Loss and renewal of thick myofilaments in glucocorticoid-treated rat soleus after denervation and reinnervation

Muscle Nerve. 1992 Nov;15(11):1290-8. doi: 10.1002/mus.880151112.


Denervation of rat soleus muscle and simultaneous administration of high doses of corticosteroids for 7 days caused marked muscle fiber atrophy and selective loss of thick myofilaments from many muscle fibers by light and electron microscopy. Myosin heavy chain/actin ratios were greatly reduced on polyacrylamide gel electrophoresis. Nerve crush instead of cut permitted reinnervation after 2 weeks and demonstrated the reversibility of the muscle changes within a week after reinnervation. There was formation of new thick filaments and their reintegration into myofibrils without further breakdown, although large areas of Z-disc streaming appeared. The mechanism of A-band breakdown remains obscure, but it presumably starts with limited proteolysis and continues with disaggregation of myosin molecules. This is consistent with our observation that the muscle fibers retain a relatively good reactivity to antibodies against myosin heavy chain 1 week after denervation and corticosteroid administration. A syndrome recalling these experiments is seen in severely asthmatic patients receiving corticosteroids and pharmacologically paralyzed for mechanical respiration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / drug effects*
  • Actin Cytoskeleton / pathology
  • Animals
  • Dexamethasone / pharmacology*
  • Electrophoresis, Polyacrylamide Gel
  • Male
  • Microscopy, Electron
  • Muscle Denervation*
  • Muscles / drug effects*
  • Muscles / metabolism
  • Muscles / pathology
  • Nerve Regeneration*
  • Organ Size / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Tarsus, Animal


  • Dexamethasone