The effect of angiotensin converting enzyme inhibitors and angiotensin receptor blockers on tendon healing

Fatih Korbay, The Effect of Angiotensin Converting Enzyme Inhibitors and Angiotensin Receptor Blockers on Tendon Healing, Bulent Ecevit University School of Medicine, Thesis in Orthopedics and Traumatology. Zonguldak, 2015. Renin-Angiotensin System (RAS) inhibition shows antifibrotic features. The effect of renoprotectivety and cardioprotectivety clinically used (RAS) is also proved to be effective to block extraviseral fibrotic processes. In this research, it was aimed to investigate the effects of RAS's inhibition with ACEi and ARB and its fibrojenical effects on tendon healing process. In this study; rat Achilles tenotomy and repair model was used. The study was designed as three groups as; Control, ARB group and ACE group. Under general anesthesia, a transverse incision was surgically made on middle thirds of rat left Achilles tendon, followed by repair with 3.0 polypropylene suture. Afterwards the rats were left to their natural environment and 10 mg/kg Losartan was administered to ARB group and 10mg/kg Enalapril was administered to ACE group by giving the drugs with gavaj method. Rats were sacrificed at 3nd and 5th weeks for histopathological evaluation. Histological evaluation revealed that local Angiotensin-II suppression shows anti-fibrotic effect in rat tendon healing model by decreasing both TGF-β (Transforming Growth Factor- beta) and the amount of collagen. Inflammation and neovascularization are both suppressed by ACEi and ARB. Fibroblastic proliferation, the amount of TGF-β ın the tissue and the amount of collagen are suppressed by ACEi more effectively. Local renin-angiotensin system inhibition is effective on fibrotic processes seen on musculoskeletal system beside visceral fibrosis. Keywords: Tendon healing, Angiotensin Converting Enzyme Inhibitor, Angiotensin Receptor Blocker, Hypertension, Fibroblast