Effects of marine collagen and ascorbic acid on the tendon repair in the rat model: a biomechanicaland histopathological study.

Background: Tendon injuries are common and can lead to significant morbidity. Marine collagen and ascorbic acid have shown potential for promoting tendon repair and regeneration. Aims: This study investigated the effects of marine collagen, ascorbic acid, and their combination on tendon healing in a rat model over 6-week duration. Methods: Sixty adult male Wistar rats were randomized into four equal groups: control, collagen + ascorbic acid, collagen, and ascorbic acid. A controlled full-thickness transverse incision was made in the mid-portion of the Achilles tendon to induce injury, and the defects were sutured following treatment. The treatments were administered orally for 30 days. Tendon recovery was evaluated through histopathological assessments after 30-day treatment at 2-, 4-, and 6-weeks post-operation and biomechanical properties analyzed at 6 weeks. Results: Histological evaluation revealed significantly higher connective tissue and collagen accumulation in the collagen + ascorbic acid group (75-90%) compared with the collagen (50-75%), ascorbic acid (25-50%), and control groups (25-50%) (P<0.05). Biomechanical analyses showed at 6 weeks after surgery that the collagen + ascorbic acid group had significantly higher maximum force (28.6 ± 3.2 N), maximum stress (4.8 ± 0.6 MPa), work (90.4 ± 11.3 N.mm), and yield points (18.9 ± 2.1 N) compared to the collagen, ascorbic acid, and control groups (P<0.05). Conclusion: The combined supplementation of marine collagen and ascorbic acid significantly enhanced tendon healing, as evidenced by improved histopathological and biomechanical parameters. These findings suggest that this combination is a promising therapeutic strategy for tendon repair and regeneration.