Figure 2
From: Tendon proper- and peritenon-derived progenitor cells have unique tenogenic properties
Progenitor-derived matrix assembly is ultrastructurally similar to that of embryonic tendon. Ultrastructure was examined by cross-sectional images. In both the E15 to E17 Achilles tendon (A) and the progenitor constructs (B-E), collagen fibril synthesis and fiber assembly by cell processes are evident with fibers labeled with black dashed-line ovals (A-E). Panels: Embryonic Achilles tendon (A), tendon proper (TP)-derived progenitor-seeded construct (B), peritenon (PERI)-derived progenitor-seeded construct (C),TP-derived progenitor-seeded construct supplemented with GDF5 (D), peritenon (PERI)-derived progenitor-seeded construct supplemented with GDF5 (E). ETC: embryonic tendon cell; TP: tendon proper-derived progenitor; PP: peritenon-derived progenitor (Bar: 1 μm). E, embryonic day; GDF5, growth differentiation factor 5.