Ultrastructure of the optic nerve in magnesium-deficient rats.
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.
Gong
Huaqing
H
Department of Ophthalmology and Visual Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
Takami
Yumiko
Y
Amemiya
Tsugio
T
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