NaHS-Hydrogel and Encapsulated Adipose-Derived Stem Cell Evaluation on an Ex Vivo Second-Degree Burn Model

Second-degree burns result in the loss of the epidermal barrier and could lead to delayed complications during the healing process. Currently, therapeutic options to treat severe burns are limited. Thus, this work aims to evaluate the effect of NaHS, a hydrogen sulfide (H2S) donor, in poloxamer hydrogel in topical application and the potentiating effect of injected encapsulated adipose-derived stem cells (ASCs) compared to monolayer ASCs using our previous second-degree burn model on human skin explants. Indeed, our model allows testing treatments in conditions similar to a clinical application. The observed benefits of NaHS may include an antioxidant role, which might be beneficial in the case of burns. Concerning ASCs, their interest in wound healing is more than well documented. In order to evaluate the efficiency of our treatments, we analyzed the kinetics of wound closure, keratinocyte proliferation, and dermal remodeling. The effect of NaHS led to a delay in re-epithelialization, with a decrease in the number of proliferating cells and a decrease in the synthesis of procollagen III. On the contrary, intradermal injection of ASCs, encapsulated or not, improves wound healing by accelerating re-epithelialization and collagen I synthesis; however, only encapsulated ASCs accelerate keratinocyte migration and increase the rate of procollagen III and collagen III. In conclusion, NaHS treatment did not improve burn healing. However, the injection of ASCs stimulated wound healing, which is encouraging for their therapeutical use in burn treatment.