ROLE OF MICROENVIRONMENTAL DETERIORATION OF THE BONE-MARROW IN THE DEVELOPMENT OF BONE ATROPHY IN MAGNESIUM-SILICATE HYPHEN TREATED RATS

The role of microenvironmental deterioration of the bone narrow in the development of bone atrophy was examined in rats with bone atrophy in duced by magnesium silicate. In the tibial metaphyses, proliferation o f myelocytic elements o haematopoietic tissue was prominent and caused narrowing o sinusoids, increased distance between sinusoids and trabe cular bone and atrophy of trabecular bone. There was a significant cor relation in volume percentage between haematopoietic cells and trabecu lar bone, between haematopoietic cells and sinusoids and between sinus oids and trabecular bone. These results imply that atrophy of trabecul ar bone is related to microenvironmental deterioration of the bone mar row, that is, a decrease in efficiency of exchange of nutrients and wa ste products between sinusoids and trabecular bone due to the prolifer ation of haematopoietic cells and a deficiency of nutrient supply to t he bone marrow due to the narrowing of sinusoids.