Effects of total coumarins of Fructus cnidii on skeleton of ovariectomized rats.

Total coumarins of Fructus Cnidii (TCFC), 5 g.kg-1 by intragastric gavage, 6 d/wk, x 7 wk, was effective for prevention of bone loss in ovariectomized (OVX) rats. In comparison to aging control rats, the proximal tibia of placebo-treated OVX rats were characterized by an increase in eroded perimeter (+298%), label perimeter (+77%), osteoid perimeter (+47%), mineral apposition rate (+32%) and bone formation rate (+130%). These changes indicated a high bone turnover in OVX rats leading to a rapid bone loss (-44%) in proximal tibial metaphysis. In contrast, the TCFC-treated OVX rats showed an increase of cancellous bone area (+41%) compared with placebo-treated OVX rats and decrease in all the above indices of bone turnover to near aging control levels except that of the osteoid area (+88%) which was higher than that in aging control, but mineralization lag time did not show significant changes. The results suggested that the TCFC inhibited the high bone turnover and reversed the bone loss at early menopausal stage.