Calcitonin versus clodronate in the prevention of ovariectomy-induced osteopenia in rats

The effects of salmon calcitonin and clodronate were compared in ovariectom ised rats. Sixty female Wistar rats (similar to 260 g in weight) were fed t he same diet and had the same living conditions. The rats were divided into the following groups: 15 rats with sham ovariectomy and no drug treatment (Sham-OVX); 45 rats with bilateral ovariectomy subdivided into 15 rats not receiving drug treatment (OVX group), 15 rats treated with subcutaneous sal mon calcitonin, 2 U/kg/day every 2 days (OVX + CT group) and 15 rats treate d with subcutaneous clodronate, 5 mg/kg/day every 2 days (OVX + Cl group). Sixty days after surgery, the rats were sacrificed and their femurs and fif th lumbar vertebrae were dissected and cleaned of soft tissue. Femur length , vertebral height, and bone mineral content and bone mineral density of th e femur and fifth lumbar vertebra by dual-energy X-ray absorptiometry were measured. Calcitonin had a significant and stronger effect in preventing ov ariectomy-induced osteopenia in the femur (OVX + CT vs OVX groups, p<0.0001 ); both calcitonin and clodronate had a significant effect on the fifth lum bar vertebra, which was greater in the calcitonin group (OVX + CT vs OVX C1 groups, p<0.005). These findings indicate that calcitonin has a protecti ve effect on both the axial (trabecular bone) and peripheral (cortical bone ) skeletons, but clodronate only has a protective effect on the axial skele ton.