[Repair of chondral defects of the knee using a combination of autologous chondrocytes and osteochondral allograft--an animal model. Part I: in vitro culture of autologous chondrocytes].

PURPOSE OF THE STUDY: In the study we used in vitro cultivated autologous chondrocytes in combination with osteochondral allografts for the treatment of local defects of articular cartilage on the animal model (rabbit).

MATERIAL: Chondrocytes for in vitro cultivation were harvested by biopsy of articular cartilage of rabbit. For the monolayer cultivation we used Nutrient mix F 12 (Gibco BRL) with addition of Lascorbic acid (50 micrograms/ml, Sigma) and insulin-trasferin-selenium (A 6.26 micrograms/ml, Gibco BRL), 20% of fectal serum (Gibco BRL) and antibiotic antimycotic solution (Gibco BRL). Cultivation of chondrocytes took place at 37 degrees in the atmosphere of 5% CO2. Multiplied chondrocytes re-suspended in fibrin glue in combination with two osteochondral allografts were used for the reparation of artificial defect of the rabbit cartilage.

METHODS: For the analysis of collagen type II in the cultivation medium we used the principle of salting out by 30% ammonium sulphate and subsequent pepsinization in an acid environment with a repeated salting out by means of 2M of NaCl. Precipitates were dissolved in 5.0 M of acetic acid and used for SDS PAGE and immunoblotting. As a detection system we used ECL (Amersham/Pharmacia Biotech).

RESULTS: The final average number of chondrocytes multiplied by monolayer cultivation was 1.10(5). The presence of collagen of type II has proved the preservation of the original phenotype of chondrocytes during cultivation.

DISCUSSION: Bioengineering use of cell and tissue cultivation provides new options of the treatment of defect of connective tissue. Transplantation of autologous chondrocytes in combination with osteochondral allografts is on the basis of our results obtained so far a promising therapy.

CONCLUSION: The aim of our work was an ex vivo expansion of autologous chondrocytes for the purpose of cell transplantation.