The efficacy of angiotensin-converting enzyme inhibitors in preventing postoperative tendon adhesion formation: An experimental study in rats

Objective: The aim of this study was to investigate the efficacy of angiotensin-converting enzyme inhibitors (ACEIs) in preventing postoperative tendon adhesion formation in a rat model of Achilles tendon repair. Methods: In this study, 60 Sprague-Dawley male rats weighing 300 to 350 g were used. Rats were randomly divided into six groups (n = 10 per group): control-1, control-2, sham-1, sham-2, experiment-1, and experiment-2. The same surgical procedure was performed in all rats; a full thickness Achilles tenotomy was performed, and the tendon was repaired using a modified Kessler suture. Enalapril (10 mg/kg/day) was orally given to the Experiment-1 and Experiment-2 groups for three and six weeks, respectively. Thirty rats were sacrificed at three weeks (Control-1, Sham-1, Experiment-1); the remaining 30 rats were sacrificed at six weeks (Control-2, Sham-2, Experiment-2). Then, macroscopic, biomechanical, and histologic investigations were performed. Results: Adhesion degree was found macroscopically lower in the Experiment-1 and 2 groups than others. In the histologic examination, the fibrosis level was found the lowest in the Experiment-2 group. Biomechanical evaluation indicated that mean maximum resistance before tendon rupture was significantly higher in the Experiment-2 group than in other groups. Conclusion: Evidence from this study has shown that ACEIs can decrease fibrosis and tendon adhesion during tendon recovery in rats due to their antifibrotic effects as the result of Angiotensin-II suppression.