The effect of methylmercury on skeletal muscle in the rat: a histopathological study.
Methylmercury (MeHg)-induced neurotoxicity includes skeletal muscle symptoms (extremity weakness and wasting, muscle cramp) in addition to ataxia and disturbances of sensory and visual function. The underlying mechanisms responsible for the skeletal muscle symptoms are still poorly understood. In this study the effects of MeHg exposure on skeletal muscle were investigated in rats receiving orally administered MeHgCl at 5 mg/kg/day for 12 days. MeHg-treated rats gradually lost body weight and showed muscle weakness and wasting. Seven days after the last MeHg dose, MeHg levels in the skeletal muscle were as high as those in liver, kidney, or cerebrum. The obvious histopathological finding in skeletal muscle was a decrease in mitochondrial enzyme activity. These changes were more prominent in mitochondria-rich soleus muscle than in extensor digitorum longus muscle. Our findings confirm that MeHg exposure disturbs mitochondrial energy metabolism in skeletal muscle.
Usuki
F
F
Department of Clinical Medicine, National Institute for Minamata Disease, Hama, Japan. usuki@infobears.or.jp
Yasutake
A
A
Matsumoto
M
M
Umehara
F
F
Higuchi
I
I
D000659:AMP Deaminase / Q000032:analysis; D000284:Administration, Oral; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002531:Cerebellum / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000032:analysis; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008767:Methylmercury Compounds / Q000008:administration & dosage / Q000633:toxicity*; D008931:Mitochondria, Muscle / Q000187:drug effects* / Q000201:enzymology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013385:Succinate Dehydrogenase / Q000032:analysis; D019282:Wasting Syndrome / Q000139:chemically induced
D008767:Methylmercury Compounds; D013385:Succinate Dehydrogenase; D003576:Electron Transport Complex IV; D000659:AMP Deaminase; C004925:methylmercuric chloride