OBJECTIVEIn order to investigate whether or not thrombopoietin (TPO) could promote the fibrogenesis of bone marrow stromal cells in absence of megakaryocytes (MKs).

METHODSImproved dexter culture system with various TPO concentrations was used for ex vivo culture of bone marrow stromal cells. Relative proliferation index, the expressions of fibronectin, laminin and type IV collagen, and the systhesis of type III procollagen were detected at different time points during culture process.

RESULTSTPO stimulated the proliferation of bone marrow stromal cells. Relative proliferation index of the stromal cells increased with the TPO concentration increasing, and was not related to the exposure time. The expressions of fibronectin, laminin, and type IV collagen appeared stronger in the TPO groups than those in the control group. But the expressions of these molecules were not dependent upon the culture time. TPO could accelerate the synthesis of type III procollagen in bone marrow stromal cells, and this acceleration was unrelated to the TPO concentration.

CONCLUSIONThese findings suggested that TPO could stimulate the stromal cells with a consequence of increased syntheses and secretions of the extracellular matrix and collagen in absence of MKs. In other words, TPO could promote the fibrogenesis of bone marrow stromal cells without the existence of MKs.