RESUMO
This study described the ultrastructure of healing Achilles tendon in tenotomized rat soleus muscle with particular emphasis on correlation between changes in the muscle and tendon. The right hind limbs of adult male Wister rat were tenotomized for periods of 1, 2, 3 weeks and samples were processed for electron microscopy. Following tenotomy, all animals showed good recovery indicating their tolerance for surgery. One week after tenotomy, the new tendon was characterized by numerous active fibroblasts with no restoration of tensile force. Two weeks after tenotomy, membrane bound intracytoplasmic equivalent of fibrils were more frequently seen in the tendon. They were always oriented in the same direction as material fibrils. Three weeks following tenotomy, the picture was more or less similar to that seen after two weeks. During this period, there was a partial restoration of tension which represented beginning of recovery of muscle from central core lesion
Conclusion: The changes which occurred in muscle either in the mid-portion and close to the fibre ends were concomitant with similar changes of tendon with loss of tension at the beginning and partial restoration of tension two weeks later and gradually full restoration of tension occurred