HB-EGF prevents MSC differentiation induced by specific media. Confluent MSCs were cultured for 14 days in flasks and culture slides with no differentiation medium (No DM) or in the presence of adipogenic (AM), osteogenic (OM), or chondrogenic (CM) medium, without and with 50 ng/mL HB-EGF; then cells were stained with Oil-red-O, von Kossa, and toluidine blue methods, respectively, to assess MSC differentiation. MSCs cultured in the presence of HB-EGF did not show any specific differentiation. The figure shows a representative case of 3 different experiments. In each box, left images show unstained cells and right images show cells stained with specific dyes. Images were visualized through an Olympus BX50 microscopic equipped with UPlan FL 100×/1.30 oil objective lens (Olympus, Tokyo, Japan). Acquisition was performed with Nikon ACT-1 2.20 software (Nikon, Tokyo, Japan); processing, with Adobe Photoshop 7.0 (Adobe, San Jose, CA).