Promising results of captopril in improving knee arthrofibrosis and cartilage status: an animal model study

PURPOSE: Several cytokines and growth factors start and progress the destruction process of joint hyaline cartilage and fibrosis formation. Captopril is classified as an Angiotensin-converting enzyme inhibitor in which several studies revealed that captopril significantly decreases fibrosis formation in some organs like the liver, heart, and kidney. This study aimed to evaluate the use of captopril in reducing the possibility of arthrofibrosis and osteoarthritis in an animal model. METHOD: In this in-vivo animal model study, the anterior cruciate ligament of 24 rabbits was transected to induce osteoarthritis and arthrofibrosis. The control group contained 11 rabbits and the second group consisted of 13 rabbits. The second group was treated with 10 mg/ kilogram/day captopril through a nasogastric tube. The control group was treated with normal saline in the same way. Cartilage damage and osteoarthritis were evaluated by Osteoarthritis Research Society International (OARSI) scoring system. After 30 days, animals were sacrificed, and arthrofibrosis and cartilage damage were evaluated microscopically and macroscopically. RESULTS: According to macroscopic and microscopic evaluation, captopril dramatically reduced arthrofibrosis formation based on visual scoring and the Masson trichrome staining system. Cartilage damage was lower in the intervention group compared to the control group. CONCLUSIONS: Captopril is an angiotensin-converting enzyme inhibitor that demonstrated to significantly decreases the possibility of arthrofibrosis. Although the beneficial preventive effect of captopril on osteoarthritis was not proved statistically, better results may be obtained if the route of administration or drug dosage is changed.