FIG. 6.

UC-MSCs promote granulocytic differentiation of NB4 cells by way of secreting IL-6. (A) NB4 cells were treated by UC-MSCs or/and 10 nM ATRA for 72 h, and IL-6 in supernatants was quantified by enzyme-linked immunosorbent assay. It is not detected when NB4 was cultured without UC-MSC treatment. (B) The CD11b expression level was determined by flow cytometry after 48 h incubation with or without the addition of the IL-6Ra neutralizing antibody. (C) CD11b positivity was assessed by flow cytometry after 48 h culture with or without administration of exogenous recombinant human IL-6 at a concentration of 50 ng/mL (a). The morphological change under a microscope was illustrated by Wright–Giemsa staining after 72 h culture (b). Original magnification: ×100. (D) IL-6 mRNA in UC-MSCs and NB4 cells after 24 h culture was quantified by real-time polymerase chain reaction, respectively (a). Photographed image of electrophoresis of PCR products (b). Indications: M0 stands for UC-MSCs cultured alone; M1 stands for UC-MSCs cultured with NB4; M2 stands for UC-MSCs cultured with NB4 plus ATRA; N0 stands for NB4 cultured alone; N1 stands for NB4 treated with UC-MSCs; N2 stands for NB4 treated with ATRA; N3 stands for NB4 treated with UC-MSCs plus ATRA. Experiments are repeated at least three times. **p<0.01.