title: Time course of skeletal muscle loss and oxidative stress in rats with Walker 256 solid tumor.
abstract: Reactive oxygen species oxidize proteins and modulate the proteasomal system in muscle-wasting cancer cachexia. On day 5 (D5), day 10 (D10), and day 14 (D14) after tumor implantation, skeletal muscle was evaluated. Carbonylated proteins and thiobarbituric acid reactive substances were measured. Chemiluminescence was employed for lipid hydroperoxide estimation. Glutathione, superoxide dismutase, and total radical antioxidant capacity were evaluated. The proteasomal system was assessed by mRNA atrogin-1 expression. Increased muscle wasting, lipid hydroperoxide, and superoxide dismutase, and decreased glutathione levels and total radical antioxidant capacity, were found on D5 in accordance with increased mRNA atrogin-1 expression. All parameters were significantly modified in animals treated with α-tocopherol. The elevation in aldehylde levels and carbonylated proteins observed on D10 were reversed by α-tocopherol treatment. Oxidative stress may trigger signal transduction of the proteasomal system and cause protein oxidation. These pathways may be associated with the mechanism of muscle wasting that occurs in cancer cachexia.
authors.affiliation: Pathophysiology Laboratory of Free Radicals, Department of Pathological Sciences, Universidade Estadual de Londrina, 86051-990 Londrina, Brazil, Brazil.
authors.forename: Flávia A
authors.initials: FA
authors.lastname: Guarnier
authors.forename: Alessandra L
authors.initials: AL
authors.lastname: Cecchini
authors.forename: Andréia A
authors.initials: AA
authors.lastname: Suzukawa
authors.forename: Ana Leticia G C
authors.initials: AL
authors.lastname: Maragno
authors.forename: Andréa N C
authors.initials: AN
authors.lastname: Simão
authors.forename: Marcelo D
authors.initials: MD
authors.lastname: Gomes
authors.forename: Rubens
authors.initials: R
authors.lastname: Cecchini
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002279:Carcinoma 256, Walker / Q000378:metabolism / Q000473:pathology*; D005978:Glutathione / Q000378:metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology*; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D013482:Superoxide Dismutase; D005978:Glutathione