HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Morphological adaptation and protein modulation of myotendinous junction following moderate aerobic training

Davide Curzi1, Valentina Baldassarri1, Rita De Matteis2, Francesca Salamanna3, Alessandra Bolotta4, Antonio Frizziero5, Milena Fini3, Marina Marini4,6 and Elisabetta Falcieri1,7

1University of Urbino, Department of Earth, Life and Environmental Sciences, Urbino, 2University of Urbino, Department of Biomolecular Sciences, Urbino, 3Laboratory of Pre-clinic and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, 4University of Bologna, Department of Experimental, Diagnostic, and Specialty Medicine, Bologna, 5University of Padova, Department of Rehabilitation Medicine, Padova, 6Center of Sports Medicine, Don Gnocchi Foundation, IRCCS, Milano and 7CNR, Molecular Genetics Institute and Rizzoli Orthopaedic Institute, Bologna, Italy

Offprint requests to: Dr. Davide Curzi, Department of Earth, Life and Environmental Sciences, University of Urbino, 61209 Urbino, Italy. e-mail: davide.curzi@uniurb.it


Summary. Myotendinous junction is the muscle-tendon interfacethrough which the contractile force can be transferred from myofibrils to the tendon extracellular matrix. At the ultrastructural level, aerobic training can modify the distal myotendinous junction of rat gastrocnemius, increasing the contact area between tissues. The aim of this work is to investigate the correlation between morphological changes and protein modulation of the myotendinous junction following moderate training. For this reason, talin, vinculin and type IV collagen amount and spatial distribution were investigated by immunohistochemistry and confocal microscopy. The images were then digitally analyzed by evaluating fluorescence intensity. Morphometric analysis revealed a significant increased thickening of muscle basal lamina in the trained group (53.1±0.4 nm) with respect to the control group (43.9±0.3 nm), and morphological observation showed the presence of an electron-dense area in the exercised muscles, close to the myotendinous junction. Protein concentrations appeared significantly increased in the trained group (talin +22.2%; vinculin +22.8% and type IV collagen +11.8%) with respect to the control group. Therefore, our findings suggest that moderate aerobic training induces/causes morphological changes at the myotendinous junction, correlated to the synthesis of structural proteins of the muscular basal lamina and of the cytoskeleton. Histol Histopathol 30, 465-472 (2015)

Key words: Myotendinous junction, Exercise, Talin, Vinculin, Type IV collagen

DOI: 10.14670/HH-30.465