[Research on the repair of acute large osteochondral defects with mosaicplasty associated with genes-enhanced tissue engineering in different proportion].

OBJECTIVE

To investigate the optimum proportion of Mosaicplasty and genes-enhanced tissue engineering for the repair of acute osteochondral defects.

METHODS

Western blot test was conducted to detect the expression of hTGF-beta1, Col II and Aggrecan in 3 groups, including hTGF-beta1, transduction group, Adv-betagal transduction group and control group without transduction. Eighteen 6-month-old Shanghai male goats (weight: 22 to 25 kg) were used. BMSCs were isolated from the autologous bone marrow, and were subcultured to get the cells at passage 3. Thirty-six medial femoral condyles were used and divided into 6 groups named AR, AL, BR, BL, CR, and CL. Acute cylindrical defects (9 mm in diameter and 3 mm in depth)were created in the weight bearing area of the medial femoral condyle of hind limbs. In the single group, the autologous osteochondral mosaicplasty was performed to repair the defect; in the combination group, besides the mosaicplasty, the dead space between the cylindrical grafts and the host cartilage were injected with the suspension of hTGF-beta1, gene enhanced autogenous BMSCs in sodium alginate, and CaCl2 was dropped into it to form calcium alginate gels. The autologous osteochondral transplantation cover rates of group AR was 44.44% single group, AL was 44.44% combination group, BR was 33.33% single group, BL was 33.33% combination group, CR was 22.22% single group, and CL was 22.22% combination group. The goats were killed 24 weeks after operation to receive gross and histology observation, which was evaluated by the histological grading scale of O'Driscoll, Keeley and Salter. Immunohistochemistry and TEM observation were also performed.

RESULTS

Western blot test showed the expression of the hTGF-beta1, Col II and the Aggrecan in the hTGF-beta1 transduction group were significantly higher than that of the Adv-betaga1 transduction and the blank control groups. The gross and histology observation revealed that each defects of six groups had different degrees of repairing. There was no significantly difference among the BL, AR, and AL groups. But the scores of the other three groups (BR, CR, and CL) were significantly poorer than the former three groups.

CONCLUSION

Mosaicplasty associated with genes enhanced tissue engineering could repair the osteochondral defects effectively. With the autologous osteochondral transplantation coverage reducing, the advantage of the combination could have a better representation.