OBJECTIVETo reconstruct a human bone marrow niche in immunodeficiency mouse (NOD/SCID) so as to provide a model for observing the effect of abnormal BM niche on the occurence and development of leukemia.

METHODSHuman platelet lysate(HPL) was obtained by repeated freezing and thawing of concentrated platelet. Bone marrow-derived mesenchymal stem cells were cultured in α-minimal essential medium (α-MEM) containing 10% HPL or 10% FBS. The morphology, cell phenotype, multilineage differentiation potential in vitro and proliferation capacity between the mesenchymal stem cells cultured with HPL or FBS were compared. The human bone marrow formation capacity of HPL-cultured MSC was observed. The MSC was seeded on β-TCP scaffolds for 12h, then the MSC-coated scaffold were implanted in a subcutaneous pocket on the dorsum of NOD/SCID mice. After 8-12 week, the scaffolds were harvested from the mice, then fixed, paraffin-embedded and stained for HE.

RESULTSWhether cultured in the presence of HPL or FBS, the MSC all displayed a spindle-shaped fibroblast-like morphology; the flow cytometry analysis revealed no obvious differences in cell immunophenotype in this 2 groups; they all have the ability to differentiate towards osteoblasts, adipocytes, and chondrocytes in vitro. However, the mesenchymal stem cells cultivated with HPL-contained medium showed stronger proliferation capacity and higher activity to differentiate towards osteoblasts. Mesenchymal stem cells cultivated with HPL still have in vivo bone-forming capacity.

CONCLUSIONHPL cultured MSC have stronger proliferation capacity and potential of differentiate towards osteoblasts, HPL-cultured MSC also can reconstruct humanized bone marrow niche in murine host.