Objective: One of the most important clinical complications after tendon repair surgery is fibrosis and adhesion formation, and some studies have shown that angiotensin II is responsible for pathological scarring and fibrosis. Enalapril, an angiotensin-converting enzyme inhibitor, inhibits excessive fibrosis and hypertrophic scarring while reducing conversion to angiotensin II. However, the effects of enalapril on skin fibrosis and peritendinous adhesion on tendon injuries remain unknown. We aimed to investigate the effects of enalapril on peritendinous adhesion and skin fibrosis during the extrinsic healing period of the tendon.

Materials and Methods: Twenty-one rats were randomly divided into three groups: sham (Group S), control (Group C) and enalapril (Group E). Both hindlimbs were operated. In Group S, the Achilles tendon was disassembled so that only the tendon sheath was opened. In groups C and E, the Achilles tendon was transversally and completely cut and then repaired. Postoperatively, only Group E was provided enalapril treatment for 28 d via oral gavage. Full-thickness Achilles tendon biopsies with skin were taken from healing regions to evaluate peritendinous adhesion and skin fibrosis.

Results: The formation of skin fibrosis, but not of peritendinous adhesion, was significanly lower in the enalapril group.

Conclusion: Enalapril reduces fibrosis in skin or subcutaneous tissues but has no significant effect on epitendineum and tendon structure.