Fig. 1

Effect of culture duration on surface marker expression. a Flow cytometric analysis of CD45 expression by cBM cultures. Histograms show CD45 staining at the indicated passage numbers with the percent positive cells in each panel (white, solid line, CD45; tinted, dashed line, isotype control). b Summary of CD45 distribution at different passages. Values represent mean ± SD of at least three experiments. Significance testing was done using one-way ANOVA. *p <0.05, **p <0.01. c Cytogram display of FSC-A versus SSC-A for different CD45 subpopulations (grey, CD45⁻; black, CD45⁺). CD45⁺ cells have lower SSC signals than CD45⁻ cells. d Human MSC marker expression of gated CD45⁻ cells from cBM during in-vitro passaging. Values represent mean ± SD of at least three experiments. Significance testing was done between passage 1 and passage 3 for CD73 (#), CD90 and CD105 (*). #/*p <0.05, Student’s t test. e Cytogram displaying the distribution of CD73 versus CD90 over passaging. Quadrants were placed based upon negative control samples in the lower left quadrant. The percent positive cells in each quadrant are shown. f Pie-chart representation of the distribution for CD73 versus CD90 of freshly-isolated cBM and fBM. Lower right panel shows the colour codes used to define the four subpopulations expressing CD73 or CD90. g Phenotypic evolution of mMSC markers: Sca-1 (left), CD44 (middle) and CD29 (right), in Sca-1 defined subpopulations in freshly-isolated cBM and fBM and cultured cBM preparations. Cultured cBM (lower panels) has been expanded in-vitro for two passages. cBM compact bone marrow, fBM flushed bone marrow