Studies of the humoral factors produced by layered chondrocyte sheets.

The authors aimed to repair and regenerate articular cartilage with layered chondrocyte sheets, produced using temperature-responsive culture dishes. The purpose of this study was to investigate the humoral factors produced by layered chondrocyte sheets. Articular chondrocytes and synovial cells were harvested during total knee arthroplasty. After co-culture, the samples were divided into three groups: a monolayer, 7 day culture sheet group (group M); a triple-layered, 7 day culture sheet group (group L); and a monolayer culture group with a cell count identical to that of group L (group C). The secretion of collagen type 1 (COL1), collagen type 2 (COL2), matrix metalloproteinase-13 (MMP13), transforming growth factor-β (TGFβ), melanoma inhibitory activity (MIA) and prostaglandin E2 (PGE2) were measured by enzyme-linked immunosorbent assay (ELISA). Layered chondrocyte sheets produced the most humoral factors. PGE2 expression declined over time in group C but was significantly higher in groups M and L. TGFβ expression was low in group C but was significantly higher in groups M and L (p<0.05). Our results suggest that the humoral factors produced by layered chondrocyte sheets may contribute to cartilaginous tissue repair and regeneration.