Bone Abstracts

Osteoporosis is a multifactorial disease that represents an increase public health problem, given the impact on functional independence and quality of life. Among the favoring factors to the imbalance in bone cell activity, the hypoestrogenism is primordial. Strength training (ST) proves to be effective because of its ability to stimulate estrogen receptor independent of ligand. In this study, we analyzed the action of ST on bone quality of rats during the aging. For this study, 40 females Wistar rats of 18 months were distributed into the groups: G1- Sham G2 – Sham/ST, G3 – (ovariectomized) OVX and G4- OVX/ST. During 120 days (3×/week), the animals Sham/ST and OVX/ST performed exercise with 80% of maxima force. Finite elements and immunohistochemical analysis for Runx2, osterix, osteocalcin and TRAP were realized. The results show that ST was able to stimulate osteoblast differentiation through the positive regulation of Runx2 and osterix, culminating action in favor of bone formation by increasing osteocalcin and decreasing TRAP. This action of ST on bone cells resulted in tougher tissue, which is evident in the finite element analysis. The table below shows the maximum force (N) and the minimum and maximum tension (MPa) of the femoral neck region and demonstrate that given the force applied in OVX/ST, maximum tension are higher than in the OVX group, comparable with the Sham animals which do not demonstrate the situation of hypoestrogenism. According these results it can be suggested that postmenopausal women, with contraindication for hormone replacement, can benefit with the realization of ST, which stimulates the differentiation to bone cells and facilitates the bone formation and reversal of bone loss.