Oxidative stress in the latissimus dorsi muscle of diabetic rats

The purpose of the present study was to investigate the effects of experime ntal diabetes on the oxidant and antioxidant status of latissimus dorsi (LD ) muscles of male Wistar rats (220 +/- 5 g, N = 11). Shortterm (5 days) dia betes was induced by a single injection of streptozotocin (STZ, 50 mg/kg, i v; glycemia >300 mg/dl). LD muscle of STZ-diabetic rats presented higher le vels of thiobarbituric acid reactive substances (TEARS) and chemiluminescen ce (0.36 +/- 0.02 nmol/mg protein and 14706 +/- 1581 cps/mg protein) than L D muscle of normal rats (0.23 +/- 0.04 nmol/mg protein and 7389 +/- 1355 cp s/mg protein). Diabetes induced a 92% increase in catalase and a 27% increa se in glutathione S-transferase activities in LD muscle. Glutathione peroxi dase activity was reduced (58%) in STZ-diabetic rats and superoxide dismuta se activity was similar in LD muscle of both groups. A positive correlation was obtained between catalase activity and the oxidative stress of LD, as evaluated in terms of TEARS (r = 0.78) and by chemiluminescence (r = 0.89). Catalase activity also correlated inversely with glutathione peroxidase ac tivity (r = 0.79). These data suggest that an increased oxidative stress in LD muscle of diabetic rats may be related to skeletal muscle myopathy.