ABSTRACT
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. Total y 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 col agen type II immunohistochemistry at 1, 2, 4 weeks. Neochondrocytes proliferated within cartilage ring, and produced extracellular matrix. After 2 weeks of incubation, these inserted chondrocytes were significantly increased. There was no statistical y 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.
ABSTRACT
BACKGROUND:In joint surgery, the commonly used autologous chondrocyte transplantation often used to repair cartilage defects, and poor integration is one of the reasons that leading to failure repairing. Chondrocytes migration capability is proven to have correlation with integration and some pathways, such as Src-phosphorylated phospholipase Cγ1-extracellular regulated kinase 1/2 has been confirmed to have correlation with the migration ability of chondrocytes, but the correlation with the integration is stil unknown. OBJECTIVE:To determine the chondrocyte signaling pathways involved in autologous chondrocyte migration and their effects on cartilage integration in autologous chondrocyte implantation. METHODS:Articular chondrocytes were isolated from immature pig knee joints. The cells were divided into four groups:Src group, phosphorylated phospholipase Cγ1 group, extracellular regulated kinase 1/2 group and control group, then the Boyden chambers were used to quantify the chondrocyte migration. The chondrocytes/cartilage ring integration model was developed and cultured for 28 days, and then histology, biochemistry, biomechanics, western blot analysis and celltracking analysis were performed to observe the differences between the control group and the suppression groups. RESULTS AND CONCLUSION:The migration ability of chondrocytes was significantly decreased after pretreated with inhibitors. After the chondrocytes/cartilage ring co-cultured for 28 days, Western blot analysis showed that the pathway inhibitors has been presented in the entire culture cycle. The number and length of chondrocytes migrated into the integration area, col agen secretion level, matrix and mechanical strength in the control group were higher than those in three suppression groups. The results suggest that chondrocyte migration ability can affect the cartilage integration capability through Src-phosphorylated phospholipase Cγ1-extracellular regulating kinase 1/2 signal transduction pathway.