Experimental Studies Of Stabilized Fibrin-chondrocyte Constructs On The Repairing Defects Of Articular Cartilage

Objective: In order to improve the properties of fibrin glue, aprotinin and tranexamic acid were added to fibrin glue. Stabilized fibrin-chondrocyte constructs were cultivated in vitro and the procedure of degradation was observed. In order to find a way of stabilizing fibrin by increased fibrinolytic inhibition in vivo, the effects of Stabilized fibrin-chondrocyte constructs and standard fibrin-chondrocyte constructs on the repairing defects of articular cartilage were studied. The quality of neocartilage was improved as reaching the balance between FG degradative speed and extracellular matrix formation so to develop a new kind of absorbable tissue engineering scaffold of cartilage. Methods: 1. The chondrocytes from articular cartilage of 3 weeks old New Zealand rabbit were Isolated and monolayer cultured, then the cultured chondrocytes were seeded on the FG scaffold. The stabilized fibrin-chondrocyte constructs and standard fibrin-chondrocyte constructs were cultured and amplified for 6 weeks in three-dimensional spatial in vitro. The behavior of chondrocytes cultured in fibrin glue was observed by histology and electron microscopy. The mass and degradation speed of fibrin-chondrocyte constructs were evaluated in different periods. 2. Two defects of articular cartilage were made in the trochlear groove of each group of rabbit. The group A and B were filled with standard/ stabilized fibrin-chondrocyte constructs respectively. The group C was left empty. The repair of defects was periodically examined grossly, histologically and histochemically after the operation of 6,12 and 18 weeks respectively. In addition, the Glycosaminoglycan (GAG) content of the normal cartilage and the neocartilage after 18 weeks of transplantation was determined. Results: 1. The alcian blue stain of two groups of constructs was positive, electron microscopy indicated that cultured chondrocytes in FG constructs could excrete extracellular matrix. 2. The mass of standard/ stabilized fibrin-chondrocyte constructs was (125.85 + 17.63) mg and (145.13 + 19.83) mg on the first week, (73.72 + 11.02) mg and (117.78 + 14.00) mg on thesecond week respectively. The difference was statistically significant. Stabilized fibrin-chondrocyte constructs shrank slightly within 4 weeks. 3. The doubling time of standard/ stabilized fibrin-chondrocyte constructs was 5.0 days and 4.7 days respectively. The difference was not statistically significant. 4. The neocartilage of group B was better than that of group A after 18 weeks of transplantation. The feature of neocartilage (group B) was similar to that of the adjacent normal cartilage. 5. the GAG content of the repair tissue of group B (68.08 + 7.52) p, g/5mg reached the level of normal cartilage (69.59 +6.18) JJL g/5mg after 18 weeks of transplantation. The difference was not statistically significant (P=0.628). the GAG content of the neocartilage of group A (60.85 + 6.84)(jig/5mg was lower than that of the normal level. The difference was statistically significant (P=0.008). Conclusion: l.The degradative speed of FG is slowed significantly by aprotinin and tranexamic acid. Chondrocytes are viable in stabilized FG scaffold and can produce a cartilage-specific extracellular matrix in vitro. 2. The degradative speed of FG is also slowed by aprotinin and tranexamic acid in vivo. The quality of neocartilage is improved as reaching the balance between FG degradative speed and extracellular matrix formation. 3. The stabilized fibrin-chondrocyte constructs can induce cartilage regeneration and repair the defects of cartilage with hyaline cartilage. The quality of neocartilage of group B is better than that of group A and C. Cell factors and organism-press in vivo are very important in forming articular cartilage. 4. The degradative speed of FG can be controlled by adjusting the content of aprotinin and tranexamic acid. The scaffold of stabilized FG. is fit for different cell seeds. The stabilized FG for cartilage reconstruction has many advantages compared with the standard FG.