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[Articular cartilage defects repaired with homograft of mesenchymal stem cells seeded onto medical collagen membrane of guided tissue regeneration].

OBJECTIVE
To investigate the curative effects of homograft of the mesenchymal stem cells (MSCs) combined with the medical collagen membrane of the guided tissue regeneration(MCMG) on the full thickness defects of the articular cartilage.


METHODS
MSCs derived from New Zealand rabbits aged 3-4 months weighing 2. 1-3.4 kg were cultured in vitro with a density of 5.5 x 10 (8)/ml and seeded onto MCMG. The MSC/MCMG complex was cultured for 48 h and transplanted into the full thickness defects on the in board condyle and trochlea. Twenty-seven healthy New Zealand rabbits were randomly divided into 3 groups of 9 rabbits in each. The cartilage defects in the in board condyle and trochlea were filled with the auto bone marrow MSCs and MCMG complex (MSCs/ MCMG) in Group A (Management A), with only MCMG in Group B (Management B) and with nothing in Group C (Management C). Three rabbits were killed at 4, 8 and 12 weeks after operation in each group, and the reparative tissue samples evaluated grossly,histologically and immunohistochemically were graded according to the gross and histological scale.


RESULTS
Four weeks after transplantation, the cartilage and subchondral bone were regenerated in Group A; for 12 weeks, the regenerated cartilage gradually thicker; 12 week after transplantation, the defect was repaired and the structures of the articular surface and subchondral bone was.in integrity. The defects in Group A were repaired by the hyaline-like tissue and the defects in Groups B and C were repaired by the fibrous tissues. Glycosaminoglycan and type II collagen in Groups A, B and C were reduced gradually. The statistical analysis on the gross at 12 weeks and the histological gradings at 4 weeks, 8 weeks and 12 weeks showed that the in board condylar repair had no significant difference compared with the trochlearepair(P>0. 05). Management A was significantly better than Managements B and C (P<0. 05), and Management B was better than Management C (P<0. 05).


CONCLUSION
Transplantation of the MSCs combined with MCMG on the full thickness defects of the articular cartilage is a promising approach to the the treatment of cartilage defects. MCMG can satisfy the demands of the scaffold for the tissue-engineered cartilage.