The addition of mesenchymal stem cells in a bioabsorbable scaffold does not enhance tendon healing after a repair of rotator cuff tear.

ABSTRACT

PURPOSE: The purpose of the study is to evaluate the healing potential of a full-thickness tendon defect in the rotator cuff of rabbits using a bioabsorbable scaffold impregnated with bone marrow-mesenchymal stem cells (BM-MSCs) or rotator cuff-derived mesenchymal stem cells (RC-MSCs). METHODS: Sixteen adult rabbits were subjected to a full-thickness rotator cuff deficit. Rabbits were randomly assigned to four groups of four animals. In Group 0 (control), the deficit was left untreated. In Group 1, the deficit was treated with a single synthetic scaffold alone. In Group 2, the deficit was treated with the previous scaffold loaded with allogeneic BM-MSCs. In Group 3, the deficit was treated with the previous scaffold loaded with allogenic RC-MSCs. After animal sacrifice, tissue samples were subjected to histological and immunohistochemical analysis. RESULTS: Group 1 showed the highest mean tendon maturing score (15.3 ± 0.9) postoperatively, being significantly higher, in comparison to groups 0, 2 and 3 (p = 0.01, 0.02 and 0.01, respectively). Group 1 showed the highest mean collagen I/collagen III ratio (1.4 ± 0.8) postoperatively but without any statistical significance. CONCLUSIONS: The utilization of MSCs in rotator cuff repair in a rabbit model has not been associated with an enhancement in tendon healing in 16 weeks postoperatively, in comparison to controls and bioabsorbable scaffolds. The addition of MSCs does not result in better rotator cuff healing. LEVEL OF EVIDENCE Not applicable. This is an animal study.