Effect of glucose tolerance on muscle atrophy in streptozotocin‐induced diabetic rats

Abstract

Diabetic mellitus (DM) is characterized by an increased plasma glucose level, and reduced glucose uptake can activate protein degradation machinery leading to autophagy in skeletal muscle fibers. Thus, in this study we investigated the effect of glucose tolerance on numerous markers related to muscle atrophy in skeletal muscles obtained from streptozotocin‐induced diabetic rats. Male Sprague‐Dawley rats (n=8, eight‐week‐old) were divided into two experimental groups: diabetic (group‐DM, induced i.p. by streptozotocin at 60 mg/kg) and group‐C (treated with vehicle for eight weeks). The blood glucose level in the rats was determined each week using blood samples obtained by venipuncture of a tail vein. After eight weeks, the rats were sacrificed by decapitation and skeletal muscle tissue was collected for RNA isolation. The differential expression of muscle atrophy‐related genes such as MuRF1 and MAFbx was then analyzed. MuRF1 expression was significantly increased in the skeletal muscles of the diabetic rats. Our results indicate the expression of specific muscle atrophy‐related genes increased in diabetic‐induced muscle atrophy.Funding: BioGreen21 Program (Code No. 20070401‐034‐006‐009‐02‐00), Rural Development Administration, Korea