Ação da atividade física sobre as propriedades mecânicas dos fêmures e tíbias de ratas osteopênicas

Abstract

We evaluated the mechanical properties, obtained by essays of flexion-compression of femurs and flexion in 3 points of tibiae of adult female ovariectomized rats and exposed to physical activity. To perform this experiment 30 rats divided randomly in three groups were used:Group 1 -Control. Group 2: formed by ovariectomized animals, not submitted to physical activity. Group 3: the animals in this group were trained in a treadmill for 5 consecutive days and then submitted to the ovariectomy, remaining in rest for 24 hours. They were submitted to physical activity for 30 minutes with a velocity of 0,31 m/s, five days a week during 9 weeks.The femurs had their distal portion included in acrilic resinous so that the essay of flexioncompression could be done. And the tibiae were submitted to the flexion essay in 3 points.Based on the results, graphics on the cargo versus deformation, which showed that the femurs of the ovariectomized rats presented a statisticaly significant reduction in its mechanical properties of maximun cargo and maximun deformation. The femurs of the ovariectomized group and submitted to the physical activity presented higher values of maximun cargo and maximun deformation, than the group that was just ovariectomized, however, with no statistical importance. The tibiae did not present significant alterations in any of the mechanical properties studied. The physical activity applied for 30 minutes, 5 days a week during 9 weeks with a velocity of 0,31 m/s was not enought to correct the biomechanical alterations of the bone tissue caused by the ovariectomy.

Effects of swimming associated with risedronate in osteopenic bones: An experimental study with ovariectomized rats

“…After densitometric analysis the same bones were used for the mechanical analysis in the universal testing machine (EMIC ® -10000N), Laboratory of Bioengineering of FMRP-USP, according to protocols used previously (Abrahão et al, 2006;Simões et al, 2008).…”