Research Paper Volume 13, Issue 8 pp 11433—11454

Figure 1. Dedifferentiation of human hyaline chondrocytes occurred during passage culture in vitro. (A) Morphological observations of passage 1 (P1) and P5 chondrocytes. (B) Real-time quantitative PCR (real-time qPCR) results for COL1A1 (alpha-1 type I collagen), COL2A1, and SOX9 expression in P1 and P5 chondrocytes. GAPDH (glyceraldehyde-3-phosphate dehydrogenase) was used as the internal reference. Data are represented as means ± standard deviation (n = 3). (C, D) Western blot analysis for COL1, COL2, and SOX-9 levels in P1 and P5 chondrocytes. β-actin was used as the internal reference. (E–G) Immunofluorescence staining of COL1, COL2, and SOX-9. P1 and P5 chondrocytes were stained with anti-COL2, anti-COL1, anti-SOX-9, and Hoechst 33342. *P < 0.05, **P < 0.01, ***P < 0.001. Scale bar, 100μm.