Preventive Effects of Traditional Chinese (Kampo) Medicines on Experimental Osteoporosis Induced by Ovariectomy in Rats

Preventive effects by traditional Chinese (Kampo) medicines, Unkei-to, Hachimi-jio-gan, and Juzen-taiho-to, on the progress of bone loss induced by ovariectomy in rats were investigated for a period of 49 days. The bone mineral density (BMD) of tibia in ovariectomized (OVX) rats decreased by 20% from those in sham-operated (Sham) rats, with the decrease completely inhibited by the administration of any one of these Kampo medicines or 17β-estradiol. From scanning electron microscopic (SEM) analyses, the surface of a trabecular bone of tibia in OVX rats had a porous or erosive appearance, whereas that of the same bone in Sham rats was composed of fine particles. The administration of three Kampo medicines and 17β-estradiol to OVX rats preserved the fine particle surface of the trabecular bone. These results strongly suggest that any of these three gynecological Kampo medicines is as effective as 17β-estradiol in preventing the development of bone loss induced by ovariectomy in rats.