HISTOMORPHOMETRIC ANALYSIS OF HETEROTOPIC BONE FORMED BY STROMAL-OSTEOGENIC SUBPOPULATIONS

MBA-15.4 and MBA-15.6 cell lines are marrow stromal clonal subpopulati ons and represent various stages of differentiation of the osteoblasti c family. These cells vary in terms of morphology, proliferation rate, synthesis of matrix proteins as collagen and noncollagenous proteins, and by their responses to hormones and growth factors. Their differen tial properties directly reflect the clonal cells' ability to form bon e in vivo. When the cells were transplanted at an ectopic site, under the kidney capsule, MBA-15.4 line formed small foci of bone whereas MB A-15.6 cell line formed massive woven bone during the same period of t ime. In this study, we focused on the histomorphometric analysis of ec topic ossicles formed by the clonal cell lines. Assessments of bone ma ss changes involved measurements of cellular components, osteoid, and formation of primary bone. The bony tissue formed was condensed, no he mopoiesis was noted, and the ossicle was not remodeled. The histology studies were used for quantitative analysis of the ossicle formation a nd describe the dynamics of ossicles formed by the individual cell typ es.