[Effect of size-fractionated thymocytes on the number of hematopoietic stem cells in the bone marrow of sublethally irradiated mice].

A study was of the influence of size-fractionated thymocytes in the density gradient of bovine serum albumin on the number of CFUs in the bone marrow of mice exposed to sublethal irradiation. Subject to separation were thymocytes obtained from intact mice and mice after multiple injections of dexamethasone (DM). Two cell populations were demonstrated during separation of thymocytes from intact mice. Injection of the first cell population brought about a decrease in the number of CFUs in the bone marrow during postradiation recovery, whereas injection of other thymocyte subpopulation resulted in an increase in CFUs. The use of thymocytes obtained from DM treated mice enabled the detection of an increase in bone marrow CFUs, induced by both unfractionated thymocytes and two fractions of thymocytes.