Previous studies have demonstrated that nerve cells differentiated from adipose-derived stro-mal cells after chemical induction have reduced viability;however, the underlying mechanisms remained unclear. In this study, we induced the differentiation of adult adipose-derived stromal cells into astrocytes using chemical induction. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetra-zolium bromide assay and flow cytometry showed that, with increasing induction time, the apoptotic rate gradually increased, and the number of living cells gradually decreased. Im-munohistochemical staining demonstrated that the number of glial fibrillary acidic protein-, caspase-3- and caspase-9-positive cells gradually increased with increasing induction time. Transmission electron microscopy revealed typical signs of apoptosis after differentiation. Taken together, our results indicate that caspase-dependent apoptosis is an obstacle to the differentia-tion of adipose-derived stromal cells into astrocytes. Inhibiting apoptosis may be an important strategy for increasing the efifciency of induction.

β-mercaptoethanol can induce adipose-derived stromal cells to rapidly and efficiently differentiate into neurons in vitro. However, because of the short survival time of the differentiated cells, clinical applications for this technique are limited. As such, we examined apoptosis of neurons differentiated from adipose-derived stromal cells induced with β-mercaptoethanol in vitro using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling and transmission electron microscopy. The results revealed that the number of surviving cells decreased and apoptosis rate increased as induction time extended. Taken together, these results suggest that apoptosis occurring in the process of adipose-derived stromal cells differentiating into neurons is the main cause of cell death. However, the mechanism underlying cellular apoptosis should be researched further to develop methods of controlling apoptosis for clinical applications.

The quantity and survival time of astrocytes, which were differentiated from adult adipose-derived stromal cells after exposure to an inducer containing 3-isobutyl-1-methylxanthine, have thus far been unsatisfactory. The present study investigated the growth and differentiation characteristics of induced astrocytes by observing their growth curves. After induction for 48 hours with an inducer containing 0.5% ethanol, some adult adult adipose-derived stromal cells displayed typical astrocytic morphology. The cell quantity gradually decreased with prolonged induction time. Nestin, glial fibrillary acidic protein, and S-100 expression reached peak levels at 14 days, but neuron-specific enolase was not expressed. These results suggest that the induced astrocytes reached their peak at 14 days. Further optimization of the culture environment may yield mature astrocytes with normal functions, in greater quantity, and prolonged survival time.