Immunocytochemical Localization of Desmin Filaments in Skeletal Muscle of Neonatal Swine

The distribution of desmin filaments in neonatal swine muscle was identified by immunoelectron microscopy. As piglets grow from 0 hr to 10 days after birth, the diameter of myofibril gradually increases and the intermyofibril space becomes narrower. The quantitative analysis suggested that the largest number of desmin filaments was identified in 0 hr after birth. Desmin filaments were identified around the immature myofibrils and also distributed in the wide intermyofibril space. These desmin filaments might be involved in the growth and myofibrillogenesis in developing myocytes. Desmin filaments formed an internal framework to connect the myofibrils and cell organelles. The entire array of myofibrils was then anchored to the sarcolemma. Desmin filaments in neonatal skeletal muscle might play a role as like as connective tissue filaments between parenchymal cells. By the quantitative analysis from fetus, neonate to adult, desmin filaments appeared to relocate from the intermyofibril spaces to the Z-lines. As myocytes mature, desmin filaments gradually acted as the integrators between the adjacent myofibrils.