Synergistic effects of curcumin and gamma-oryzanol solid dispersions ameliorate muscle atrophy by upregulating Nrf2 and IGF1/Insulin-Akt-mTOR activities in middle-aged rats

Abstract

Muscle atrophy is a reduction of muscle mass and size that occurs after the age of 30. The effects of the solid dispersions of curcumin (CURSD) and gamma-oryzanol (GOSD) were investigated on skeletal muscle of middle-aged Sprague-Dawley rats (12 months old) and compared to young rats (4 months old). A mixture of CURSD and GOSD supplements (GO-CURSD) increased antioxidant enzymes through the Nrf2 pathway which caused a reduction in lipid peroxidation and pro-inflammations, resulting in less muscle damage. The GO-CURSD increased IRS1-AKT-mTOR activity and suppressed Atrogin-1 and MuRF-1 genes, resulting in increased muscle mass and cross-sectional area. In addition, the GO-CURSD increased muscular glucose uptake and glycogen via IRS1-Akt up-regulated GLUT4 expression. These results suggest that the synergistic effect of CURSD and GOSD against age-related muscle atrophy regulated by increasing the antioxidant and anti-inflammatory activities, as well as improving muscle energy storage via the Nrf2 and IGF1/Insulin-Akt-mTOR signaling pathway.

Keywords

• Muscle atrophy
• Middle-aged rats
• Curcumin solid dispersion
• Gamma-oryzanol solid dispersion
• Nrf2 pathway
• IGF1/insulin-Akt-mTOR signaling pathway