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Terminal intramuscular motor innervation and motor end-plates in thyrotoxic myopathy

V M Kazakov1

  • 1I.P. Pavlov Medical Institute, St. Petersburg, Russia.

Neuromuscular Disorders : NMD
|January 1, 1992
PubMed

Insights

Thyrotoxic myopathy in mice and humans shows excessive axonal branching and nerve terminal damage. These findings suggest thyroid hormones may disrupt nerve function and neuromuscular interactions.

Area of Science:

  • Neurology
  • Endocrinology
  • Muscle physiology

Background:

  • Thyrotoxic myopathy is a neuromuscular complication of hyperthyroidism.
  • The precise pathological mechanisms underlying thyrotoxic myopathy are not fully understood.
  • Previous research suggests alterations at the neuromuscular junction.

Purpose of the Study:

  • To investigate the structural changes in peripheral nerves and neuromuscular junctions in experimental and human thyrotoxic myopathy.
  • To explore the potential role of thyroid hormone excess in axonal and neuromuscular pathologies.

Main Methods:

  • Induction of thyrotoxic myopathy in 64 mice.
  • Histopathological examination of muscle and nerve tissues from mice.
  • Analysis of end-plate morphology and cholinesterase levels in mice.
  • Clinical and pathological assessment of muscle and nerve tissues from 43 patients with thyrotoxic myopathy.

Main Results:

  • Experimental mice exhibited excessive axonal branching and degenerative changes in preterminal axons.
  • Reduced mean end-plate diameter and apparent decreased end-plate cholinesterase levels were observed in mice.
  • Similar axonal branching and degenerative changes were identified in patients with thyrotoxic myopathy.
  • The pathological findings in mice mirrored those observed in human patients.

Conclusions:

  • Excess thyroid hormone is associated with significant axonal and neuromuscular junction abnormalities.
  • Thyroid hormone excess may interfere with axonal transport mechanisms.
  • These findings highlight potential disruptions in neuromuscular interactions due to hyperthyroidism.

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