Expression and role of lncRNAs in the regeneration of skeletal muscle following contusion injury.

Studies performed previously have indicated that long non-coding RNAs (lncRNAs) may be involved in skeletal muscle regeneration; however, the roles of lncRNAs during the repair of skeletal muscle contusion remain unclear. The present study established a mouse skeletal muscle contusion injury model to identify the roles of lncRNAs that are specifically enriched in the skeletal muscle, namely metastasis-associated lung adenocarcinoma transcript 1 (Malat1), H19, myogenesis-associated lnc (lnc-mg), long intergenic non-protein coding RNAs (linc)-muscle differentiation 1 (linc-MD1), linc-yin yang 1 (linc-YY1) and sirtuin 1-antisense (Sirt1-AS). Morphological analyses revealed that fibrotic scars and regenerating myofibers were formed in the muscle following contusion injury. Gene expression was analyzed by reverse transcription-quantitative polymerase chain reaction. The data revealed that the expression of inflammatory cytokines, myogenic regulatory factors and angiogenic factors increased significantly following skeletal muscle contusion. Additionally, various lncRNAs, including Malat1, H19, lnc-mg, linc-MD1, linc-YY1 and Sirt1-AS were also upregulated. Correlation was also observed between lncRNAs and regulatory factors for skeletal muscle regeneration including transforming growth factor-β1, myogenic differentiation, myogenin, myogenic factor 5 (myf5), myf6, hypoxia-inducible factor-1α and angiopoietin 1. In conclusion, lncRNAs may serve important roles in the regeneration of skeletal muscle following contusion injury, which provides a promising therapy avenue for muscle injury.