Structural forms of fluorides in bone tissue of animals under chronic fluoride intoxication

High-resolution solid-state F-19 NMR method has been used to examine the chemical structural forms of fluorine introduced into the bone tissue of experimental animals (Vistar rats) exposed to 30 day fluoride inhalation. It is shown that in the bone tissue three structural forms of fluorides are deposited: a solid phase of F-apatite and mobile nanoparticles of CaF2 and MgF2 (or KMgF3) with the ratio of fluorine concentration in these three forms similar to 2:2:1. During the following 30 day rehabilitation this ratio remains constant, the total fluorine content in the bone tissue decreases similar to 3 times and the F-apatite phase transforms into disordered (F, OH)-apatite. A protective effect of the zeolitic enterosorbent (klinoptilolite) on fluorine binding in the intoxication process was found, as well as the promotional effect of this enterosorbent on fluorine excretion during the postfluoride rehabilitation.