Objective: To evaluate the effectiveness of autologous adipose derived mesenchymal stem cells (ADSCs) transduced by adenovirus-mediated human transforming growth factor 2 (Ad-hTGF-beta2) gene in the repair of articular cartilage defects.
Methods: Rabbit ADSCs were obtained, cultured, and transfected with Ad-hTGF-beta2 containing human transforming growth factor (hTGF)-beta2. Three days later RT-PCR was used to detect the mRNA expression of hTGF-beta2 in the ADSCs, and ELISA was used to detect the protein expression of hTGF-beta2 in the supernatant. phosphorylation of Smad was examined by Western blotting. Articular cartilage defects at the femoral trochlea were made on 20 rabbits (40 sides) so as to establish animal models. The culture-expanded rabbit ADSCs transfected with Ad-hTGF-2 were seeded on poly (L-lactic-co-glycolic acid) (PLGA) scaffolds. The cell-adhered PLGA scaffolds were implanted into the articular cartilage defects. Plain PLGA was implanted into the left-side defects of 10 rabbits as control group and the defects of 10 sides remained untreated as blank control group. The rabbits were sacrificed 4, 12, and 24 weeks after the operation respectively. The specimens of defects were examined histologically and stained immunohistochemically for type II collagen.
Results: After transfection the ADSCs expressed mRNA and protein expression of hTGF-beta2 and Western blotting showed bands of phosphorylated Smad. The cartilage specimens harvested from the experimental group rabbits demonstrated hyaline cartilage formation mingled closely with the nearby tissues and expression of type II collagen. However, only fibroblasts, not cartilage-like cells, were seen in the control groups that lacked the expression of type II collagen too.
Conclusion: Culture-expanded autologous ADSCs adhered with PLGA composites facilitate the formation of hyaline-cartilage.