HETEROTOPIC IMPLANTATION OF MOUSE BONE-MARROW CELLS - AN IN-VIVO MODEL ALLOWING ANALYSIS OF MINERAL PHASES DURING MINERALIZATION PROCESSES

Heterotopic calcification induced after implantation of bone-marrow ce lls under the murine kidney capsule was used to study the mineral phas es occurring during the mineralization process. Ossicles mere found to contain numerous osteoblastic cells that produced an organic matrix c losely associated with active hematopoietic tissue. During implantatio n of bone marrow; needle-shaped microcrystals were progressively depos ited on collagen fibers, The mineral formed in the heterotopic calcifi cation consisted mainly of calcium phosphate, The distribution and den sity of the microcrystals were heterogeneous after 6 weeks of implanta tion but became homogeneous and well-crystallized after 10 weeks. The Fourier transform infrared microspectroscopy provided important spatia l data on the nature of the mineral formed and the changes in the mine ral environment. Similarities were noted between young bone (bone call us) and 6-week heterotopic ossicles, and between adult bone and 10- or 12-week heterotopic ossicles, The study demonstrated that murine hete rotopic calcification under the renal capsule can be a very useful mod el for studying bone apatite formation during the mineralization proce ss.