Injectable Cartilage Tissue Engineering Techniques Utilizing Fibrin Glue, Liquid Alginate and Pluronic F-127

ABSTRACT

Recently, a cartilage tissue utilizing the scaffold with liquid has been introduced for clinical application. In this study, three different bio-materials--fibrin glue, liquid alginate, and Pluronic F-112--were used to observe the feasibility of those liquid bio-materials in cartilage regeneration. The first stage of the experiment comprises gross observation of liquid bio-materials 24 hours after its injected into the subcutaneous pockets of New Zealand white rabbits. These bio-materials shows noticeable changes within the subcutaneous tissue of animal recipients. The second stage of the experiment is cartilage tissue engineering in athymic nude mouse utilizing these liquid bio- materials. Chondrocytes were harvested from the ear cartilage of rabbits. Tissue engineered constructs(TEC) were prepared by mixing the bio-materials and chondrocytes as 3 x 10(6) cells/ml. The TEC were injected into the dorsal subcutaneous tissue of rabbits as autologous grafts. The specimens were then harvested and analysed grossly and histologically at 4 weeks after injection. The sizes of the engineered cartilage tissue specimens varied according to the scaffold materials. The histologic evaluation was also performed after using the H/E stain and alcian blue stain. The specimen using fibrin glue showed homogeneous typical mature cartilage with lacunae surrounded by cartilage matrix. The specimen using liquid alginate showed homogeneous but relatively immature cartilage tissue formation throughout the specimen. The specimen using the Pluronic F-127 complex showed small areas of cartilage tissue islets which were less homogeneous in its distribution. In conclusion, it was possible to produce cartilage tissue by utilizing liquid scaffolds, such as fibrin glue, liquid alginate and Pluronic F-127. The cell-scaffold complex (TEC) could be successfully injected into subcutaneous tissue and changed into a semi-solid gel which ultimately produces a small amount of cartilage. This new concept of non-operative reconstruction method can be used for a variety of clinical purposes in the future.