The Potential Role of Mesenchymal Stem Cells Derived Exosomes on the Healing of Grade II Experimentally Induced Skeletal Muscle Injury in Adult Male Albino Rats. Histological Study

Abstract

Abstract Background Musculoskeletal injuries are the most common cause of severe longterm pain and physical disability. However, there is still no efficient treatment that leads to prevention of muscle fibrosis. Cell-Free therapy using mesenchymal stem cells (MSCs) derived exosomes could provide a new promising therapy. Aim To study the potential role of MSCs-derived exosomes on the healing of experimentally induced grade II skeletal muscle injury in adult male albino rats. Materials and Methods Forty male albino Wister rats were used in this study. Five out of them were used for isolation of exosomes. The rest were randomly divided into three groups. Group I (Sham group), Group II (muscle injury group left for spontaneous healing), Group III (muscle injury treated with exosomes). Rats from each group were subdivided into two subgroups; subgroup “a and b” in which rats were sacrificed after ten days and twenty days, respectively. Muscle specimens were collected and prepared for proper histological techniques. Immuno-histochemical staining for detection of collagen type I and developmental myosin (MHCd) were also done. Morphometric study and statistical analysis were also performed. Results Granulation tissue and inflammatory cellular infiltration with significant increase in the mean area percentage of collagen fibers were noticed in subgroups of untreated muscle injury compared to the corresponding exosomes treated subgroups. This was confirmed by collagen type I immune histochemical reaction. Group III (treated with exosomes) showed better muscle regeneration and significant decrease in muscle fibrosis. Significant increase in immunohistochemical reaction of developmental myosin was noticed in exosomes treated subgroups compared to corresponding untreated muscle injury subgroups. Conclusions Exosomes enhance muscle regeneration after induced muscle injury. Exosomes also decreased muscle fibrosis and improve muscle healing.