Effect of Bangle (Zingiber purpureum) extract and low-intensity exercise on mTOR phosphorylation and autophagy flux in skeletal muscles of rats on a high-fat diet

Abstract

High-fat diet (HFD) is associated with impairment of insulin sensitivity. We investigated the effects of Bangle (Zingiber purpureum) extract (Ba) with exercise training (Ex) on phosphorylation of Akt and mammalian target of rapamycin (mTOR), and autophagy flux in the gastrocnemius (GM) of HFD-fed rats. The rats, on a diet providing 45% of energy from fat, were divided into four groups: untreated (HFD), 1.5% Ba-treated (HFD + Ba), 1.5% Ba with Ex-treated (HFD + Ba + Ex), and Ex-treated (HFD + Ex) groups. The controls were fed a normal diet. The homeostatic model assessment of insulin resistance index and non-esterified fatty acid levels were decreased in the HFD + Ba + Ex. The HFD + Ba + Ex showed decreased phosphorylated Akt and mTOR levels, and increased levels of autophagy flux markers, LC3B-II and Beclin 1, compared to the HFD. In conclusion, the combination of Ba and Ex modulates Akt/mTOR phosphorylation and the autophagy flux in the GM and may attenuate insulin resistance induced by a HFD.

Keywords

• Bangle
• Mammalian target of rapamycin
• Autophagy
• Skeletal muscle
• High-fat diet