Muscle aging and oxidative stress in wild-caught shrews

Abstract Red-toothed shrews (Soricidae, subfamily Soricinae) are an intriguing model system to examine the free-radical theory of aging in wild mammals, given their short ( Sorex palustris ) and sympatrically distributed short-tailed shrews ( Blarina brevicauda ) were therefore assessed for oxidative stress markers, protective antioxidant enzymes and apoptosis. Activity levels of catalase and glutathione peroxidase increased with age in both species. Similarly, Cu,Zn-superoxide dismutase isoform content was elevated significantly in older animals of both species (increases of 60% in the water shrew, 25% in the short-tailed shrew). Only one oxidative stress marker (lipid peroxidation) was age-elevated; the others were stable or declined (4-hydroxynonenal adducts and dihydroethidium oxidation). Glutathione peroxidase activity was significantly higher in the short-tailed shrew, while catalase activity was 2× higher in water shrews. Oxidative stress indicators were on average higher in short-tailed shrews. Apoptosis occurred in