Bone demineralization mechanisms at level of free radicals and nanoscale subsystems of bone tissue.

Influence of simulated microgravity on characteristics of rat bones was investigated by electron paramagnetic resonance (EPR). For simulation of microgravity condition the hanging of animal by tail was used. The main measurements were performed for diaphysis of femoral bones. The quantity of native radicals Rn, localized in an organic matrix, and carbonate radicals CO2-, localized on a surface of bioapatite nanocrystals, were determined. The decrease of CO2- radical quantity in bones of experimental animals have shown, that due to simulation of microgravity the decrease of "collagen-nanocrystals" interaction takes place. It is shown that the EPR method open possibilities to receive the unique information about bone demineralization processes at level of free radicals and nanoscale subsystems of bone tissue.