Cell and molecular mechanisms of regeneration and reorganization of skeletal muscles.

The process of skeletal muscle regeneration comprises four phases: degeneration, inflammatory and immune response, regeneration and remodelling, which are regulated by a number of molecules secreted, by muscle cells and immune, epithelial, interstitial and other cells present in skeletal tissue. The molecules include cytokines, growth factors, erythropoietin, enzymes, and reactive oxygen and nitrogen species (RONS). Some of them are potent stimulators of the proliferation and growth of muscle cells while others may inhibit these processes. For several years, cytokines and growth factors have been used in regenerative medicine in the form of platelet concentrate or recombinant preparations. There have also been attempts to use muscle cells and muscle-derived stem cell (MDSC) cultures, which contain satellite glial cells, mesoanglioblasts and pericytes, as well as cultures of isolated satellite glial cells or myoblasts. The aim of the paper is to present current knowledge concerning the molecular and cellular mechanisms of regeneration and remodelling of skeletal muscles, the role of cytokines and growth factors in the proliferation of satellite glial cells and the possibilities of therapeutic use of stem cells of different origin for stimulating regeneration of damaged muscle fibres.