Figure 5

GDF5 supplementation causes improved expression matrix assembly genes in peritenon progenitors seeded in constructs. After r-mGDF5 supplementation, expression levels for the tendon markers Scx (A) and Tnmd (B) and the vascular marker Emcn (C) still differed. GDF supplementation led to improved expression of matrix assembly genes for peritenon progenitors seeded in tendon constructs - comparing PERI + versus TP at Day 7 (early) and Day 45 (late). Bolstered expression is noted for SLRPs Bgn (D) and early for Dcn (E), for FACIT collagens Col12a1 (F) and Col14a1 (G), and for fibril-forming collagens Col1a1 (H), Col3a1 (I) and Col5a1 (J). Expression of Col11a1 (K) is still greater for tendon proper-derived progenitors. (Biological replicates, n = 5 to 8; Mann–Whitney-Wilcoxon test – P <0.01, *; P <0.05, #; fold changes and statistical significance further reported in Table 3 and expanded results are reported in Additional file 1: Figure S1). GDF5, growth differentiation factor 5; PERI, peritenon-derived progenitors; SLRP, small leucine-rich proteoglycans; TP, tendon proper-derived progenitors.