Summary

Polydeoxyribonucleotide and polynucleotide may improve tendon healing and decrease fatty degeneration after cuff repair in rat model. Thus, they might also exert such effects in humans.

Abstract

Introduction

After surgical repair of chronic rotator cuff tears, healing of the repaired tentons often fails, accompanied by high-level fatty degeneration. Our purpose was to explore the effects of polydeoxyribonucleotide (PDRN) and polynucleotide (PN) on tendon healing and reversal of fatty degeneration in a chronic rotator cuff tear model using a rat infraspinatus.

Methods

60 rats were randomly assigned to three groups (20 rats per group: 12 for histological evaluation and 8 for mechanical testing): saline+repair (SR), PDRN+repair (PR), and PN+repair (PNR). The right shoulder was used for experimental interventions, and the left served as a control. Four weeks after detachment of the infraspinatus, the torn tendon was repaired. Saline, PDRN, and PN were applied to the repair sites. Histological evaluation was performed at 3 and 6 weeks after repair and biomechanical analysis was performed at 6 weeks.

Results

At 3 weeks, the collagen fibers werepoorly organized, and fiber continuity was not established in all groups compared with the control group. However, the PR and PNR group had better-organized collagen fibers than did the SR group, and the PNR group exhibited less fatty degeneration than the SR group. At 6 weeks, tendon-to-bone integration was markedly improved with more collagen fiber, and parallel orientation in all groups. The PR group had more parallel collagen fibers and less fatty degeneration than the SR group. The PNR group exhibited more continuous parallel collagen fibers and less fatty degeneration than the SR group, and less fatty degeneration than the PR group. On biomechanical evaluation, the mean load-to-failure of the PR (17.5±7.9 N) and the PNR (17.2±8.7 N) groups were higher than that of the SR group (11.3±5.8 N), although these differences were not significant (P=.180, and P=.338, respectively).

Conclusion

PDRN and PN might have possibility to improve tendon healing and decrease fatty degeneration after cuff repair.
Study design: Controlled laboratory study.