title: Ultrastructure of the optic nerve in magnesium-deficient rats.
abstract: OBJECTIVE
  The ultrastructure of the optic nerves in magnesium (Mg)-deficient rats was studied to elucidate the function of Mg.
  
  
  METHODS
  After delivery, mother Wistar Kyoto rats were fed a low-Mg diet containing 0.1 mg Mg/100 g diet with all other nutrients and distilled and deionized water. Infant rats were suckled by their mothers for 21 days and then fed the same Mg-deficient diet. Control mother rats were fed commercial rat pellets containing 24 mg Mg/100 g diet and all other nutrients. The optic nerves were examined by electron microscopy at 6 weeks of age.
  
  
  RESULTS
  In the Mg-deficient rats, serum Mg levels were significantly lower and calcium levels higher than in the control rats. Ultrastructural findings were: significantly fewer myelinated axons and significantly thinner myelin sheaths in the Mg-deficient rats than in the control and pair-fed controls, and more numerous unmyelinated axons. There were multifocal areas of destruction and necrosis in the optic nerve of Mg-deficient rats.
  
  
  CONCLUSIONS
  This study suggests that the optic nerve needs Mg for the development and maintenance of its cell structure.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
authors.forename: Huaqing
authors.initials: H
authors.lastname: Gong
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Takami
authors.forename: Tsugio
authors.initials: T
authors.lastname: Amemiya
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D016022:Case-Control Studies; D005260:Female; D008275:Magnesium Deficiency / Q000097:blood / Q000473:pathology*; D008297:Male; D017348:Microscopy, Electron, Scanning Transmission / Q000295:instrumentation; D009186:Myelin Sheath / Q000473:pathology / Q000648:ultrastructure; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000648:ultrastructure; D009900:Optic Nerve / Q000473:pathology / Q000648:ultrastructure*; D051381:Rats; D011921:Rats, Inbred WKY