Skip to main content
. 2015 Dec 31;10(12):e0146124. doi: 10.1371/journal.pone.0146124

Fig 2. Gene expression levels of ALK5 (TGFBR1) and ALK1 (ACVRL1) are not associated with the chondrogenic capacity of human BMSCs.

Fig 2

To induce chondrogenesis, BMSCs (passage 2–4) from adult donors A1 –A5 and fetal donor F1 were pellet-cultured in chondrogenic medium and stimulated with TGFβ. Cartilage-specific gene expression of aggrecan (ACAN) (A) and collagen type IIα1 (COL2A1) (B) was determined in BMSCs cultured for 0, 1, 4, 7 and 21 days using RT-qPCR. Cartilage-specific protein depositions of proteoglycans (C; upper panel) and collagen type II (C; lower panel) were stained in sections of 21 days-cultured pellets. To stain proteoglycans, sections were stained with Safranin O (red/orange) and Fast Green (blue) was used as counterstaining. Collagen type II was stained immunohistochemically (pink) and hematoxylin (purple) was used as counterstaining. Representative images of consecutive pellet sections per donor are shown and the scale bar represents 500 μm. TGFBR1 (D) and ACVRL1 (E) expression levels were measured in BMSC monolayer (day 0) and pellets cultured for 1, 4 and 7 days. Gene expression was normalized to reference gene RPS27a. Data points represent mean ± SD of triplicate BMSC pellets per donor per time point.