Effects of RUNX2 knock-down in human C3 MSCs differentiation. (a) Oil red-O stained cultures, showing multiple areas of red lipid staining in shRUNX2 treated cells (as indicated by black arrowspointing to intracellular lipid droplets formation). (i, ii) Details of positive oil red-O-staining in treated cells, as seen in transmitted light. No droplets for adipogenic differentiation were observed in control mock treated-cells. Scale bar = 120 µm, 40 µm, 20 µm, 10 µm. (b) Strong deposition of mineralized matrix was observed in mock control cells by Von Kossa's stain. Weak mineralization detected by Von Kossa method in shRUNX2 transduced cells. Scale bar = 120 µm.