DECREASE OF THE CRYSTALLINITY OF BONE-MINERAL IN OSTEOPETROTIC RATS

The membraneous and long bones of three groups of Fatty Orl-op rats i.e. phenotypically normal animals, osteopetrotic (op/op) mutants, and op/op mutants cured by transplantation of normal bone marrow were compared with regard to the amount and crystallinity of inorganic constituents. The electron spin resonance spectrometry based on measurements of stable paramagnetic centers induced by ionizing radiation in the crystalline lattice of bone hydroxyapatite was used for evaluation of crystallinity of bone mineral. The crystallinity coefficient defined as the ratio of spin concentration of these centers to the total ash content of the sample was calculated. In compact bone of op/op mutants a small increase (about 4%) of mineral content was observed, while the crystallinity of mineral was significantly lower, reaching about 80% of the value found in the phenotypically normal littermates. In op/op mutants cured by transplantation of normal bone marrow the trend for normalization was found. These observations demonstrate the possibility that the crystallinity of bone mineral can be used as a parameter in the diagnosis and monitoring of the therapy in osteopetrosis. © 1979.