Ameliorative effects ofα-lipoic acid on high-fat diet-induced oxidative stress and glucose uptake impairment of T cells

The incidence of obesity and metabolic disease continues to rise, mainly associated with consumption of a high-fat diet (HFD). Previous studies have indicated that HFD could disturb the immune system, leading to immunodeficiency and inflammation. Several mechanisms have been postulated to account for immunodeficiency associated with HFD, one being oxidative stress. To further investigate the effects of HFD on glucose metabolism and proliferative capability of T cells and the protective effects of α-lipoic acid (LA), male C57BL/6J mice were fed a normal chow (10% fat), an HFD (60% fat), an LA supplement (HFD +0.1%LA), and a N-acetyl-L-cysteine supplement (HFD +0.1% NAC) for 10 weeks. Results showed that 10-week HFD increased intracellular reactive oxygen species (ROS) production, induced oxidative stress state formation, inhibited glucose uptake, decreased ATP concentration, reduced proliferative rate, and dampened IL-2 production of T cells of mice. Administration of LA significantly alleviated these changes induced by HFD. These findings reveal that oxidative stress of T cells caused by HFD may be a key factor leading to glucose metabolism reduction and proliferative capability and function impairment of T cells. LA, as a potent agonist, could promote Nrf2 nuclear translocation and up-regulate expression of Nrf2 target genes (Ho-1 and Prdx1), which can eliminate excess ROS and restore redox balance of cells.