the development of bone loss induced by OVX in rats.

Dang-Gui-Ji-Hwang Yeum (DGJHY; an Oriental prescription), has been successfully used for the management of osteoporotic disorders in China, Japan and Korea. In this study, we have characterized the effect of DGJHY on osteoporosis-associated phenomena in ovariectomized (OVX) rats by measuring body weights and bone histomorphometries in sham, OVX and DGJHY-administered OVX rats. Light microscopic analyses showed a porous or an eroded appearance on the tibial trabecular bone surface in OVX rats, whereas those of the sham and DGJHY-administered OVX rats were composed of fine particles. The trabecular bone area and the trabecular thickness in OVX rats were significantly lower than those of sham rats. Moreover, these reductions in OVX rats were significantly reversed by the administration of DGJHY for 7 weeks, and osteoclast numbers were also significantly reduced. Although no differences were observed between OVX and DGJHY-administered OVX rats and the sham animals at the T3 level, we have found significant differences between these two groups at the T4 level. However, serum phosphorus, calcium, mechanical strength and the surface appearance of osteoblasts in the DGJHY-administered OVX rats were similar to those of OVX rats. These results suggest that DGJHY is effective at preventing bone loss in OVX rats.