BACKGROUND: Oxidative stress-induced reactive oxygen species are associated with the clinical manifestation of insulin resistance. Evidence suggests that antioxidant treatment may reduce this incidence. AIM OF THE STUDY: This study determined whether glucose oxidase (GO)-induced insulin resistance in cultured skeletal muscle cells could be ameliorated by pre-treatment with gamma-tocopherol (GT). METHODS: Insulin sensitivity in L6 myotubes was assessed by 2-deoxy-D: -[(3)H]-glucose uptake. The phosphorylation of distal insulin signaling proteins Akt and the Akt substrate AS160 were determined by western blot. RESULTS: One hour treatment with 100 mU/ml GO decreased insulin-stimulated glucose uptake (P < 0.001). Pre-treatment with GT either partially (100 microM) or completely (200 microM) restored insulin-stimulated glucose uptake in cells after GO-induced insulin resistance. GO-induced oxidative stress did not impair insulin stimulated phosphorylation of Akt or AS160, but 200 microM GT increased insulin-stimulated phosphorylation of these key signaling proteins (P < 0.05). CONCLUSIONS: High-dose (200 microM) GT treatment ameliorated oxidative stress-induced insulin resistance in cultured rat L6 skeletal muscle cells.
BACKGROUND: Oxidative stress-induced reactive oxygen species are associated with the clinical manifestation of insulin resistance. Evidence suggests that antioxidant treatment may reduce this incidence. AIM OF THE STUDY: This study determined whether glucose oxidase (GO)-induced insulin resistance in cultured skeletal muscle cells could be ameliorated by pre-treatment with gamma-tocopherol (GT). METHODS: Insulin sensitivity in L6 myotubes was assessed by 2-deoxy-D: -[(3)H]-glucose uptake. The phosphorylation of distal insulin signaling proteins Akt and the Akt substrate AS160 were determined by western blot. RESULTS: One hour treatment with 100 mU/ml GO decreased insulin-stimulated glucose uptake (P < 0.001). Pre-treatment with GT either partially (100 microM) or completely (200 microM) restored insulin-stimulated glucose uptake in cells after GO-induced insulin resistance. GO-induced oxidative stress did not impair insulin stimulated phosphorylation of Akt or AS160, but 200 microM GT increased insulin-stimulated phosphorylation of these key signaling proteins (P < 0.05). CONCLUSIONS: High-dose (200 microM) GT treatment ameliorated oxidative stress-induced insulin resistance in cultured rat L6 skeletal muscle cells.
Authors: Andrew L Carey; Andrew L Siebel; Medini Reddy-Luthmoodoo; Alaina K Natoli; Wilissa D'Souza; Peter J Meikle; Dmitri Sviridov; Brian G Drew; Bronwyn A Kingwell Journal: PLoS One Date: 2013-02-21 Impact factor: 3.240