Expression of nestin (A), GFAP (B) and neurofilament (C) in undifferentiated and differentiated BMSC. Untreated cells were labeled for nestin (A1), whose expression decreased with treatment 1 (A2,3) but persisted after treatment 2 (A4). GFAP immunoreactivity was negative in untreated cells (B1), but after 5 (B2) and 24 hours (B3) of treatment 1 some cells were GFAP positive. Treatment 2 determined strong GFAP immunostaining after 7 days (B4). Immunoreactivity for neurofilaments, totally absent in untreated BMSC (C1), was present in some cell bodies and processes after treatment 1 (C2,3; higher magnification in C3 insert) and treatment 2 (C4). Cells were also stained with Hoechst dye 33258. Bar: 40 μm. Insert bar: 10 μm.