Interleukin-6(IL-6) is a cytokine with a wide range of biological activities, produced by fibroblasts. T-lymphocytes, endothelial cells and monocytes, play a role in acute-phase inflammatory, and immunologic responses. But it's effect on
hematopoiesis
are not fully understood.
Although megakaryocyte development is a continous process, it has been useful to consider early proliferative and late maturation stage which is stimulated by megakaryocyte-colony stimulating factor and thrombopoietin.
The present study was undertaken to investigate the effect of human recombinant IL-6(rhIL-6) on murine measured by bone marrow granulo-macrophage(GM) and megakaryocyte(Meg) colony formation in liquid culture system, and megakaryocyte ploidy which
was
compared with pokeweed mitogen-stimulated lymphocyte conditioned medium(CM).
@ES The results were obtained as follows:
@EN 1) The total colony number at day 3 and 5 were 6, 667±2,582/mL(mean±1SD). 21,500±11,979/mL in control group(n=12), 23,333±12,910/mL, 51,148±30,974/mL in CM treated group(n=12), and 17,500±2,887/mL, 48,333±6,330/mL in rhIL-6 treated
group(n=8). Total colony count were maximun at day 7 which were 2-3 times higher than total colony count at 3 day in all groups. CM and rhIL-6 had similar stimulating activity on colony formation.
2) Acethylcholinesterase positive megakaryocyte colonies were not found in control group. The ratio of megakaryocyte colony was significantly higher in rhIL-6 group than CM treated group at day 3 and 7.
3) The megakaryocyte colony counts were 2,710±1,038/mL, 7,775±3,570/mL in CM treated group and 3,638±431/mL, 9,930±7,091/mL in rhIL-6 treated group at day 3 and 7 respectively. RhIL-6 had more promoting activity to formation of megakaryocyte
colony
than CM(P<0.05).
4) The change of megakaryocyte ploidy was not found at day 7 culture in control group, but it gradually increased in CM treated group. rhIL-6 promoted a significant increase of ploidy classes, reaching maximum at day 5, and it decreased at day
7.
5) Later addition of rhIL-6 at day 4 showed megakaryocyte ploidy increment, but it show less increment on the total and megakaryocyte colony formation.
These data suggested that rhIL-6 appears to exhibit two distint roles to promote the early colony formation and later maturation of megakaryocyte. So rhIL-6 act as a megakaryocyte-colony stimulating factor (CSF) and potentiator, it is an
important
regulator of hematopoiesis.
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