Effect of Induction Time on the Proliferation and Differentiation of Induced Schwann-Like Cells from Adipose-Derived Stem Cells

To compare how different induction time takes effect on the proliferation and secretion ability of adipose-derived stem cell (ADSC)-induced Schwann-like cells (iSCs), ADSCs were isolated from healthy adult female rats. Flow cytometry (FCM) was performed to detect the ADSC-positive markers CD29, CD44, and CD90 and the negative marker CD45. iSC induction medium was used to culture the ADSCs. S-100, GFAP, MBP, and P75 were detected by immunofluorescence staining to identify iSC differentiation. Cell morphological changes were observed by an inverted microscope after induction. An MTS assay was used to evaluate the cell proliferation ability. Western blot analyses of caspase-3/cleaved caspase-3 and FCM were applied to assess cell apoptosis. Co-culture system of PC12 and ADSCs or iSCs was established to analyse the biological function of iSCs. Among the examined proteins, S-100, GFAP, MBP, and P75 were expressed in iSCs. After day 7, the cell proliferation rate was significantly lower than that before induction, and on day 19, the proliferation rate of iSCs was lower than 50% of the proliferation rate before induction (OD value = 0.016 +/- 0.003 vs. 0.400 +/- 0.004, p < 0.01). Starting from day 19, P21, P53, Apoj, S100, Gdnf, and Mbp all consistently showed a trend toward increased expression. Secretion of NGF, MBP, and BDNF was more enhanced at 19 days than that at 7 days. In co-culture system, the induction effect of iSCs was more pronounced at 19 days than that at 7 days, and the difference was statistically significant (55.40 +/- 4.50 mum vs 37.15 +/- 3.75 mum, p < 0.01). In conclusion, the proliferation ability of ADSC-derived iSCs was negatively correlated with the induction time, while the expression of SC marker proteins was positively correlated. Therefore, iSCs are suitable for use at 19 days after induction.