Ultrastructural and immunohistochemical characteristics of telocytes in the skin and skeletal muscle of newborn rats

•Transmission electron microscopic and immunohistochemical characteristics of telocytes.•The evidence of the presence of telocytes in young age and their ability to release vesicles.•The role of telocytes in pathologies and regenerative medicine.

Telocytes (TCs) are newly described interstitial cells that might play a role in normal and pathological conditions. The aim of this study was designed to investigate its existence in the skin and skeletal muscle of one day old newborn rats and to study their ultrastructure and immunohistochemical characteristics. Ten rats (one day old newborn) were used in this study. Dorsal skin and femoral skeletal muscle samples were obtained and examined by CD117, CD34, semi-thin and ultrathin sections examination. Semi-thin sections examination revealed multiple spindle shape cells with cytoplasmic extension in the skin and in between muscle fibers. Telocytes showed positive reaction for both CD117 and CD34 immunostains. By electron microscopy these cells were spindle shaped with small cell bodies and long processes. Telocytes showed homo-cellular junctions between two adjacent telocytes and hetero-cellular junctions between telocytes and other cellular and non-cellular structures. Multiple vesicles were seen either intra-cellular or budding from the cell membrane or detached from the telocytes leaving caveolae. It could be concluded that telocytes are present in the skin and skeletal muscle of one day old newborn rats. They might play a role in pathologies and regenerative medicine due to their ability to release vesicles.