Mesenchymal stem cells derived‐exosomes as a new therapeutic strategy for acute soft tissue injury

Abstract The study aimed to investigate the role of exosomes derived from rat bone marrow mesenchymal stem cells (rBMSCs) in acute soft tissue injury and its related mechanisms. Exosomes were isolated from rBMSCs and characterized by Nanosight NS300 particle size analyser (NTA), transmission electron microscopy (TEM), and western blot. Twenty four rats were randomly divided into four groups (n = 6): control group, strike group, rBMSCs group, and rBMSCs‐exo group. Haematoxylin‐eosin (HE) staining was used to observe the morphology. Real‐time quantification PCR (RT‐qPCR) and western blot were used to analyse the expression of IL‐1A , IL‐12A , COL11A1 , COL4A4 , and Wnt4 . NTA, TEM and western blot results showed that exosomes isolated from rBMSCs were cup‐shaped morphology with a size of about 100 nm. HE staining showed that there was severe soft tissue inflammation in strike group, and the symptoms were alleviated after rBMSCs and rBMSCs‐exo treatment. RT‐qPCR and western blot indicated that in the strike group, the expression levels of IL‐1A and IL‐12A were significantly increased, and their expressions were decreased markedly by exosomes treatment. In addition, after treatment, the expression levels of COL11A1 and Wnt4 were up‐regulated, while the expression of COL4A4 was down‐regulated. Exosomes isolated from rBMSCs could improve acute soft tissue injury, and may be used as a new therapeutic strategy acute soft tissue injury. Significance of the study Acute soft tissue injury is a common clinical exercise injury, which has a significant impact on people's health and work ability. Exosomes have been attracting increasing attention as a media of cell‐to‐cell communication. This study showed that exosomes isolated from rBMSCs could improve acute soft tissue injury by inhibiting inflammatory response, regulating the levels of COL11A1 and COL4A4 , and up‐regulating the expression of Wnt4 . These will provide a new therapy strategy of acute soft tissue injury, and improve our understanding of the occurrence and development in acute soft tissue injury.