title: Extraocular muscle characteristics related to myasthenia gravis susceptibility.
abstract: BACKGROUND
  The pathogenesis of extraocular muscle (EOM) weakness in myasthenia gravis might involve a mechanism specific to the EOM. The aim of this study was to investigate characteristics of the EOM related to its susceptibility to myasthenia gravis.
  
  
  METHODS
  Female F344 rats and female Sprague-Dawley rats were assigned to experimental and control groups. The experimental group received injection with Ringer solution containing monoclonal antibody against the acetylcholine receptor (AChR), mAb35 (0.25 mg/kg), to induce experimental autoimmune myasthenia gravis, and the control group received injection with Ringer solution alone. Three muscles were analyzed: EOM, diaphragm, and tibialis anterior. Tissues were examined by light microscopy, fluorescence histochemistry, and transmission electron microscopy. Western blot analysis was used to assess marker expression and ELISA analysis was used to quantify creatine kinase levels. Microarray assay was conducted to detect differentially expressed genes.
  
  
  RESULTS
  In the experimental group, the EOM showed a simpler neuromuscular junction (NMJ) structure compared to the other muscles; the NMJ had fewer synaptic folds, showed a lesser amount of AChR, and the endplate was wider compared to the other muscles. Results of microarray assay showed differential expression of 54 genes in the EOM between the experimental and control groups.
  
  
  CONCLUSIONS
  Various EOM characteristics appear to be related to the increased susceptibility of the EOM and the mechanism of EOM weakness in myasthenia gravis.
authors: Department of Geratology, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, PR China.
authors: Rui
authors: R
authors: Liu
authors: Hanpeng
authors: H
authors: Xu
authors: Guiping
authors: G
authors: Wang
authors: Jie
authors: J
authors: Li
authors: Lin
authors: L
authors: Gou
authors: Lihua
authors: L
authors: Zhang
authors: Jianting
authors: J
authors: Miao
authors: Zhuyi
authors: Z
authors: Li
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004198:Disease Susceptibility; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005453:Fluorescence; D007150:Immunohistochemistry; D046529:Microscopy, Electron, Transmission; D009157:Myasthenia Gravis / Q000503:physiopathology*; D009469:Neuromuscular Junction / Q000503:physiopathology; D009801:Oculomotor Muscles / Q000503:physiopathology*; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley