Morphological Evidence of Telocytes in Skeletal Muscle Interstitium of Exercised and Sedentary Rodents.

Silvia Ravalli,Grazia Maugeri,Concetta Federico,Elisabetta Pricoco,Giuseppe Musumeci,Federico Roggio,Salvatore Saccone,Michelino Di Rosa,Giovanni Lauretta

doi:10.3390/biomedicines9070807

Silvia Ravalli, Grazia Maugeri + Show 7 more

Open Access

https://doi.org/10.3390/biomedicines9070807

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Abstract

Skeletal muscle atrophy, resulting from states of hypokinesis or immobilization, leads to morphological, metabolic, and functional changes within the muscle tissue, a large variety of which are supported by the stromal cells populating the interstitium. Telocytes represent a recently discovered population of stromal cells, which has been increasingly identified in several human organs and appears to participate in sustaining cross-talk, promoting regenerative mechanisms and supporting differentiation of local stem cell niche. The aim of this morphologic study was to investigate the presence of Telocytes in the tibialis anterior muscle of healthy rats undergoing an endurance training protocol for either 4 weeks or 16 weeks compared to sedentary rats. Histomorphometric analysis of muscle fibers diameter revealed muscle atrophy in sedentary rats. Telocytes were identified by double-positive immunofluorescence staining for CD34/CD117 and CD34/vimentin. The results showed that Telocytes were significantly reduced in sedentary rats at 16 weeks, while rats subjected to regular exercise maintained a stable Telocytes population after 16 weeks. Understanding of the relationship between Telocytes and exercise offers new chances in the field of regenerative medicine, suggesting possible triggers for Telocytes in sarcopenia and other musculoskeletal disorders, promoting adapted physical activity and rehabilitation programmes in clinical practice.

Highlights

The skeletal muscle is a highly dynamic and plastic tissue that promptly responds to physical activity and sedentary behavior [1]
Alexander Mauro described, for the first time, in 1961, a population of mononucleated cells which had been called “satellite cells” (SCs) by virtue of their localization: underneath the surrounding basal lamina and outside the plasma membrane of the muscle fiber they are associated with [14]. These cells have been immunophenotypically identified by Pax7 [15], M-cadherin [16], CD34 [17], and α7-integrin [18] and originate from Pax3+ progenitors in the somites of the embryo that migrate to the limb bud [19,20,21]
CTRL4W, control sedentary rats sacrificed at comparison hoc test, physical are notexercise significant, as at expected (p > 0.05)

Summary

Introduction

The skeletal muscle is a highly dynamic and plastic tissue that promptly responds to physical activity and sedentary behavior [1]. Alexander Mauro described, for the first time, in 1961, a population of mononucleated cells which had been called “satellite cells” (SCs) by virtue of their localization: underneath the surrounding basal lamina and outside the plasma membrane of the muscle fiber they are associated with [14]. These cells have been immunophenotypically identified by Pax7 [15], M-cadherin [16], CD34 [17], and α7-integrin [18] and originate from Pax3+ progenitors in the somites of the embryo that migrate to the limb bud [19,20,21]. FAPs are mesenchymal resident cells able to sustain SCs differentiation during tissue regeneration [29,30,31]

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