Bone Abstracts

Long-term use of pharmacological treatments of osteoporosis is currently a controversial subject within the scientific community.

The aim of this work was to study the effects produced by a preventive long duration treatment of strontium ranelate and zoledronic acid on bone mass and remodelling when they are administered to ovariectomized rats.

Sixty female albino Wistar rats were divided into four groups (n=15): SHAM group (simulated surgery), OVX group (ovariectomized rats), OVX+ZA (ovariectomized rats treated with Zoledronic acid, 0.08 mg/kg, i.v., at the start of the study), OVX+SR (OVX rats treated with 0.033 g/kg per day of strontium ranelate, oral gavage). Treatments started the day after ovariectomy, and were administered during 8 months. After sacrifice, bone mineral density (BMD) in lumbar spine and femur by DXA and osteocalcin (BGP), aminoterminal propeptide of procollagen I (PINP), 5b isoenzyme of serum tartrate resistant acid phosphatase (TRAP) and carboxiterminal telopeptide of collagen I (CTX) by ELISA were performed.

Femoral and lumbar BMD were significantly decreased in OVX rats without significant differences with those of rats treated with SR. Femoral and lumbar BMD of (OVX+ZA) group was significantly increased with respect to those of OVX group and even with respect to SHAM group. OVX produced a significant increase in BGP, PINP and CTX/TRAP rate. Levels of BGP of (OVX+SR) and (OVX+ZA) groups were similar to those of SHAM group. PINP levels of (OVX+SR) group were similar to those of SHAM group, being levels of (OVX+ZA) group lower than those of SHAM rats. Levels of CTX/TRAP of both treated groups were increased with respect to SHAM group and similar to those of OVX rats, being levels of group treated with ZA significantly lower than those of rats treated with SR.

Conclusions: A long duration preventive treatment with SR was not able to avoid the negative effects of ovariectomy on bone mass. Treatment with ZA avoided these effects and improve bone mass with respect to that of control group.