A biomechanical and spectroscopic study of bone from rats with selenium deficiency and toxicity

Selenium, being an essential mineral in the mammalian diet, is important in providing protection against oxidative damage. Numerous in vitro studies o f selenium compounds reveal a very high correlation between catalytic activ ity of selenium compounds and toxicity. The present study was designed to i nvestigate the effects of dietary selenium on the biomechanical properties of bone. New born rats of both sexes were fed with either a control, or a s elenium- and vitamin E-deficient, or a selenium-excess and vitamin E-adequa te diet. We obtained the stiffness (modulus of elasticity) of bones (femur and tibia) by tensile test for all groups considered. Both the deficient an d the excess groups have decreased biomechanical strength with respect to t he control group. To support our biomechanical results for both experimenta l groups, X-ray diffraction analysis and FTIR spectroscopic study were perf ormed on the femurs and tibiae. The X-ray diffraction analysis showed that the intensities of the peak observed at around 2 theta degrees = 31.820, in the control femur and tibia are stronger than the intensities of the corre sponding peak of two experimental groups. In FTIR spectroscopy, the disappe arance and/or reduction of the intensities of some carbonate bands in the t wo experimental groups indicate that there is a decrease in crystallinity a nd mineral contents which, together with X-ray diffraction analysis, correl ate very well with the biomechanical data.