On the Development of Slowly-turning-over Cell Types in Neonatal Rat Bone Marrow (Studies Utilizing the Complete Tritiated Thymidine Labeling Method Complemented by C-14 Thymidine Administration)

Abstract

1. The continuous H3-thymidine (H3-TdR) intravenous infusion of rats from day 9 of pregnancy until term results in the labeling of every single cell nucleus in the body of the offspring. Completely labeled newborn rats were sacrificed at serial intervals after birth. This provided the opportunity to follow the labeling pattern of all bone marrow cells during the development of this organ. Cytokinetically three types of cell renewal systems could be found: one type showed a rapid turnover losing all H3-TdR within 6 days, e.g., erythropoietic and myelopoietic cells. Another lost most of its labeling throughout the same time except a small but significant fraction (bone marrow lymphocytes). The third retained a high fraction of labeled cells with a high labeling intensity for weeks and months (reticular cells and endothelial cells). 2. A continuation of H3-TdR administration of 100 per cent labeled newborn rats throughout the first three weeks of neonatal life resulted cytokinetically in the same three different cell types. However, a larger fraction of reticular and endothelial cells as well as bone marrow lymphocytes remained labeled weeks and months after the last injection as compared with the first group of 100 per cent labeled animals. 3. An administration of C14-TdR to 100 per cent labeled newborn animals throughout the first 6 days after birth Showed that 30 to 40 per cent of the "resting" bone marrow cells have turned into a resting state before or at least at the time of birth. Forty per cent of these cells still had some proliferative capacity during the first 6 days of life. Twenty per cent showed in the first days after birth a rapid turnover whereas later on they acquired their final cytokinetic state. The possible influence of radiation toxicity on the time of establishment of resting cells is discussed. This approach appears of use to study the functional properties of resting bone marrow cell types in regenerative processes and the cellular origin in the bone marrow.

Lymphocyte Populations in Mouse Bone Marrow: Quantitative Kinetic Studies in Young, Pubertal and Adult C3h Mice

“…This population of marrow small lymphocytes is itself probably heterogeneous both functionally and kinetically. In young rats, following prenatal and neonatal exposure to 3H-thymidine, Haas et al (1969) have described a persisting population of small lymphocytes within the marrow. These cells showed changes during marrow stimulation suggesting a resting stem cell function (Haas, Bohne & Fliedner, 1971).…”

Concise Review: Quiescence in Adult Stem Cells: Biological Significance and Relevance to Tissue Regeneration

“…Early studies of bone regeneration identified the presence of nonhematopoietic, label‐retaining cells within bone marrow, suggesting the presence of quiescent MSCs capable of responding to bone injury and contributing to bone regeneration. For example, label‐retaining MSCs were detected within bone marrow after injecting 3 H‐TdR label in rat, from day 9 of pregnancy till birth . In addition, label‐retaining MSCs within murine bone marrow could be enriched by 5‐FU treatment .…”

Growth of Mycobacterium lepraemurinum in the mouse bone marrow: an ultrastructural study

“…The marrow macrophage is a differentiated cell of the mononuclear phagocyte series (13) that does not divide (6,7), so the observed rapid multiplication of M. lepraemurium does not seem to be connected with the multiplication of the host cell. Possibly some breakdown product of the cell debris of the marrow provides a necessary nutrient.…”

“…Mice of highly susceptible strains (e.g., CBA, BALB/c) infected intravenously with 10" Mycobacterium lepraemurium develop a progressive disease that kills them in 5 to 6 months. The overall generation time of the bacteria in such animals is 7 to 10 days (17), but Brown and Krenzien (2; Int. J. Lepr.…”