OBJECTIVE: To analyze the effects of Hormone Replacement Therapy on the biomechanical and tomographic evaluation of femurs of rats submitted to induced menopause. METHODS: Forty-five adult Wistar rats were divided equally into three groups. The first and second groups consisted of rats submitted to oophorectomy, and the third was the control group, consisting of non-oophorectomized rates. After observing hormonal failure (exfoliative cytology), only the first group received HRT, over a two-month period. After this period, the femurs were disarticulated and submitted to biomechanical tests in a universal testing machine to evaluate stamina, and submitted to tomographic evaluation to determine mineral bone density. RESULTS: The exfoliative cytology showed induction of hormonal failure in all the animals oophorectomized. A significant difference (p=0.030) was observed between the groups in the measurements of maximum stamina, which was higher in the group with HRT. Greater bone fragility was observed in the oophorectomized animals that did not receive HRT, compared with those that received HRT (p=0.010) in relation to the control group (p=0.0107). There was in increase in bone strength in the oophorectomized rats with HRT compared with those without HRT, and similar values to the control group (p = 1.179). In the tomographical evaluation, no significant differences were found between the groups (p=0.625). CONCLUSION: A significant increase in bone strength was observed with the use of HRT. However, treatment with HRT did not show any significant alteration in bone mineral density.
Menopause; Hormone replacement therapy; Tomography; Bone and bones; Osteoporosis; Femur; Rats
