Fabrication of Atelocollagen-Coated Bioabsorbable Suture and the Evaluation of its Regenerative Efficacy in Achilles Tendon Healing using a Rat Experimental Model

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Bioaborbable sutures composed of poly (lactic-co-glycolic acid) (PLGA) are commonly used in Achilles tendon rupture (ATR) surgeries. Nevertheless, owing to the inherent limitations of PLGA, novel bioabsorbable sutures that can accelerate Achilles tendon healing are needed. Recently, several studies have demonstrated the beneficial effects of atelocollagen on tendon healing. In this study, poly (3,4-dihydroxy-L-phenylalanine) (pDOPA), a hydrophilic biomimetic material derived from mussel, was used to modify the hydrophobic surface of a PLGA suture (Vicryl, VC) for the stable coating of atelocollagen on its surface. The main objective was to fabricate an atelocollagen-coated VC suture and evaluate its performance in the healing of Achilles tendon using a rat model of open repair for ATR. Methods: To induce a strong interaction between the Vicryl suture and collagen, the surface of the Vicryl suture was first coated with pDOPA using a simple DOPA dip-coating process to obtain VC/pDOPA. Then, collagen was successfully coated on the VC/pDOPA surface via a dip-coating process, and the presence of pDOPA was confirmed through surface analysis and water contact angle measurements. For in vivo experiments, 42 adult male rats were randomly divided into three groups: Vicryl group (VC group; n= 14), VC/pDOPA group (n = 14), and VC/pDOPA/Col group (n = 14). At 1 and 6 weeks following open tenotomy, the animals were euthanized. For each group, four specimens were used for biomechanical assessments and three were used for histological assessments. Transmission electron microscopy images were obtained from three rats in each group. For quantitative molecular analysis, western blot was performed on three rats from each group at week 1 and 6. Results: Structural analyses of the surface-modified suture indicated that the collagen was successfully coated on the VC/pDOPA suture. Postoperative in vivo biomechanical analysis, histological evaluation, ultrastructural/morphological analyses, and western blotting confirmed that the tendons in the VC/pDOPA/Col group exhibit superior healing than those in the VC and VC/pDOPA groups after 1 and 6 weeks following the surgery. Conclusion: This study demonstrate that atelocollagen-coated PLGA/pDOPA sutures could become favorable candidates for future medical applications, especially in repair of ATR. The molecular data indicated that the coating of atelocollagen on suture may be associated with an increased amount of collagen type I. The scheme and the outcomes of the present study 1.Schematic illustration of the experimental procedures. 2.In vivo experimental schedule and surgery in the present study. 3.Schematic illustration of the coating of pDOPA on the surface of the Vicryl (VC) suture and interactions between pDOPA and VC. 4.Surface analysis of VC/pDOPA with SEM images, N content, and water contact angle. 5.Schematic illustration of the dip-coating of collage on the hydrophilic VC/pDOPA surface. 6.Mechanical evaluation of the suture and tendon. 7.Histological analysis of the tendons. 8.TEM analysis. 9.Western blot analysis.