WJCs characterization. Light microscopic micrographs of WJ-MSCs in monolayer at the 4th(A) and the 12th(B) culture passages. In monolayer culture, cells assumed a polymorphic, fibroblast-like morphology, which was maintained throughout the time of culture (scale bar 40 μm). Growth characterization of WJ-MSCs during the in vitro expansion (4th and 12th passage) measured by cell count (C) and by the BrdU incorporation assay, allowing the doubling time evaluation (D). The ability of WJ-MSCs to differentiate into the adipogenic lineage at the 4th(E) and the 12th(F) culture passages was evidenced by the intracellular accumulation of neutral lipid vacuoles (red oil staining) (scale bar 20 μm). Osteogenic differentiation at the 4th(G) and the 12th(H) culture passages was indicated by the increase in alkaline phosphatase reaction (scale bar 80 μm). Light microscopic micrographs A, B, E, F, G and H are representative of five separate biological samples.