RESUMO
Unloading stress enhances oxidative stress, which in turn induces disuse muscle atrophy. This study evaluated the suppressive effect of lemon peel extract containing eriocitrin on muscle atrophy. Both lemon peel extract and eriocitrin suppressed weight loss in the gastrocnemius muscle under denervation in C57BL/6 mice. The mRNA level of ubiquitin ligases and their transcription factor were downregulated by eriocitrin. Eriocitrin inhibited the increase in lipid peroxidation and the ratio of glutathione disulfide/glutathione. These data suggest that eriocitrin ameliorated disuse muscle atrophy by suppressing the expression of ubiquitin ligase genes by its antioxidative effect.
Assuntos
Citrus/química , Flavanonas/farmacologia , Proteínas Musculares/metabolismo , Atrofia Muscular/tratamento farmacológico , Proteínas Ligases SKP Culina F-Box/metabolismo , Animais , Frutas/química , Peroxidação de Lipídeos , Masculino , Camundongos Endogâmicos C57BL , Estrutura Molecular , Denervação Muscular , Músculo Esquelético/efeitos dos fármacos , Estresse Oxidativo , Extratos Vegetais/químicaRESUMO
Acetaldehyde is the major toxic metabolite of alcohol (ethanol) and enhances fibrosis of the liver through hepatic stellate cells. Additionally, alcohol administration causes the accumulation of reactive oxygen species (ROS), which induce hepatocyte injury-mediated lipid peroxidation. Iso-α-acids, called isohumulones, are bitter acids in beer. The purpose of this study was to investigate the protective effects of iso-α-acids against alcoholic liver injury in hepatocytes in mice. C57BL/6N mice were fed diets containing isomerized hop extract, which mainly consists of iso-α-acids. After 7 days of feeding, acetaldehyde was administered by a single intraperitoneal injection. The acetaldehyde-induced increases in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were suppressed by iso-α-acids intake. Hepatic gene expression analyses showed the upregulation of detoxifying enzyme genes, glutathione-S-transferase (GST) and aldehyde dehydrogenase (ALDH). In vitro, iso-α-acids upregulated the enzymatic activities of GST and ALDH and induced the nuclear translocation of nuclear factor-erythroid-2-related factor 2 (Nfe2l2; Nrf2), a master regulator of antioxidant and detoxifying systems. These results suggest that iso-α-acid intake prevents acetaldehyde-induced liver injury by reducing oxidative stress via Nrf2-mediated gene expression.
