Fig. 4.

Sprifermin ((rhFGF18); (EMD Serono Inc., Rockland MA, subsidiary of Merck KGaA, Germany)] enables proliferation of chondrocytes producing a hyaline cartilage matrix. The histology results correspond well to the biochemical and gene expression results. In the 3D constructs cultured in the absence of sprifermin, no Safranin O or type II collagen staining was visible, but the constructs were positive for type I collagen, illustrating that these chondrocytes were not able to produce a cartilage-like extracellular matrix. In the presence of both permanent and 1 day/week sprifermin, a Safranin O and type II collagen-positive matrix was observed, while type I collagen staining was less intense in comparison to the control. Gigout A, Guehring H, Froemel D, et al. Sprifermin (rhFGF18) enables proliferation of chondrocytes producing a hyaline cartilage matrix. Osteoarthritis Cartilage. 2017;25(11):1858–1867. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited