Chondrocyte Cell-Sheet Transplantation for Treating Monoiodoacetate-Induced Arthritis in Rats

Engineered cell sheets that are fabricated by using temperature-responsive culture dishes are now available in the clinical setting. Engineered chondrocyte cell sheets are used in clinical trials for treating focal articular cartilage defects. However, the efficacy of engineered chondrocyte cell sheets for treating diffusely degenerated articular cartilage remains unknown. In the present study, we assessed the utility of engineered chondrocyte cell sheets for treating diffusely degenerated articular cartilage in a monoiodoacetate (MIA)-induced arthritis animal model. At 1 and 3 weeks after intra-articular MIA injection into rat knees (1 w-MIA/3 w-MIA model), the degenerated cartilage at load-bearing area sized 1 × 3 mm was removed. Rats in each group were divided into three subgroups: Removal (R) group as control, Removal + Drilling (RD) group in which cartilage was removed followed by subchondral drilling, and Removal + Drilling + Sheet transplantation (RDS) group in which the removed cartilage area was covered with a 2 × 4 mm size of triple-layered chondrocyte cell sheet. In the histological assessment, the score of the RDS group in each model was significantly better than that of R and RD groups at 4 and 12 weeks, respectively, after the surgery. Our results demonstrated that the transplanted chondrocyte cell sheets improved cartilage repair even under such severe conditions as diffusely degenerated articular cartilage. Chondrocyte cell sheets appear to be useful as a treatment option for MIA-induced arthritis models.