RESUMEN
OBJECTIVE:To study the effect of catalpol on the activity and apoptosis of osteoclasts (OC) in the osteoblasts (OB)-OC co-culture system and its mechanism. METHODS:OB and OC were isolated respectively from the SD rats of 1-3 days and 5-7 days old to establish OB-OC co-culture system. After treated with 0(blank control),0.05,0.5,5,50 and 100 mg/L catal-pol for 48,72 and 96 h,the number of bone absorption lacuna for OC was observed by inverted microscope to reflect OC activity. After treated with 0(blank control)and 0.05 mg/L catalpol for 48,72 and 96 h,the activity of tartrate resistant acid phosphatase (TRACP)in OC was detected,and the apoptosis rate of OC was calculated. After treated with 0(blank control)and 0.05 mg/L ca-talpol,mRNA expression of osteoprotegerin(OPG)in OB was detected. RESULTS:In OB-OC co-culture system,the number of bone absorption lacuna in 0.05-50 mg/L catalpol groups was significantly lower than blank control group(P<0.01),indicating ca-talpol could inhibit OC activity,especially 0.05 mg/L catapol. Compared with blank control,0.05 mg/L catapol lowered the activity of TRACP but increased the apoptosis rate of OC(P<0.05);mRNA expression of OPG was up-regulated in OB(P<0.01). CON-CLUSIONS:In OB-OC co-culture system,catalpol can inhibit the activity of OC and induce the apoptosis of OC,and its mecha-nism may be associated with the mRNA expression up-regulation of OPG in OB.