Efficiency of Human Epiphyseal Chondrocytes with Differential Replication Numbers for Cellular Therapy Products

Figure 5

Long-term observation at the P1 (PDL 10) cell-implanted sites. P1 (HEC #9) cell-implanted sites were analyzed at 25 weeks (a–f) and 41 weeks (g–l). Macroscopic examination of the P1 (PDL 10) cell-nodules (86 mg in weight) at 25 weeks showed smooth and semitranslucent surface with irregular light reddish portion (a). Microscopic examination showed cartilage with thin perichondrium (b). The cartilage was composed of small chondrocytes with round or spindle nuclei and lacunae in the extracellular matrix (c). Matrix of the cartilage (d) and perichondrium (e) was positive for COL II and COL I, respectively. CD34-positive vessels were not detected (f). Macroscopic examination of the P1 cell-nodules (69 mg in weight) at 41 weeks showed smooth and whitish surface with focal yellowish portion (g). Microscopic examination revealed focal enchondral ossification in the cartilage (h) and bone formation with early marrow cavity (i). Cartilage with enchondral ossification was positive for COL II (j), and perichondrium, osteoid, and new bone (k) were positive for COL I. CD34-positive vessels were expanded in the early bone marrow cavity (l).