BACKGROUND: Wound healing is a complicated biological process that leads to the regeneration of damaged skin tissue. Determining the methods to promote wound healing has become a hot topic in medical cosmetology and tissue repair research. Mesenchymal stem cells (MSCs) are a group of stem cells with the potential of self-renewal and multidifferentiation. MSCs transplantation has a broad application prospect in wound healing therapy. Many studies have demonstrated that the therapeutic capacity of MSCs is mainly mediated by paracrine actions. Exosomes (EXOs), which are nanosized vesicles carrying a variety of nucleic acids, proteins and lipids, are an important component of paracrine secretion. It has been demonstrated that exosomal microRNAs (EXO-miRNAs) play a key role in the function of exosomes. METHODS: In this review, we focus on current research on miRNAs from MSC-derived exosomes (MSC-EXO miRNAs) in terms of sorting, releasing and function and their effects on inflammation regulation, epidermal cell function, fibroblast function, and extracellular matrix formation. At last, we discuss the current attempts to improve the treatment of MSC-EXO-miRNAs. RESULTS: Many studies have demonstrated that MSC-EXO miRNAs play a key role in promoting wound healing. They have been shown to regulate inflammation response, enhance epidermal cell proliferation and migration, stimulate fibroblast proliferation and collagen synthesis, and regulate extracellular matrix formation. Besides, there have been a number of strategies developed to promote MSC-EXO and MSC-EXO miRNAs for wound healing treatment. CONCLUSION Utilizing the association of exosomes from MSCs with miRNAs may be a promising strategy to promote trauma healing. MSC-EXO miRNAs may provide a new approach to promote wound healing and improve the quality of life for patients with skin injuries.

Objective To discuss the effect of H2 on osteoclast differentiation of RAW264.7 cells induced by RANKL and RANKL/TNF-α.MethodsRAW264.7 cells were treated with H2 in the presence of RANKL and RANKL/TNF-α.RAW264.7 cells viability was assessed by CCK-8.Test the Oxidative Stress of the induced RAW264.7.The number of TRAP-positive cells were counted under light microscopy.The levels of cathepsin K (CTK) and matrix metalloprotein-9(MMP-9) mRNA were analyzed by real-time PCR.ResultsH2 can not influence the RAW264.7 cell viability but can lower oxidative stress.The significant difference(P<0.05) indicated that H2 could significantly decrease the number of TRAP-positive MNCs.The significant difference among the 4 groups in CTK and MMP-9 genes (P<0.05) indicated that H2 could down-regulate their mRNA expression.ConclusionH2 can reduce the oxidative stress and inhibit differentiation of RAW264.7 cells into osteoclasts.