Reactive oxygen species play a role in muscle wasting during thyrotoxicosis.
The role of reactive oxygen species (ROS) in muscle protein hydrolysis and protein oxidation in thyrotoxicosis has not been explored. This study indicates that ROS play a role in skeletal muscle wasting pathways in thyrotoxicosis. Two experimental groups (rats) were treated for 5 days with either 3,3',5-triiodothyronine (HT) or HT with α-tocopherol (HT + αT). Two controls were used, vehicle (Control) and control treated with αT (Control + αT). Serum T3, peritoneal fat, serum glycerol, muscle and body weight, temperature, mitochondrial metabolism (cytochrome c oxidase activity), oxidative stress parameters and proteolytic activities were examined. High body temperature induced by HT returned to normal when animals were treated with αT, although total body and muscle weight did not. An increase in lipolysis was observed in the HT + αT group, as peritoneal fat decreased significantly together with an increase in serum glycerol. GSH, GSSG and total radical-trapping antioxidant parameter (TRAP) decreased and catalase activity increased in the HT group. The glutathione redox ratio was higher in HT + αT than in both HT and Control + αT groups. Carbonyl proteins, AOPP, mitochondrial and chymotrypsin-like proteolytic activities were higher in the HT group than in the Control. HT treatment with αT restored mitochondrial metabolism, TRAP, carbonyl protein, chymotrypsin-like activity and AOPP to the level as that of the Control + αT. Calpain activity was lower in the HT + αT group than in HT and Control + αT and superoxide dismutase (SOD) activity was higher in the HT + αT group than in the Control + αT. Although αT did not reverse muscle loss, ROS was involved in proteolysis to some degree.
Laboratory of Molecular Pathology, Department of General Pathology, Universidade Estadual de Londrina, Londrina, Paraná State, Brazil.
Sara Santos
SS
Bernardes
Flávia Alessandra
FA
Guarnier
Poliana Camila
PC
Marinello
André
A
Armani
Andréa Name Colado
AN
Simão
Rubens
R
Cecchini
Alessandra Lourenço
AL
Cecchini
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects; D002154:Calpain / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D009132:Muscles / Q000187:drug effects / Q000473:pathology*; D009929:Organ Size / Q000187:drug effects; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013971:Thyrotoxicosis / Q000150:complications / Q000473:pathology*; D014284:Triiodothyronine / Q000097:blood / Q000494:pharmacology; D019282:Wasting Syndrome / Q000150:complications / Q000473:pathology*; D024502:alpha-Tocopherol / Q000494:pharmacology
D000975:Antioxidants; D017382:Reactive Oxygen Species; D014284:Triiodothyronine; D008315:Malondialdehyde; D045304:Cytochromes c; D002154:Calpain; D024502:alpha-Tocopherol