Fig. 3
The functional features of mesenchymal stem cells (MSCs) observed in vitro after culture of Biocoll isolated mononuclear cells (MNCs) with conventional standard plastic adherence methods (left panels) versus FACS-purified and cultured CD13high CD105+ CD45– BM cells (right panels). Panels I a and I b show undifferentiated and unstained MSCs cultured for 24 days (passage 3). Panels II through V display cells which have been induced to differentiate in vitro towards the osteogenic (Panels II and III), adipogenic (Panels IV) and chondrogenic (Panels V) differentiation pathways. Osteogenic differentiation was assessed using alkaline phosphatase (Panel II) and alizarin red S (Panel III) stainings at days +8 and +11, respectively; adipogenesis was determined using the oil red O staining at day +8 (Panel IV), and chondrogenesis was evaluated by toluidine blue staining at day +27 (Panel V). For each staining technique in Panels II–IV, undifferentiated controls counterstained with hematoxylin are also displayed (Panels a and c)