ABSTRACT
Stromal bone marrow mechanocytes responsible for microenvironment transfer during heterotopic transplantation of hemopoietic tissue from fibroblast clones in monolayer cultures. Fibroblast colony forming cells (FCFC) are readily released from tissue structures together with hemopoietic elements and are contained in bone marrow cell suspension at a concentration of 1 x 10(-5)-10 x 10(-5). Pretreatment with trypsin of bone marrow fragments increases the content of FCFC in bone marrow cell suspension. Trypsin releases from the bone marrow and additional fraction of FCFC (trypsin-dependent FCFC), which are more strongly bound to tissue structures and are likely to be injured in the course of routine suspension of hemopoietic tissue fragments. The ratio of the number of trypsin-independent and trypsin-dependent FCFC is approximately 1 : 10.
Subject(s)
Bone Marrow/drug effects , Fibroblasts , Trypsin/pharmacology , Animals , Bone Marrow Cells , Clone Cells , Colony-Forming Units Assay , Cytological Techniques , Guinea Pigs , Hematopoietic Stem Cells , Hybridization, Genetic , Mice , Mice, Inbred C57BL , Mice, Inbred CBAABSTRACT
The possibility of the formation of a new bone marrow organ from the initially isolated bone marrow cells has been proved for the first time. Suspensions of the bone marrow cells (5 x 10(6)) placed on millipore filters were grafted under the renal capsule in mice. As a result, the bone formed and the medullary cavity developed which was populated by hemopo etc cells. These processes were closely followed during 9 weeks. To compare the sizes of hemopoietic territories formed by grafting of different bone marrow fragments, the number of bone marrow cells in the heterotopic bone marrow was estimated. The bone marrow organs formed under the renal capsule after grafting bone marrow from the whole femur or its half contained practically the same number of hemopoietic cells. It was also true for the subcutaneous transplants of bone cylinders of the same size but with different amount of bone marrow. Hence it follows that the amount of hemopoietic territory grafted depends to a great extent on the transplant form and, therefore, does not reflect the number of initially grafted microenvironment-forming cells.
Subject(s)
Bone Marrow Transplantation , Hematopoiesis , Animals , Bone Marrow Transplantation/physiology , Kidney , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Micropore Filters , Time Factors , Transplantation, IsogeneicSubject(s)
Bone Marrow/radiation effects , Radiation Tolerance , Animals , Cell Survival/radiation effects , Cells, Cultured , Colony-Forming Units Assay , Fibroblasts/radiation effects , Guinea Pigs , In Vitro Techniques , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Radiation Chimera , Time FactorsABSTRACT
The content of clonogenic stromal precursors in the femoral bone marrow, spleen and the thymus of guinea pigs of different age was studied by the in vitro colony assay method (monolayer cultivation of hemopoietic and lymphoid tissue). The concentration and the total amount of the stromal precursor cells was shown to be age-dependent. In the femoral bone marrow and in the spleen the amount of fibroblast precursors was maximal by the age of two months; then, with ageing, it remained at the former level in the spleen, but decreased essentially in the bone marrow. The number of stromal precursors was rather constant in the thymus during the period of its active functional activity, but these cells were absent in the thymus of old animals.
