Objective:To examine the effects of compound piracetam(P-S) in preventing cancellous bone loss in ovariectomized(ovx)rats.Methods:Thirty eight female Sprague-dawley rats of four months old were randomly divided into five groups:the basal control(BAS

n=6)

sham+saline(SHAM

n=8)

ovx+saline(OVX

n=8)

ovx+diethylstilbestrol 30 μg/(kg·d)(OVX+DES

n=8)

and ovx+Piracetam 432 mg/(kg·d)+ stanozolol 0.54 mg/(kg·d)(OVX+P-S

n=8).Rats were treated by oral gavage for 90 days.The basal control were sacrificed at day 0;other groups were killed 90 days later.Left tibias were harvested and examined by both static and dynamic histomorphometry.Results:Compared with the sham-operated group

trabecular bone area(%Tb.Ar)

trabecular thickness(Tb.Th)

trabecular number(Tb.N) and percent labeled perimeter(%L.Pm) were significantly decreased(all P<0.01);trabecular separation(Tb.Sp)

osteoclast number per millimeter(Oc.N)

and percent osteoclast surface perimeter(% Oc.Pm) in OVX rats were significantly increased(all P<0.01);additionally

bone formation rate/bone volume(BFR/BV) was increased(P<0.05).Compared with the OVX group

both diethylstilbestrol and compound piracetam increased %Tb.Ar(P<0.01 and P<0.01

respectively)

Tb.Th(P>0.05 and P<0.05 respectively) and Tb.N(P<0.01 and P<0.01 respectively)

but Tb.Sp was decreased(P<0.01 and P<0.01 respectively).Compared with the OVX+DES group

compound piracetam increased Tb.Th and %L.Pm(both P<0.05).Conclusion:Like the effects of diethylstilbestrol

compound piracetam can prevent cancellous bone loss in ovx rats.The mechanism may be that compound piracetam promotes bone formation and inhibits bone absorption.