Changes in length of sarcomeres following tenotomy of the rat soleus muscle

Abstract

Tenotomy of the proximal and distal tendons of the soleus muscle of female Wistar rats was performed and sarcomeric length and muscle fascicle length measured. On the first postoperative day muscle bellies were found shortened and their sarcomeric length considerably reduced. Four weeks following tenotomy, although the muscle bellies remained shortened, sarcomeric length was comparable with that of control muscles. Measurement of muscle fascicle lengths at this time showed that those of experimental muscles were nearly 50% less than those of control muscles. It was concluded from these experiments that a reduction of the number of sarcomeres in series had occurred, thus compensating for the reduced length of the muscle belly.

Muscle Force and Power Following Tendon Repair at Altered Tendon Length

“…As a result, the adjacent muscles may have "splinted" the EDL at or near its optimum resting length. Prior study shows that, at 1 day post tenotomy, the EDL sarcomere length is only slightly shorter than control muscle, while both the soleus and gastrocnemius sarcomere lengths are significantly decreased following tenotomy [8,46]. Additionally, simply acutely dissecting extra-muscular connective tissue results in reduced muscle force output [47].…”

Differential expression of neural cell adhesion molecule (NCAM) after tenotomy in rabbit skeletal muscle

“…Tenotomy results in numerous muscular changes that have been reported both at the gross anatomical and molecular levels. Such changes include muscle fiber atrophy [4,10,16], increased perimysial and endomysial connective tissue [ 151, decreased serial sarcomere number [2,3], decreased force-generating capacity [5, lo], increased contractile velocity [ 5 ] , and altered expression of myosin heavy chain (MHC) [13] isoforms. We previously reported that a differential functional muscle response was observed when the tenotomy was imposed upon an activated muscle ("active tenotomy", AT) compared to a passive muscle ("passive *Corresponding author.…”

Adipogenic and myogenic gene expression in rotator cuff muscle of the sheep after tendon tear

“…1,2 Fatty infiltration, muscle atrophy, and increase of interstitial connective tissue results in impaired physiological functions of tenotomized skeletal muscles. [3][4][5][6][7] Whereas rotator cuff with muscular atrophy may partly recover, 1,8 fatty infiltration of the rotator cuff muscles appears to be irreversible in the human shoulder. 1,2 Understanding the molecular pathomechanisms of these muscular changes would greatly help, first, to understand the disease process, and second, to design new treatment strategies to prevent its initiation.…”