Prevention of bone loss in ovariectomized rats:: The effect of Salvia miltiorrhiza extracts

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 T-3 was normal in all cases, whereas free T-4 was significantly increased. Although there was no difference between OVX and SMEs-administered rats in T-3 level, we have found significant difference between them in T-4 level. These results strongly suggest that SMEs are effective in preventing the development of bone loss induced by OVX in rats.