Hematologic effects of stem cell factor in vivo and in vitro in rodents
TR Ulich, J del Castillo, ES Yi, S Yin, I McNiece, YP Yung and KM Zsebo
Department of Pathology, University of California Irvine Medical School
92717.
Recombinant rat stem cell factor (rrSCF) administered to rats as a single
intravenous injection causes a dose-dependent neutrophilia and
lymphocytosis as well as the appearance of immature myeloid cells and
occasional blast cells in the circulation. Neutrophilia begins at 2 hours,
peaks at 4 to 6 hours, and subsides between 12 and 24 hours. Lymphocytosis
occurs at 0.5 hours and has subsided by 2 hours. rrSCF- induced
neutrophilia and lymphocytosis are abrogated by boiling, demonstrating that
endotoxin-contamination of the rrSCF preparation is not responsible for the
observed hematologic effects. The bone marrow at 6 hours after injection of
rrSCF shows a left-shifted myeloid and erythroid hyperplasia as evidenced
by significant increases in the absolute numbers of morphologically
recognizable early myeloid and erythroid precursors. A concurrent decrease
in the absolute numbers of mature marrow neutrophils is noted, suggesting
that the release of marrow neutrophils contributes to the peripheral
neutrophilia. After 2 weeks of daily injections of rrSCF, bone marrow
smears demonstrate a remarkable mast cell hyperplasia accompanied by a
decrease in total marrow cellularity and by a striking erythroid and
lymphoid hypoplasia. rrSCF also causes mast cells to appear in the
circulation and causes a systemic increase in embryonic connective
tissue-type, but not mucosal- type, mast cells. In vitro long-term culture
of lineage-depleted mouse bone marrow cells with rrSCF results in an almost
pure outgrowth of mast cells.
Volume 78,
Issue 3,
pp. 645-650,
08/01/1991
Copyright © 1991 by The American Society of Hematology
