Losartan in Situ Forming Gel as a New Treatment for Hypertrophic Scars

Hypertrophic scars are defined as visible lesions formed by excessive wound healing that cause cosmetic and, in some cases, functional challenges in patients. This study aimed to assess the efficacy of intralesional injections of losartan-loaded in situ forming gel and compare it with the common treatment (triamcinolone) in preventing scar formation. The formulation was prepared using a thermosensitive PLGA–PEG–PLGA triblock copolymer. Ear scar tissue in rabbits represented the hypertrophic scar, and the animals were treated with three treatments in three groups. Nine weeks following the single treatment, images of the scars were obtained and quantitatively analyzed using ImageJ and light microscopy was used to evaluate the fibroblast cell number, vascularization, inflammation and collagen deposition and fibrosis in H&E-stained sample tissue. According to the results based on the ImageJ and the Vancouver criteria, the losartan in situ forming gel (F-LG) indicated significantly higher improving effects on decreased vascularity and pigmentation in comparison with triamcinolone (F-TA) and placebo as a control (F-Ctl), although the effect F-LG was almost similar to F-TA on pliability and scar height, and they were better than the control. Histological findings showed F-LG and F-TA have less inflammatory and fibroblast cells compared to F-Ctl. Also, results indicated the dermal layers of the F-TA and F-LG groups’ scar were thinner, and the deposition of collagens was reduced compared to the control. Consequently, F-LG was found to be an effective treatment in reducing scarring and promoting wound healing.

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