Summary

The application of decellularized tendon allogfraft seeded with BMSCs could achieve better results than allograft in ACL reconstruction surgery.

Abstract

Backgrounds: The free tendon allograft is a regular adoptable material for anterior cruciate ligament (ACL) reconstruction, but reconstruction using this material has exhibited a number of unsatisfactory outcomes, such as the retardation of both the ligamentization and tendon-bone integration process.

Objective

The purpose of this study was to investigate the efficacy and feasibility of using a pH modified decellularized allogenic semitendinous tendon (ST) combined with autologous BMSCs as a substitute for free tendon allograft in a rabbit model.

Materials And Methods

Eighty-six male skeletally mature New Zealand white rabbits were adopted. In the control group, 40 rabbits underwent ACL reconstruction with fresh frozen allogenic ST (FFA group). In the treatment group, 46 rabbits underwent ACL reconstruction with a pH- modified (approximately 7.2) decellularized allogenic ST combined with autologous BMSCs (BMSCs/DA group), and 6 of them were implanted with eGFP-transduced BMSCs for trace examination of the seed cells. The abilities of BMSCs/DA to improve graft remodeling and strengthen tendon bone integration were evaluated by histological analysis of the intra-articular and intraosseous portions of the graft, micro-CT analysis of bone mineral density (BMD) and bone volume/total volume (BV/TV) and mechanical testing of ultimate load and stiffness postoperatively at weeks 2, 4, 8 and 12. The seed cells trace examination by fluorescence and immunohistochemistry for eGFP-tagged BMSCs was performed postoperatively at weeks 4, 8 and 12.

Results

Autologous BMSCs implanted in combination with a decellularized allograft survived in vivo for at least 12 weeks. Compared to the common fresh frozen allograft, the BMSCs/DA group achieved earlier cellular ingrowths, blood vessel formation, collagen matrix remodeling and faster tendon-bone integration; bone tunnel wall osteogenesis and tendon bone healing strength were also significantly improved.

Conclusions

The pH-modified decellularized allogenic ST combined with autologous BMSCs showed significantly improved ACL reconstruction results compared to the common fresh frozen allograft.
Keywords: BMSCs (bone marrow-derived mesenchymal stem cells); ACL (anterior cruciate ligament); decellularized; allograft; ST (semitendinous tendon)