Articular cartilage is a tissue with limited capacity of self regeneration. Chondrocytes implantation is becoming a widely used method for treating defects of articular cartilage of weight bearing joints. Injection of in vitro multiplied autologous chondrocytes under the periostal flap is the method accepted as a classical Brittberg´s method--generally applied in human clinical practice. In the present study we investigated two different approaches of autologous versus allogeneic chondrocytes implantations for rabbit knee cartilage defects repair.
Materials & Methods
Rabbit knee cartilage was harvested by biopsy and used for collagenase type II digestion to obtain single living chondrocytes for their in vitro cultivation. Two different methods of chondrocytes cultivation were used: monolayer and 3D cultivation in collagen hyaluronan scaffold membrane. Twelve adult rabbits were used for transplantation. Two different approaches were used: transplantation of autologous and allogeneic ex vivo expanded chondrocytes. Artificial defect, 3mm in diameter, on medial femoral condyle was formed. Chondrocytes in fibrin glue (Tissucol, Baxter, USA ) under the immobilized collagen hyaluronan membrane resp. collagen hyaluronan membrane seeded and cultivated with chondrocytes were used as an implants for cartilage lesion repair. Four groups, each consisted of 3 rabbits were formed. Cultured autologous chondrocytes in group A, cultured allogeneic chondrocytes in group B were first resuspended in fibrin glue and injected under the collagen hyaluronan membrane, attached by fibrin glue on the lesion surface. Chondral defect in group C was filled with collagen hyaluronan scaffold seeded with autologous chondrocytes and cultivated until suitable concentration was formed. Control group D was left without any chondral defect repair. Three months after the surgery femoral condyles were collected and histologically evaluated.
Histological evaluation of articular cartilage repair after three months.
Group A implant ( autologous chondrocytes in fibrin glue under membrane ): scaffold damaged, hyaline-like cartilage formation with well proliferated chondrocytes on the defect base.
Group B implant (allogeneic chondrocytes in fibrin glue under membrane): proliferation of chondrocytes slightly weaker. Evidence of regeneration without inflammation.
Group C implant (3D scaffold seeded and cultivated with autologous chondrocytes): regeneration of the chondral defect by hyaline-like cartilage formation.
Control group D (no implant): hyperplastic regeneration of fibrous cartilage.
In all types of implants used in this study, positive effects on articular cartilage regeneration was achieved. 3D scaffolds seeded and cultivated with auto-resp. allogeneic chondrocytes had positive effects on new cartilage formation. No immunological reaction was observed when allogeneic cells were used. Very weak adhesive properties on surrounded tissue were observed when fibrin glue/chondrocytes mixture was used as a chondrocytes scaffold.