Mesenchymal Stem Cells in Oriented PLGA/ACECM Composite Scaffolds Enhance Structure-Specific Regeneration of Hyaline Cartilage in a Rabbit Model

Figure 4

H.E. staining of repaired cartilage at 12 and 24 weeks postimplantation. (a) and (b) At 12 weeks postoperation, the defect area in the untreated group was partially filled with fibrotic tissue. No evident cartilage or subchondral bone regeneration was evident. Moreover, no regeneration was evident at 24 weeks; only fibrous tissue was present. (c) and (d) At 12 weeks postoperation, the defect region was filled with repaired tissue and the boundary exhibited continuous integration with healthy cartilage. The repaired cartilage was clearly thinner than native cartilage. At 24 weeks postimplantation, no further obvious cartilage regeneration was apparent; however, subchondral bone regeneration had progressed further. (e) and (f) At 12 weeks postoperation in the cell-loaded scaffold group, the cartilage defect was filled with regenerated cartilage and subchondral bone and the boundary exhibited continuous integration with healthy cartilage. The thickness of the repaired cartilage was close to that of native cartilage. At 24 weeks postimplantation, cartilage and subchondral bone regeneration were further enhanced and the tissues were similar to native tissues (bars: 50 μm).