Joint Regeneration with Tissue Engineering Techniques

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 16591490
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Orthopaedic surgery
• Research Institution: Shimane University
• Principal Investigator: UCHIO Yuji Shimane University, Faculty of Medicine, Professor, 医学部, 教授 (20223547)
• Co-Investigator(Kenkyū-buntansha): MANIWA Sokichi Shimane University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (50239141) ; MORI Ryuji Shimane University, Faculty of Medicine, Associate Professor, 医学部, 助教授 (40263537) ; IWASA Junji Shimane University, Faculty of Medicine, Assistant Professor, 医学部, 講師 (20294382)
• Project Period (FY): 2004 – 2006
• Keywords: Tissue Engineering / Cartilage / Bone / MC3T3-E1 / Surface

Research Abstract

Since defects of articular cartilage are not regenerated spontaneously, artificial material is used for joint reconstruction. Although artificial joints are useful for a whole, they sometimes end up with loosening and deep infection. Thus it would be beneficial if reconstructed joints consisted of living tissue only. We aimed to regenerate joints with cells, which are prepared from extra-cartilage and proliferate ex vivo.
The first experiment was conducted to evaluate the feasibility of extra-cartilage tissue for the candidate of cell source to regenerate cartilage. Synovial cells were differentiated into chondrocyte-like cells in terms of the expression of type II collagen with the presence of TGF-b, although their number was much lower than our expectations. Cells from bone marrow and striated muscle hardly resembled chondrocytes. Three-dimensional cultures with collagen gel did not allow proliferation of the cells. Most cells even died in the deep layer of the gel, though cells near the surface proliferated and resembled chondrocytes. The supplement of hydroxyapatite in collagen gel did not alter in any biological aspect in cell culture systems. Therefore the combination of extra-cartilage cells and collagen gel may not be a practical candidate to reconstruct a whole joint.
Then we evaluated the advantage of biological tissue "bone" as a carrier of cells. Bone blocks were made from bovine cortical bone and their surface was precisely engineered to have certain types of surface. MC3T3-E1 cells were cultured on the bone blocks. The bone surface with parallel micro-groove (Ra 50μm) promoted migration of cells of which shape was narrow spindle. In contrast, rough surface with various sizes of pits did not accelerate migration but promoted the formation of multi-layer colony of polygonal cells. Precisely engineered bone was evaluated also in vivo system. Bony screws, which were made from bovine bone and implanted into the knee joints of rabbits, were integrated within 2 weeks and replaced with living bone of rabbits within 3 months. These findings imply that bone tissue shall be a great advantage as a scaffold of cells that are harvested from extra-cartilage for cartilage regeneration.