Cumulative bone marrow stromal damage caused by X-irradiation and cytosine-arabinoside in leukemic mice.

A study of treated murine acute myeloid leukemia (AML) with an emphasis on the bone marrow stromal function is reported. Leukemia was induced in C57Bl mice through intraperitoneal (i.p.) inoculation of C-1498 myelogenous leukemic cells. The leukemic mice were administered: (1) total body lethal X-irradiation (t.b.i.); (2) two i.p. cytosine-arabinoside (Ara-C) injections followed by X-irradiation. Control mice received similar regimens. Bone marrow of experimental and control mice was processed for stromal cell cultures (SCC) and in vitro engraftment of hematopoietic cells onto the cultures. The results of this study indicate that the bone marrow stromal deficiency which occurs in leukemia is aggravated by Ara-C and irradiation treatments. Moreover, SCC of treated leukemic mice sustain in vitro hematopoiesis only to a limited degree. Stromal deficiency, as possible cause for graft failure in bone marrow transplanted leukemic patients, is discussed.