OBJECTIVE: To investigate clinical, biomechanic and histomorphometric effects of zoledronic acid on osteoporotic rats'tibiae after bilateral ooforectomy. METHODS: 40 female Wistar (Rattus novergicus albinus) rats were prospectively studied. On the 60th day of life, the animals were randomized into two groups according to the surgical procedure: bilateral ooforectomy (O) (n=20) and sham surgery ("sham") (P) (n=20). After 30 days, the animals were divided into four groups, according to the administration of zoledronic acid (ZA) 0.1mg/kg or distilled water (DW): OZA (n=10), ODW (n=10), PZA (n=10) and PDW (n=10). After 12 months, the animals were sacrificed, and had their tibiae assessed. In the clinical study, animals'weight was considered; in the biomechanical study, compressive assays were applied and, in the histomorphometric analysis, the bone trabecular area was determined. RESULTS: "O" groups showed a significantly greater weight gain than "P" groups (p=0.005). Groups OZA and PZA showed an insignificant weight gain when compared to ODW (p=0.47) and PDW (p=0.68). The groups receiving zoledronic acid and distilled water were able to bear maximum load, similar (p=0.2), at the moment of fracture. In the groups receiving zoledronic acid, an insignificant increase of the bone trabecular area was found when compared to the groups receiving distilled water (p=0.21). There was a positive correlation between trabecular area and maximum load (p=0.04; r=0.95). CONCLUSION: Zoledronic acid did not significantly influence animals' weight. The results showed an insignificant increase both of the tibial shaft bone resistance and the bone trabecular area.
Osteoporosis; Biomechanics; Tibia; Experimental epidemiology; Wistar rats; Prospective studies
