Figure 5: Collagen expression of AFSCs (a, c, and e) and NPSCs (b, d, and f) determined by immunocytochemistry (a)–(f) and analyzed by semiquantification (g). More than 85% of AFSCs expressed collagen type I (a, g), whereas less than 40% of NPSCs were positively stained for collagen type I (b, g). More than 80% of NPSCs and AFSCs expressed collagen type II (c, d, and g). There was no significant difference in the expression of collagen type III for AFSCs (e, g) and NPSCs (f, g). Bars: 100 μm.