A Japanese herbal medicine, Chujo-to, has a beneficial effect on osteoporosis in rats

The inhibitory effects of a Japanese herbal medicine, Chujo-to, on the prog ress of bone loss induced by ovariectomy in rats were investigated, Ovariec tomized rats were administered with Chujo-to during weeks 7-14 after ovarie ctomy. At 14 weeks, the bone mineral density of the tibia from ovariectomiz ed (OVX) rats had decreased by 27% compared with those in the sham-operated rats, and by a 18%-21% and 16% decrease after the administration of Chujo- to and 17 beta-oestradiol, respectively. The surface of a trabecular bone o f the tibia in ovariectomized rats had a porous and fibrous appearance, whi le that of the same bone in sham-operated rats was composed of fine particl es. After the administration of Chujo-to or 17 beta-oestradiol, the surface of trabecular bone maintained the porous and fibrous appearance, The uteri ne weight was not restored by Chujo-to but by 17 beta-oestradiol, These res ults suggest that Chujo-to has an efficacy on the osteoporosis of rats simi lar to 17 beta-oestradiol, but with a different mechanism. (C) 1999 John Wi ley & Sons, Ltd.