| Abstract: |
Megakaryopoiesis orthrombopoiesisis a complex multi-step processthat begins with the commitment of a pluripotenthaematopoieticstem cells toa differentiation pathway ( Ellis, et al., 1995 ) .The committed megakaryocyte progenitor cell undergoes proliferationand subsequent differentiation into a mature megkarycyte which ultimatelyreleases platelets into the circulation ( Mazur, 1987 ).Thrombopoiesis is regulated by a immoral mechanism in which the rateof platelet production responds to the number or mass of circulating platelets( Odell 1974 and Ebbe 1976 ).Several cytokines such as interleukin-3, interLukin-6, interleukin-11,leukaemia inhibitory factor and granulocyte-macrophage colony stimulatingfactors have shown to promotemegakaryocytopoiesisat different stages ofdeveloymentand platelet production ( Yang, et al., 1986 ;Ikebuchi,et al.,1987; Qiesenbery, et al., 1985; Bruno, et al., 1989; Ishibasli, et al.,1989; Hill, et al., 1990; Teramura, et al., 1992; Burstein, et al., 1992;Metcalf, et al., 1991 and Wong, et al., 1985 ).Interleukin-6 acts on mature megakaryocytes by its effects onmegakaryocyte ploidy and size ,leukaemia inhibitory factor increasesmegakaryocyte frequency and circulating platelet levels and interleukin-1 1increases platelet levels , megakaryocyte ploidy and number ofmegakaryocyte progenitor cells ( Neben, et al., 1993 ).Thrombocytopenia is defined as any of the bleeding disorders thatresults from a lack of functional platelets
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