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Abstract Objective This study aimed to explore the effects on controlling infection and promoting wound healing in deep burn injuries by crosslinking ASCs-Exos with CS-αβ-GP thermosensitive hydrogel. Methods Rats with established deep burn injury models were divided into four groups: CS + ASCs-Exos group, ASCs-Exos group, CS group, and control group. The wound healing rates were analyzed and calculated using Image J software immediately after wound formation and on days 2, 4, 6, 8, 10, 12, and 14 after treatment. Fourteen days after treatment, skin tissues from the wound area, wound margin, and normal full-thickness skin were excised from each group for HE staining and Masson staining. Subsequently, IHC staining was performed on the newly formed wound tissues to detect the expression of TNF-α, IL-6, IL-1α, IL-10, TGF-β, and EGF. Finally, RNA was extracted from the wound tissues, and qPCR was used to detect the mRNA expression levels of IL-1α, CD86, CCL22, and CD163. Results The wound healing rate in the CS + ASCs-Exos group was higher than that in the other groups. HE staining revealed that the CS + ASCs-Exos group had fewer inflammatory cells, a small number of blood vessels, and muscle fibers and collagen fibers distributed alternately in the wound edge at 14 days, which was consistent with normal tissue. Masson staining showed that the wound and wound edge in the CS + ASCs-Exos group at 14 days displayed alternating distributions of collagen fibers and muscle fibers, which was consistent with normal tissue. However, the staining of collagen fibers in the other groups was stronger than that in the experimental group. IHC staining showed that the expressions of IL-10, TGF-β, and EGF in the CS + ASCs-Exos group were slightly higher than those in the other groups, while the expressions of TNF-α, IL-6, IL-1α, and IL-10 were lower than those in the other groups. qPCR detection revealed that the expressions of IL-1α and CD86 in the CS + ASCs-Exos group were lower than those in the control group, while the expressions of CCL22 and CD163 were higher than those in the control group. Conclusion Our research has demonstrated that ASCs-Exos crosslinked with CS-αβ-GP thermosensitive hydrogel exhibits anti-inflammatory properties, promotes wound healing, and enhances the transformation of M1 macrophages into M2 macrophages, with stronger effects compared to ASCs-Exos alone. This provides a new administration method for the clinical application of MSCs-Exos.
Xu et al. (Wed,) studied this question.