Enhanced Scar Reduction Using Topical Application of Captopril-containing Silicone Gel in a Rabbit Model of Hypertrophic Scars.

Abstract

Antihypertensive medications, including angiotensin-converting enzyme (ACE) inhibitors and calcium channel blockers, have been explored for their potential in treating pathological scars. We compared the scar-reducing effects of topical silicone and captopril (an ACE inhibitor) gel used alone and in combination. Eight New Zealand White rabbits with a total of 80 wounds on both ears were used. The animals were assigned to the control, vehicle, silicone, and captopril 50 mg/g and 50 mg/g captopril-containing silicone groups (n = 16 per group). Treatment began on day 28 post-scarring. The scar elevation index (SEI) was measured by histopathology. Scarring was assessed based on fibroblast counts, capillary counts, and epithelial thickness. Ki-67, collagen type I and III, and vascular endothelial growth factor (VEGF) expression was evaluated using immunohistochemistry. SEI, fibroblast and capillary counts, epithelial thickness and collagen type I and III expression were significantly lower in the captopril-containing silicone group than in the other groups (P < 0.001). Ki-67, and VEGF expression also showed significant decreases in the silicone, captopril 50 mg/g, and captopril-containing silicone groups compared with the control and vehicle groups (P < 0.001). Topical application of captopril 50 mg/g alone or in a captopril-containing silicone formulation effectively reduced scar formation, with enhanced effects observed when captopril was combined with silicone. Captopril, therefore, presents a viable alternative to conventional silicone for scar management across various clinical scenarios.