Comparison of angiotensin converting enzyme inhibitor, angiotensin receptor blocker and steroid activity in rabbit ear experimental hypertrophic scar model

Deviations in the wound healing process result in characteristic hypertrophic scar with excessive scar. Hypertrophic scars, which are among the main issues that Plastic, Reconstructive and Aesthetic Surgery, lead to serious cosmetic and symptomatic problems. Although the events leading to hypertrophic scarring have been extensively studied, the etiopathogenesis is still unclear. Because of the little informations about etiopathogenesis has led to generally unsatisfactory results and new searches in treatment.Therefore, numerous experimental and clinical studies have been studied for this. In this study, angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) using the renin angiotensin system with corticosteroids were investigated on the hypertrophic scar formed in the animal model. For this purpose, 20 New Zealand rabbits were divided into five groups (A: Sham group, B: Control group, C: ACEi group, D: ARB group, E: Intralesional corticosteroid group). The skin, subcutaneous and pericondrium were removed from the ventral part of each ear of both rabbits and cartilage was left on the floor, and a hypertrophic scar model was designed by forming 4 pieces 6 mm diameter circular defects. The study was completed on the 40th day and samples were taken for histopathologic examination. Scar elevation index (SEI), fibroblast count, total collagen density, type 1 and type 3 collagen density, epithelialization, vascularization, inflammation and fibrosis were compared for each sample. In our study, corticosteroid group was the best group in terms of total collagen, SEI, low value of type 3 collagen, height of type 1 collagen value. Type 1 and type 3 collagen, epithelialization, vascularization, inflammation and fibrosis were not different between ACEi and ARB groups. ACEi group was found to be better than ARB group in terms of lowness fibroblast count, total collagen density, SEI. As a result, we found that the ACEi and ARB group drugs have a positive effect on hypertrophic scar treatment. We think that especially hypertensive patient with hypertrophic scar may prefer ACEI and ARB group drugs. However, there is a need for more empirical work on issues where we have conflicting results.