Abstract
One of the main properties of skeletal muscles is elastic behaviour, which is related to the intramuscular collagen fibrillar arrangement. In general, immobilized muscle shows decreased elasticity, but it is not known how changes in elasticity affect the collagen fibrillar arrangement. We therefore examined the collagen fibrillar arrangements in the endomysium of the soleus muscles after immobilization of ankle joint of the rat. Five male wistar rats (age 18-22 weeks, weight 350-460g) were used in this study. Right ankle of the rat was immobilized in planter-flexed position using plaster cast. After four weeks, the soleus muscles were biopsied. Muscles were stretched with a 4g sinker, and fixed in 3% glutaraldehyde. According to the cell-maceration method, muscle samples were immersed in a 10% aqueous solution of sodium hydroxide, and then rinsed in distilled water at room temperature. The specimens were observed using a scanning electron microscope. Other muscle samples embedded in Epon, and blocks of muscle tissue were sectioned logitudinally. The sections were observed with a light microscope and an electron microscope. As a result ; The collagen fibrilles in the endomysium after immobilization were hypertrophic, and the transverse component of collagen fibrilles was increased. The sarcomere lengths after immobilization were decreased. We presume that hypertrophy of the collagen fibrilles after immobilization is affected by intermolecular cross-links, and that an increased transverse component of collagen fibrilles might affect the series elastic component of immobilized soleus muscle.
