An integrated model for tissue engineered cartilage repair in vitro

BACKGROUND: With the development of tissue engineering, autologous chondrocyte implantation is often used to repair cartilage defects. And poor integration is one of the common reasons that lead to failure repairing. Many models in vitro are used for related studies. OBJECTIVE: To develop an interface integrated model of tissue engineered cartilage repair in vitro and to evaluate the effect. METHODS: Cartilage integration model in vitro was established in pigs. Totally 21 cartilaginous rings were obtained and divided into agarose gel group (n=18) and control group (n=3). In agarose gel group, cartilage rings were covered with agarose gel. Chondrocytes were separated and implanted into the ring. The leakage of cells around the cartilage rings was observed. The sections were stained for histological observation at 1, 2, 4 weeks. The average area of neochondrocytes was measured and compared. RESULTS AND CONCLUSION: The results from the control group were not processed, because there was no chondrocyte aggregate formation in the center of the explant ring due to earlier chondrocyte leakage outside the explant. While no chondrocytes were found outside the explant ring in the agarose gel group. Tissue sections of the agarose gel group were stained by hematoxylin and eosin, alcian blue, Safranin-O and collagen type II immunohistochemistry at 1, 2, 4 weeks. Neochondrocytes proliferated within cartilage ring, and producedextracellular matrix. After 2 weeks of incubation, these inserted chondrocytes were significantly increased. There was no statistically significant increment between 2 weeks and 4 weeks (P > 0.05), although the area was further increased by 4 weeks. This model provides a convenient simulation of the cartilage integration process in vitro and has a potential application in studies of cartilage integration and cartilage tissue engineering.