Effect of immobilization on solubility of soleus and gastrocnemius muscle collagen: -biochemical studies on collagen from soleus and gastrocnemius muscles of rat.

We have been studying mainly the changes in collagen fiber solubility with respect to its influence on immobilization of the soleus muscle and Achilles tendon of rats. We decided to investigate also the change of the collagen fiber solubility in the gastrocnemius muscle which, like the soleus muscle, is assumed to influence the range of motion of the ankle joints. The purpose of this study, therefore, was to investigate the effects of a 7-week immobilization on the solubility of the gastrocnemius muscle and soleus muscle collagen fiber of rats. The results were that in a 7-week immobilization period, hydroxyproline concentration in tissue was increased and salt and pepsin soluble collagen was decreased in both the soleus and the gastrocnemius muscles. The results suggest an increase in the collagen concentration in tissue and an increase in the intermolecular cross-link with a stronger molecular structure. As far as the amount of collagen and solubility were concerned, the immobilization had a similar influence on the collagen fiber in both muscles.