Fig. 5

Osteopontin (OPN) promoted neurogenesis in vitro. a Neural stem cells (NSC) were allowed to differentiate for 7 days (d) after mitogen withdrawal, yielding all three cell fates: neurons (above, green), astrocytes (middle, red), and oligodendrocytes (below, green; scale bars represents 50 μm). b Constant exposure of NSC cultures to OPN at 6.25 μg/ml during differentiation led to increased neurogenesis, while other cell fates were slightly reduced, correspondently, albeit to a non-significant extent (values displayed as means ± SEM; **p < 0.01). c NSC were allowed to differentiate for 7, 10, and 14 days after mitogen withdrawal in the presence or absence of OPN at 6.25 μg/ml; the number of undifferentiated cells was subsequently assessed by staining against SRY (sex determining region Y) box 2 (SOX2). During that period, the number of undifferentiated cells continuously declined, regardless of the presence of OPN (values displayed as means ± SEM). d Generation of TuJ1-positive neurons (green) during differentiation was increased by OPN treatment (lower row) as compared to control (upper row) at days 7, 10, and 14 after mitogen withdrawal. During that period, the axon length grew notably and neurons began to form networks; both observations were more pronounced in OPN-treated cells. By day 14, mature MAP2⁺-positive neurons had formed (right column; scale bars represent 100 μm). e NSC were allowed to differentiate 10 and 14 days after mitogen withdrawal in the presence or absence of OPN at 6.25 μg/ml, and then their morphology was analyzed. Between day 10 and day 14 after mitogen withdrawal, NSC differentiation further proceeded, the neurons formed long processes and network-like formations. This effect was particularly pronounced in the OPN-treated cells (scale bars represent 100 μm)